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CRISPR is a powerful tool for editing genomes, meaning it allows researchers to easily alter DNA sequences and modify gene function. It has many potential applications, including correcting genetic defects, treating and preventing the spread of diseases, and improving the growth and resilience of crops. However, despite its promise, the technology also raises ethical concerns.

In popular usage, "CRISPR" (pronounced "crisper") is shorthand for "CRISPR-Cas9." CRISPRs are specialized stretches of , and the protein Cas9 - where Cas stands for "CRISPR-associated" - is an that acts like a pair of molecular scissors, capable of cutting strands of DNA.

CRISPR technology was adapted from the natural defense mechanisms of and archaea, a domain of relatively simple single-celled microorganisms. These organisms use CRISPR-derived , a molecular cousin to DNA, and various Cas proteins to foil attacks by . To foil attacks, the organisms chop up the DNA of viruses and then stow bits of that DNA in their own genome, to be used as a weapon against the foreign invaders should those viruses attack again.

When the components of CRISPR are transferred into other, more complex, organisms, those components can then manipulate genes, a process called "gene editing." No one really knew what this process looked like until 2017, when a team of researchers led by Mikihiro Shibata of Kanazawa University in Japan and Hiroshi Nishimasu of the University of Tokyo showed, for the very first time, what it looks like when a CRISPR is in action, Live Science previously reported.

Related: Genetics by the numbers: 10 tantalizing tales

Key components of CRISPR

CRISPRs: The term "CRISPR" stands for "clusters of regularly interspaced short palindromic repeats" and describes a region of DNA made up of short, repeated sequences with so-called "spacers" sandwiched between each repeat.

When we talk about repeats in the genetic code, we're talking about the ordering of rungs within the spiral ladder of a DNA molecule. Each rung contains two chemical bases bound together: A base called adenine (A) links up to another called thymine (T), and the base guanine (G) pairs with cytosine (C).

In a CRISPR region, these bases appear in the same order several times, and in these repeated segments, they form what's known as "palindromic" sequences, according to the Max Planck Institute. A palindrome, like the word "racecar," reads the same forward as it does backward; similarly, in a palindromic sequence, bases on one side of the DNA ladder match those on the opposing side when you read them in opposite directions.

For example, a super simple palindromic sequence might look like this:

Short palindromic repeats appear throughout CRISPR regions of DNA, with each repeat bookended by "spacers." Bacteria swipe such spacers from viruses that have attacked them, meaning they incorporate a bit of viral DNA into their own genome. These spacers serve as a bank of memories, which enables the bacteria to recognize the viruses if they should ever attack again. You can also think of spacers like "Wanted" posters, providing a snapshot of the bad guys so they can be easily spotted and brought to justice.

Related: Going viral: 6 new findings about viruses

Rodolphe Barrangou and a team of researchers at Danisco, a food ingredients company, first demonstrated this process experimentally. In a 2007 paper published in the journal Science, the researchers used Streptococcus thermophilus bacteria, which are commonly found in yogurt and other dairy cultures, as their model, according to the Joint Genome Institute, part of the U.S. Department of Energy. They observed that after a viral attack, the bacteria incorporated new spacers into their CRISPR regions. Moreover, the DNA sequence of these spacers was identical to parts of the virus genome.

The team also manipulated the spacers by removing them and inserting new viral DNA sequences in their place. In this way, the researchers were able to alter the bacteria's resistance to an attack by a specific virus, confirming CRISPRs' role in regulating bacterial immunity.

CRISPR RNA (crRNA): CRISPR regions of DNA act as a kind of bank of viral memories; but for that stored information to be useful elsewhere in the cell, it must be copied, or "transcribed," into a different genetic molecule called RNA. Unlike DNA sequences, which remain lodged inside the DNA molecule, this CRISPR RNA (crRNA) can roam about the cell and team up with proteins - namely the molecular scissors that snip viruses to bits.

RNA also differs from DNA in that it's only one strand, rather than two, meaning it looks like just a half of a ladder. To build an RNA molecule, one part of the CRISPR acts as a template and proteins called polymerases swoop in to construct an RNA molecule that is "complementary" to that template, meaning the two strands' bases would fit together like puzzle pieces. For example, a G in the DNA molecule would get transcribed as a C in the RNA.

Each snippet of CRISPR RNA contains a copy of a repeat and a spacer from a CRISPR region of DNA, according to a 2014 review by Jennifer Doudna and Emmanuelle Charpentier, published in the journal Science. The crRNA interacts with the Cas9 protein and another kind of RNA, called "trans-activating crRNA" or tracrRNA, in order to help bacteria fend off viruses.

Cas9: The Cas9 protein is an enzyme that cuts foreign DNA. The protein binds to crRNA and tracrRNA, which together guide Cas9 to a target site on the virus's DNA strand where the protein will make its cut. The target DNA that the Cas9 will cut through is complementary to a 20-nucleotide stretch of the crRNA, where a "nucleotide" is a building block of DNA that contains one base.

Using two separate regions or "domains" on its structure, Cas9 cuts both strands of the DNA double helix, making what is known as a "double-stranded break," according to the 2014 Science article.

There is a built-in safety mechanism that ensures that Cas9 doesn't just cut just anywhere in a genome. Short DNA sequences known as "protospacer adjacent motifs," or PAMs, serve as tags and sit adjacent to the target DNA sequence. If the Cas9 complex doesn't see a PAM next to its target DNA sequence, it won't cut. This is one possible reason that Cas9 doesn't ever attack the CRISPR region in bacteria, according to a 2014 review published in Nature Biotechnology.

How CRISPR works as a genome-editing tool

Genomes encode a series of messages and instructions within their DNA sequences, and genome editing involves changing those sequences, thereby changing the messages they contain. This can be done by inserting a cut or break in the DNA and tricking a cell's natural DNA repair mechanisms into introducing the targeted changes. CRISPR-Cas9 provides a means to do so.

In 2012, two pivotal research papers were published in the journals Science and , describing how the bacterial CRISPR-Cas9 could be used to chop up any DNA, not just that of viruses. In this way, the natural CRISPR system could be transformed into a simple, programmable genome-editing tool.

To direct Cas9 to snip a specific region of DNA, scientists can simply change the sequence of the crRNA, which binds to a complementary sequence in the target DNA, the studies concluded.In the 2012 Science article, Martin Jinek and his colleagues further simplified the system by fusing crRNA and tracrRNA to create a single "guide RNA." Thus, genome editing requires only two components: a guide RNA and the Cas9 protein.

"Operationally, you design a stretch of 20 base pairs that match a gene that you want to edit," and from there, one can figure out what the complementary crRNA sequence would be, George Church, a professor of genetics at Harvard Medical School, told Live Science. Church emphasized the importance of making sure that the nucleotide sequence is found only in the target gene and nowhere else in the genome.

"Then the RNA plus the protein [Cas9] will cut - like a pair of scissors - the DNA at that site, and ideally nowhere else," Church explained. Once the DNA is cut, the cell's natural repair mechanisms kick in and work to piece the DNA back together, and at this point, edits can be made to the genome. There are two ways this can happen:

According to the Huntington's Outreach Project at Stanford University, one repair method involves gluing the two cuts back together. This method, known as "non-homologous end joining," tends to introduce errors where nucleotides are accidentally inserted or deleted, resulting in that could disrupt a gene.

In the second method, the break is fixed by filling in the gap with a sequence of nucleotides. In order to do so, the cell uses a short strand of DNA as a template. Scientists can supply the DNA template of their choosing, thereby writing-in any gene they want, or correcting a mutation.

Who discovered CRISPR?

Scientists originally discovered the CRISPRs in bacteria in 1987, but they didn't initially understand the biological significance of the DNA sequences, and they didn't yet call them "CRISPRs," according to Quanta Magazine. Yoshizumi Ishino and colleagues at Osaka University in Japan first found the characteristic nucleotide repeats and spacers in the gut microbe , and as the technology for genetic analysis improved in the 1990s, other researchers found CRISPRs in many other microbes.

Francisco Mojica, a scientist at the University of Alicante in Spain, was the first to describe the distinct characteristics of CRISPRs and found the sequences in 20 different microbes, according to a 2016 report in the journal Cell. At one point, he dubbed the sequences "short regularly spaced repeats" (SRSRs), but he later suggested that they be called CRISPRs instead. The term CRISPR first appeared in a 2002 report, published in the journal Molecular Microbiology and authored by Ruud Jansen of Utrecht University, with whom Mojica had been in correspondence.

In the following years, scientists also discovered Cas genes and the function of Cas enzymes, and they figured out that the spacers in CRISPRs came from invasive viruses, Quanta reported.

Among these pioneering researchers was Jennifer Doudna, a professor of biochemistry, biophysics and structural biology at the University of California, Berkeley, who went on to share the 2020 Nobel Prize in chemistry with Emmanuelle Charpentier, director of the Max Planck Unit for the Science of Pathogens. The two scientists are credited with adapting the bacterial CRISPR/Cas system into a handy gene-editing tool, Live Science previously reported.

Charpentier initially discovered tracrRNA while studying the bacteria Streptococcus pyogenes, which causes a range of diseases from tonsillitis to sepsis. Having uncovered tracrRNA as a previously unknown component of the CRISPR/Cas system, Charpentier began collaborating with Doudna to recreate that system in a test tube. In 2012, the team published their seminal work in the journal Science, announcing that they'd successfully simplified the molecular scissors into a gene-editing tool.

Some thought that biochemist Feng Zhang of the Broad Institute might also earn the Nobel for his own, separate work with the CRISPR system, Science Magazine reported. Zhang demonstrated that the CRISPR system works in mammalian cells, and based on this work, the Broad Institute earned the first patent for the use of CRISPR gene-editing technology in eukaryotes, or complex cells with nuclei to hold their DNA.

How has CRISPR been used?

(Image credit: KEITH CHAMBERS/SCIENCE PHOTO LIBRARY via Getty Images)

In 2013, researchers in the labs of Church and Zhang published the first reports describing the use of CRISPR-Cas9 to edit human cells in an experimental setting. Studies conducted in lab dish and animal models of human disease have demonstrated that the technology can effectively correct genetic defects. Examples of such diseases include cystic fibrosis, cataracts and Fanconi anemia, according to a 2016 review article published in the journal Nature Biotechnology. These studies have paved the way for therapeutic applications in humans.

In the realm of medicine, CRISPR has been tested in early-stage clinical trials as cancer therapy and as a treatment for an inherited disorder that causes blindness. It's also been investigated as a strategy for preventing the spread of Lyme disease and malaria from viral vectors to people, and it's also been studied in animal models of HIV as a way to rid infected cells of the virus, Live Science previously reported. One research team in China attempted to treat a human patient's HIV using CRISPR, and while the treatment wasn't successful in curing the infection, the gene therapy also didn't cause any harmful effects, Live Science reported.

"I think the public perception of CRISPR is very focused on the idea of using gene editing clinically to cure disease," said Neville Sanjana of the New York Genome Center and an assistant professor of biology, neuroscience and physiology at New York University. "This is no doubt an exciting possibility, but this is only one small piece."
Related: 10 amazing things scientists just did with CRISPR
CRISPR technology has also been applied in the food and agricultural industries to engineer probiotic cultures and to vaccinate industrial cultures (yogurt, for example) against viruses. It is also being used in crops to improve yield, drought tolerance and nutritional properties.

One other potential application is to create gene drives, a genetic engineering technique that increases the chances of a particular trait passing on from parent to offspring; this kind of genetic engineering derives from a natural phenomenon, where specific versions of genes are more likely to be inherited. Eventually, over the course of generations, the trait spreads through entire populations, according to the Wyss Institute. Gene drives could be used for various applications, such as eradicating invasive species or reversing pesticide and herbicide resistance in crops, according to a 2014 report published in the journal .

During the COVID-19 pandemic, the CRISPR-Cas9 system has been used to develop various diagnostic tests for the viral infection, BBC News reported.

In April 2017, a team of researchers released research in the journal Science that they had programmed a CRISPR molecule to find strains of viruses, such as Zika, in blood serum, urine and saliva.

On Aug. 2, 2017, scientists revealed in the journal Nature that they had removed a heart disease defect in an embryo successfully using CRISPR.

On Jan. 2, 2018, researchers announced that they may be able to stop fungi and other problems that threaten chocolate production using CRISPR to make the plants more resistant to disease.

On April 16, 2018, researchers upgraded CRISPR to edit thousands of genes at once, according to research published by the journal BioNews.

In addition, CRISPR has recently been used in the following ways:

However, despite its wide range of uses, the tool is not without its drawbacks.

"I think the biggest limitation of CRISPR is it is not a hundred percent efficient," Church told Live Science. That means, in a given experiment, CRISPR may successfully edit only a percentage of the targeted DNA. According to the 2014 Science article by Doudna and Charpentier, in a study conducted in rice, gene editing occurred in nearly 50% of the cells that received the Cas9-RNA complex. Meanwhile, other analyses have shown that depending on the target, editing efficiencies can reach as high as 80% or more.

The technology can also create "off-target effects" when DNA is cut at sites other than the intended target. This can lead to the introduction of unintended mutations. Furthermore, Church noted, even when the system cuts on target, there is a chance of not getting a precise edit. He called this "genome vandalism."

Potential risks and ethical concerns of using CRISPR

The many potential applications of CRISPR technology raise questions about the ethical merits and consequences of tampering with genomes. And in particular, a slew of ethical debates flared up in 2018 when He Jiankui, formerly a biophysicist at the Southern University of Science and Technology in Shenzhen, announced that his team had edited DNA in human embryos and thus created the world's first gene-edited babies.

He was subsequently sentenced to three years in prison and fined 3 million yuan ($560,000) for practicing medicine without a license, violating Chinese regulations on human-assisted reproductive technology and fabricating ethical review documents, Live Science previously reported. But even after his sentencing, He's experiments raised questions about how the use of CRISPR should be regulated going forward, especially given that the technology is still fairly new.

Illegal experimentation in human embryos represents an extreme misuse of CRISPR, of course, but even seemingly ethical uses of the technology could carry risks, scientists say.

In general, making genetic modifications to human embryos and reproductive cells such as sperm and eggs is known as germline editing. Since changes to these cells can be passed on to subsequent generations, using CRISPR technology to make germline edits has raised a number of ethical concerns.

Variable efficacy, off-target effects and imprecise edits all pose safety risks. In addition, there is much that is still unknown to the scientific community. In a 2015 article published in Science, David Baltimore and a group of scientists, ethicists and legal experts note that germline editing raises the possibility of unintended consequences for future generations "because there are limits to our knowledge of human genetics, gene-environment interactions, and the pathways of disease (including the interplay between one disease and other conditions or diseases in the same patient)."

In the 2014 Science article, Oye and colleagues point to the potential ecological impact of using gene drives. An introduced trait could spread beyond the target population to other organisms through crossbreeding. Gene drives could also reduce the genetic diversity of the target population, potentially hampering its ability to survive.

Other ethical concerns are more nuanced. Should we make changes that could fundamentally affect future generations without having their consent? What if the use of germline editing veers from being a therapeutic tool to an enhancement tool for various human characteristics?

To address these concerns, the National Academies of Sciences, Engineering and Medicine put together a comprehensive report with guidelines and recommendations for genome editing.

Although the National Academies urge caution in pursuing germline editing, they emphasize "caution does not mean prohibition." They recommend that germline editing be done only on genes that lead to serious diseases and only when there are no other reasonable treatment alternatives. Among other criteria, they stress the need to collect data on the health risks and benefits and to maintain continuous oversight during clinical trials. They also recommend that, after a trial concludes, trial organizers should follow up with the participants' families for multiple generations to see what changes persist in the genome over time.
This article includes additional reporting by Alina Bradford, Live Science contributor. Originally published on Live Science.
Additional resources

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CRISPR is a powerful tool for editing genomes, meaning it allows researchers to easily alter DNA sequences and modify gene function. It has many potential applications, including correcting genetic defects, treating and preventing the spread of diseases, and improving the growth and resilience of crops. However, despite its promise, the technology also raises ethical concerns.

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The term cloning describes a number of different processes that can be used to produce genetically identical copies of a biological entity. The copied material, which has the same genetic makeup as the original, is referred to as a clone. Researchers have cloned a wide range of biological materials, including genes, cells, tissues and even entire organisms, such as a sheep.

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The term cloning describes a number of different processes that can be used to produce genetically identical copies of a biological entity. The copied material, which has the same genetic makeup as the original, is referred to as a clone.

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Many people first heard of cloning when Dolly the Sheep showed up on the scene in 1997. Artificial cloning technologies have been around for much longer than Dolly, though.

There are two ways to make an exact genetic copy of an organism in a lab: artificial embryo twinning and somatic cell nuclear transfer.

1. Artificial Embryo Twinning

Artificial embryo twinning is a relatively low-tech way to make clones. As the name suggests, this technique mimics the natural process that creates identical twins.

In nature, twins form very early in development when the embryo splits in two. Twinning happens in the first days after egg and sperm join, while the embryo is made of just a small number of unspecialized cells. Each half of the embryo continues dividing on its own, ultimately developing into separate, complete individuals. Since they developed from the same fertilized egg, the resulting individuals are genetically identical.

Artificial embryo twinning uses the same approach, but it is carried out in a Petri dish instead of inside the mother. A very early embryo is separated into individual cells, which are allowed to divide and develop for a short time in the Petri dish. The embryos are then placed into a surrogate mother, where they finish developing. Again, since all the embryos came from the same fertilized egg, they are genetically identical.

2. Somatic Cell Nuclear Transfer

Somatic cell nuclear transfer (SCNT), also called nuclear transfer, uses a different approach than artificial embryo twinning, but it produces the same result: an exact genetic copy, or clone, of an individual. This was the method used to create Dolly the Sheep.

What does SCNT mean? Let's take it apart:

Somatic cell: A somatic cell is any cell in the body other than sperm and egg, the two types of reproductive cells. Reproductive cells are also called germ cells. In mammals, every somatic cell has two complete sets of chromosomes, whereas the germ cells have only one complete set.

Nuclear: The nucleus is a compartment that holds the cell's DNA. The DNA is divided into packages called chromosomes, and it contains all the information needed to form an organism. It's small differences in our DNA that make each of us unique.

Transfer: Moving an object from one place to another. To make Dolly, researchers isolated a somatic cell from an adult female sheep. Next they removed the nucleus and all of its DNA from an egg cell. Then they transferred the nucleus from the somatic cell to the egg cell. After a couple of chemical tweaks, the egg cell, with its new nucleus, was behaving just like a freshly fertilized egg. It developed into an embryo, which was implanted into a surrogate mother and carried to term. (The transfer step is most often done using an electrical current to fuse the membranes of the egg and the somatic cell.)

The lamb, Dolly, was an exact genetic replica of the adult female sheep that donated the somatic cell. She was the first-ever mammal to be cloned from an adult somatic cell.

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Many people first heard of cloning when Dolly the Sheep showed up on the scene in 1997. Artificial cloning technologies have been around for much longer than Dolly, though. There are two ways to make an exact genetic copy of an organism in a lab: artificial embryo twinning and somatic cell nuclear transfer.

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Animal cloning is associated with a number of other medical and scientific applications, like the development of animal organs for human transplants, which is also called xeno-transplantation.

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Animal cloning is associated with a number of other medical and scientific applications, like the development of animal organs for human transplants, which is also called xeno-transplantation.

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When Dolly, the first cloned sheep came in the news, cloning interested the masses. Not only researchers but even common people became interested in knowing about how cloning is done and what pros and cons it has. Everyone became more curious about how cloning could benefit the common man. Most of us want to know the pros and cons of cloning, its advantages and its potential risks to mankind. Let us understand them.

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These Pros and Cons of Cloning are Both Fascinating and Scary

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Cloning is the process of creating a copy of a biological entity. In genetics, it refers to the process of making an identical copy of the DNA of an organism. Are you interested in understanding the pros and cons of cloning?

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In a world first, Chinese researchers have successfully cloned macaques using the same technique that yielded the famous clone Dolly the sheep. The milestone, published in Cell on Wednesday, marks the first time that primates have ever been cloned in such a manner.

The years-long effort, led by Chinese Academy of Sciences postdoctoral fellow Zhen Liu, culminated in the recent birth of two female macaques, Zhong Zhong and Hua Hua. The macaques' names are drawn from the word zhonghua, an adjective for the Chinese people.

The two macaques-eight weeks and six weeks old-are genetically identical, both clones of the same donor culture of fetal monkey cells. The young monkeys are reportedly healthy and currently live in an incubator.

The discovery potentially leads to a brave new world of biomedical research and will unquestionably spark debate over cloning another primate species: humans. Here's everything you need to know about these potentially controversial clones.

ARE THESE THE FIRST CLONED MONKEYS?

Technically, no. In 1999, researchers "cloned" a rhesus macaque by splitting an early-stage macaque embryo into multiple parts-in effect, creating artificial identical twins. Other research showed that monkey cells could be cloned to create lines of stem cells. However, these efforts yielded only cells confined to petri dishes, not fully developed monkeys.

"It's about time, because I thought it would never happen," says Shoukhrat Mitalipov, the head of Oregon Health and Science University's Center for Embryonic Cell and Gene Therapy. He wasn't involved with the study, but he worked on previous monkey-cloning efforts.

SO WHY IS THIS A BIG DEAL?

In 1996, Dolly the sheep became the first mammal cloned using a technique called somatic cell nuclear transfer. Unlike embryo splitting, which can only yield a few copies, this method can theoretically produce an indefinite number of clones from a single donor. This lets researchers craft customizable, genetically uniform populations of animals with potential for biomedical research.

Since then, scientists have cloned more than 20 species-from cows to rabbits to dogs-using this technique, but the Chinese effort marks the first time that non-human primates have been cloned successfully in the same way. This is a big deal, because the cloning technique in this study may apply to other primates such as humans. However, the study's authors stress that they have no intention of cloning humans.

HOW DOES THIS CLONING METHOD WORK?

In animals such as sheep and monkeys, individuals have a bundle inside every cell called a nucleus, which contains a copy of their distinct genetic code. Somatic cell nuclear transfer involves delicately transferring the nucleus from one animal's cell into another animal's egg.

They then chemically prod the egg into developing, as if it had been naturally fertilized. If this embryo reaches a certain stage of development, scientists can then implant it into the surrogate. If the procedure is successful, the surrogate will get pregnant and give birth to an animal that is genetically identical to the nucleus donor.

WHY DID IT TAKE SO LONG TO CLONE PRIMATES THIS WAY?

The full process isn't as simple as plucking a nucleus out of a skin cell, plugging it into an egg, and expecting it to form a flawless clone. As embryonic cells differentiate into skin, muscle, and other tissues, their DNA gets spooled, bunched up, and tagged so that only specific genes are expressed within any given cell type. It's a bit like reading a choose-your-own-adventure book, settling on a particular plot you like, and gluing together the pages you skipped.

To increase the odds of success, researchers must nudge the donor nucleus's DNA into resembling the DNA of a young embryo. Turning back this genetic clock requires complex chemical protocols that must be fine-tuned for individual species. In part, this is why monkey cloning long proved elusive. The team in China tried several versions of the method before one worked, says study coauthor Qiang Sun, director of the Nonhuman Primate Research Facility at the Chinese Academy of Sciences Institute of Neuroscience.

Sun's team temporarily bathed the clone eggs in trichostatin A, a compound that helped ensure the donor DNA didn't bunch up. They also prodded the eggs to make enzymes that snipped certain chemical tags off the donor DNA, freeing up locked embryonic genes. The researchers also tried creating clones from both adult and fetal cells, but only clones derived from fetal cells survived. It's thought that the fetal cells were less "hardened" into their cell types than the adult cells, but because the fetal cells were differentiated, they too required reprogramming.

WHY CLONE MONKEYS IN THE FIRST PLACE?

The researchers say that they want to use this technique to breed macaques for biomedical research. Exact genetic copies of the same animal would reduce the variability in results when testing new drugs or other therapies.

"For the cloning of primate species, including humans, the technical barrier is now broken," says study coauthor Mu-Ming Poo, who directs the Center for Excellence in Brain Science and Intelligence Technology at the Chinese Academy of Sciences. "However, the reason we chose to break this barrier is to produce animal models that are useful for human medicine. There's no intention to apply this method to humans."

Koen Van Rompay, a virologist at the California National Primate Research Center, thinks that such clones would be useful in the long run: "If there would be an efficient way to clone monkeys, that could actually reduce the number of monkeys needed to answer a certain research question," he says.

Van Rompay and Mitalipov caution, however, that the promised therapeutic benefits may not be right around the corner. For one, the technique doesn't strike them as particularly efficient. Of the team's 21 cloning attempts using fetal donor cells, only two resulted in healthy live births. What's more, Zhong Zhong and Hua Hua are only two months old. Researchers don't yet know what infirmities, if any, will afflict them later in life as a result of being cloned.

"This is just a step," says Van Rompay. "We are not ready to clone monkeys large-scale."

BUT IS IT ETHICAL TO MAKE CLONES?

The use of non-human primates as lab animals has long been contentious. Animal-welfare groups have cast experiments on non-human primates as cruel, exactly because of the animals' similarities to humans. They also express concern over cloning itself, pointing to miscarriages, sterile social environments, human hand-raising, and other unnatural stressors.

"It gives this sense that animals are disposable and commodities for us to use," says Kathleen Conlee, vice president of animal research issues at the Humane Society of the United States. "Is this appropriate, to have an animal you can do whatever you want to? ... It creates a poor dynamic about how we treat animals overall."

China, in particular, faces high scrutiny on matters of animal welfare because it has no comprehensive laws against animal cruelty. The study authors say that their facilities follow animal-welfare regulations set by the U.S. National Institutes of Health and that they are attentive to the macaques' welfare.

It's possible that improvements in genetics and computer modeling will limit the need for lab monkeys, says Eliza Bliss-Moreau, a behavioral neuroscientist at the California National Primate Research Center. "Technology has advanced so much in the last decade," she says. "Some of the questions that you would think of in behavioral neuroscience as being targets for [cloning], we're already tackling in other ways."

But many biomedical researchers insist that primate models are still necessary for studying complex human diseases and disorders, from Parkinson's to HIV/AIDS to autism. "I don't think there will ever be a way we can avoid non-human primates in biomedical research," says Van Rompay. "If that happens, that would be great, but right now, in-vitro and computer models are not sufficient."

Johns Hopkins University bioethicist Jeffrey Kahn, an expert on the use of primates in biomedical research, says that the questions this new study poses are complex: "Should we invest in this or organs on a chip? I don't think it's that simple."

WHAT DOES THIS MEAN FOR CLONING HUMANS?

In short, this study suggests that human cloning could be technically possible in a matter of months to years. "The genie's out of the bottle now," says Jose Cibelli, a cloning expert at Michigan State University who wasn't involved with this study.

Whether reproductive human cloning should proceed, however, is another question entirely. All of the scientists interviewed by National Geographic stressed that at present, human cloning would be unnecessary and irresponsible. "There's no reason to clone humans at this time," says Poo. "There must be international discussion on this issue."

Bioethicist Kahn urges a global discussion, as well: "What should we do about it-the 'we' being societies, countries, oversight bodies, governments?" he says. "What kind of governance do we think is necessary to prevent bad things from happening to humans, in the context of technology like this?"

WHAT'S NEXT?

The Chinese research team says that they will monitor the long-term health of Zhong Zhong and Hua Hua, including the pair's brain development. The coauthors also say that the government of Shanghai strongly supports their research and is underwriting plans to expand their laboratory by more than tenfold. In addition, they expressed hope that Chinese society-which is rapidly shifting its views on animal welfare-will keep an open mind to conducting research on non-human primates.

"With all this improvement, along with the high standards of ethical concerns, I think that Chinese society will accept this," says Poo. "I hope that societies in Western countries will realize once we demonstrate the cloned monkeys' usefulness in curing disease, they will gradually change their mind."

Editor's note: This article has been updated to clarify Kathleen Conlee's stance on cloning.

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Monkey Clones Created in the Lab. Now What?

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In a world first, Chinese researchers have successfully cloned macaques using the same technique that yielded the famous clone Dolly the sheep. The milestone, published in Cell on Wednesday, marks the first time that primates have ever been cloned in such a manner.

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In 2009 the Brazilian Agricultural Research Corp. (Embrapa) and the Brasilia Zoological Garden began scavenging and freezing blood, sperm and umbilical cord cells from roadkill and other wild animals that had died, mostly in the Cerrado savanna-an incredibly diverse collection of tropical forest and grassland ecosystems home to at least 10,000 plant species and more than 800 species of birds and mammals, some of which live nowhere else in the world. Specimens were collected from the bush dog, collared anteater, bison and gray brocket deer, among other species.

The idea was to preserve the genetic information of Brazil's endangered wildlife. One day, the organizations reasoned, they might be able to use the collected DNA to clone endangered animals and bolster dwindling populations. So far the two institutions have collected at least 420 tissue samples. Now they are collaborating on a related project that will use the DNA in these specimens to improve breeding and cloning techniques. Current cloning techniques have an average success rate of less than 5 percent, even when working with familiar species; cloning wild animals is usually less than 1 percent successful.

Any animals born during Brazil's new undertaking will live in the Brasilia Zoo, says Embrapa researcher Carlos Martins. Expanding captive populations of wild animals, he and his team hope, will discourage zoos and researchers from taking even more wild animals out of their native habitats. Martins and his colleagues have not yet decided which species they will attempt to clone but the maned wolf and jaguar are strong candidates. The International Union for Conservation of Nature classifies both animals as "near threatened" on its Red List of Threatened Species, two levels below "endangered."

Many researchers agree that, at present, cloning is not a feasible or effective conservation strategy. First of all, some conservationists point out, cloning does not address the reasons that many animals become endangered in the first place-namely, hunting and habitat destruction. Even if cloning could theoretically help in truly desperate situations, current cloning techniques are simply too ineffective to make much of a difference. Compared with cloning domestic species-particularly cattle, which have been successfully cloned for years to duplicate desirable traits-cloning endangered species is far more difficult for a number of reasons.

Successful cloning generally involves at least three essential components: DNA from the animal to be cloned; a viable egg to receive that DNA; and a mother to gestate the resulting embryo. Often, hundreds of embryos and attempted pregnancies are needed to produce even a few clones. Scientists usually have a poor understanding of endangered animals' reproductive physiology, which makes it too risky to extract a sufficient number of eggs from that species or rely on females of that species to give birth to clones. Legal protections sometimes preclude threatened species from such procedures as well. To compensate, researchers fuse the DNA of an endangered species with eggs from a closely related species and select mothers from the latter. Such hybrid embryos often fail to develop properly.

Although they are keenly aware of these problems, Martins and his colleagues, as well as a few other scientists around the world, think that efforts to archive the genetic information of endangered wildlife are worthwhile. Some researchers remain optimistic that cloning will become a useful tool for conservation in the future. Optimists point to recent successes cloning wild mammals using closely related domestic species, improved techniques for preventing developmental abnormalities in a cloned embryo, better neonatal care for newborn clones and in vitro fertilization made possible by stem cells derived from frozen tissue.

The first clones
In the early 1950s, at the Lankenau Hospital Research Institute in Philadelphia, Robert Briggs and Thomas King successfully cloned 27 northern leopard frogs through a process known as nuclear transfer. The nucleus, often called the command center of the cell, contains most of a vertebrate's DNA-except for the DNA within bean-shaped, energy-generating organelles named mitochondria. Briggs and King emptied frog eggs of their nuclei, sucked nuclei out of cells in frog embryos and injected those nuclei into the empty eggs. Many of the eggs developed into tadpoles that were genetically identical to the embryos that had donated their nuclear DNA.

In 1958 John Gurdon, then at the University of Oxford, and colleagues cloned frogs with nuclear DNA extracted from the cells of fully formed tadpoles. Unlike embryonic cells, which are genetically flexible enough to become a variety of different tissues, a tadpole's cells are "differentiated"-that is, the patterns of genes they express have changed to fit the profile of a specific cell type: a skin, eye or heart cell, for example. Gurdon demonstrated that, when transplanted into an egg, nuclear DNA from a mature cell reverts to the more versatile state characteristic of DNA in an embryo's cells. This breakthrough encouraged scientists to try cloning far larger animals using DNA from adult cells.

In 1996 researchers in Scotland attempted to clone a female Finn-Dorset sheep. They injected nuclei extracted from her udder cells into nearly 300 empty eggs derived from Scottish blackfaces, a different sheep breed. Out of those prepared eggs, the scientists managed to create more than 30 embryos. Only five of those embryos developed into lambs after being implanted in surrogate Scottish blackfaces. And only one of those lambs survived into adulthood. The researchers named her Dolly.

Since then some biologists have repeatedly suggested that cloning could help save endangered species, especially in dire situations in which only a few dozen or a handful of animals remain. The smaller, more homogenous and more inbred a population, the more susceptible it is to a single harmful genetic mutation or disease. Clones could theoretically increase the genetic diversity of an endangered population if researchers have access to preserved DNA from many different individuals. At the very least, clones could stabilize a shrinking population. And, some researchers argue, a genetically homogenous but stable population would be better than extinction; some highly inbred groups of wild animals, such as Chillingham cattle in England, have survived just fine for hundreds of years.

One species that might benefit from cloning is the northern white rhinoceros, which is native to Africa. In 1960 the global northern white rhino population was more than 2,000 strong, but poaching has reduced their numbers to as few as 11 today. By last count, three live in zoos-two in San Diego and one in the Czech Republic-four live in the Ol Pejeta Conservancy in Kenya and as few as four individuals may still live in the wild based on unconfirmed reports, but they have not been spotted in several years. Most of the captive animals are uninterested in mating or infertile, although two rhinos mated in the summer of 2012.

Right now, though, cloning is unlikely to help the white rhino or any other threatened species. To date, the story of cloning endangered animals is one of a few high-profile successes and many, many failures. Since the early 2000s, using the same technique that produced Dolly, researchers have cloned several endangered and even extinct mammals, including a mouflon sheep and a bovine known as a gaur in 2001; a kind of wild cattle called a banteng in 2003; a wild goat known as the Pyrenean ibex in 2009; and wild coyotes in 2012. In each case many more clones died before birth than survived; in most cases none of the clones survived into adulthood.

Mismatched
All those attempted clones of endangered or extinct animals died in different ways for different reasons, but they all shared one fundamental problem-they were not exact replicas of their counterparts. In most cases, researchers have combined DNA from the threatened species with eggs from a related domestic species. Each surrogate mother is often implanted with dozens of hybrid embryos in order to achieve at least a few pregnancies, a strategy that requires extracting hundreds of eggs. Because the reproductive physiology of most endangered animals is so poorly understood, researchers are often unsure when the animals ovulate and how best to acquire their eggs. In some cases legal protections prevent scientists from harvesting eggs from threatened species. For all these reasons, they turn to more familiar domestic species instead.

Injecting the DNA of one species into the egg of another species-even a closely related one-creates an unusual hybrid embryo that often fails to develop properly in the womb of a surrogate mother. Hybrid embryos have the nuclear DNA of the cloned species and the mitochondrial (mtDNA) DNA of the donor egg. This mismatch becomes problematic as the embryo develops. Nuclear DNA and mtDNA work together; they both contain genetic recipes for proteins with which cells extract energy from food. In a hybrid embryo these proteins do not always fit together properly, which leaves cells starved for energy. Complicating matters further, the surrogate mother often rejects the hybrid embryo because she recognizes some of the embryo's tissues, particularly the placenta, as foreign.

Another problem-and the most intractable so far-is that a hybrid embryo created via nuclear transfer is not a genetic blank slate like most embryos. All vertebrates begin life as hollow balls of embryonic stem cells, which can become almost any type of adult cell. Each of those stem cells contains a copy of the exact same genome packaged into chromosomes-tight bundles of DNA and histone proteins. As the embryo develops, the stem cells begin to take on their adult forms: some become skin cells, others heart cells and so on. Different types of cells begin to express different patterns of genes. Inside each cell an assortment of molecules and enzymes interacts with DNA and histones to change gene expression. Some molecules, such as methyl groups, physically block cellular machinery from reading the genetic instructions in certain segments of DNA; some enzymes loosen the bonds between histones and DNA, making particular genes more accessible. Eventually, each cell type-skin cell, liver cell, brain cell-has the same genome, but a different epigenome: a unique pattern of genes that are actively expressed or effectively silenced. Over time, an adult cell's epigenome can change even further, depending on the animal's life experiences.

So when researchers inject an adult cell's nucleus into an empty egg, the nucleus brings its unique epigenome with it. As Gurdon's early experiments in the 1950s and subsequent studies have shown, an egg is capable of erasing the epigenome of introduced nuclear DNA, wiping the slate clean-to some extent. This process of "nuclear reprogramming" is poorly understood, and the egg often fails to complete it properly, especially when the egg is from one species and the nuclear DNA from another. Incomplete nuclear reprogramming is one of the main reasons, scientists think, for the many developmental abnormalities that kill clones before birth and for the medical issues common to many survivors, such as extremely high birth weight and organ failure.

Some researchers see ways around these problems. Pasqualino Loi of the University of Teramo in Italy was part of a team that successfully cloned endangered mouflon sheep in the early 2000s; the clones died within six months of birth. Loi and his colleagues think they can increase the chances of a hybrid embryo surviving in a surrogate mother's womb. First, they propose, researchers could nurture a hybrid embryo for a short time in the lab until it develops into what is known as a blastocyst-the ball-shaped beginnings of a vertebrate composed of an outer circle of cells, the trophoblast, surrounding a clump of rapidly dividing stem cells known as the inner cell mass. Eventually, the trophoblast becomes the placenta. Researchers could scoop out the inner cell mass from the hybrid blastocyst, Loi suggests, and transplant it into an empty trophoblast derived from the same species as the surrogate mother. Because the surrogate mother is far less likely to reject a trophoblast from her own species, the developing embryo within has a much better chance of surviving.

Scientists have also figured out how to encourage nuclear reprogramming by bathing the egg in certain compounds and chemicals, such as trichostatin A, which stimulate or inhibit the enzymes that determine a cell's epigenome. Most recently, Teruhiko Wakayama of the RIKEN Center for Developmental Biology in Kobe, Japan and his colleagues produced 581 cloned mice from a single donor mouse over 25 generations, using trichostatin A to achieve success rates as high as 25 percent in some but not all generations. To solve the mismatch of mtDNA and nuclear DNA, Loi suggests simply removing the egg's native mtDNA and replacing it with mtDNA from the species to be cloned-something that researchers tried in the 1970s and '80s, but have not attempted recently for reasons that are unclear.

Some of the most successful attempts to clone endangered animals in recent years have involved two of the most beloved domestic species-cats and dogs. At the Audubon Center for Research of Endangered Species in New Orleans, Martha Gomez and her colleagues have created many African wildcat clones since the mid-2000s, using domestic cats as surrogate mothers. Gomez says eight clones have survived into adulthood so far and are all healthy today. She attributes her success, in part, to the fact that wildcats and domestic cats are much more closely related to each other than are most wild and domestic species paired for the purpose of cloning. She and her team have also learned to increase success rates with caesarian sections-to spare clones the stress of a typical birth-and to keep newborn clones in intensive care for a few weeks, as though they were premature babies. In 2008, B. C. Lee of Seoul National University in Korea and his colleagues achieved similar success using domestic dogs to create three healthy male gray wolf clones. Lee's team had previously created two female gray wolf clones. All five animals survived into adulthood, Lee confirms.

Working with black-footed cats, which are native to Africa and listed as "Vulnerable" on the Red List, Gomez is now focusing on a method of cloning that differs from nuclear transfer. She is trying to transform adult cells from black-footed cats into stem cells and subsequently induce those stem cells to become sperm and eggs. Then, through in vitro fertilization or similar techniques, she could impregnate domestic cats with black-footed cat embryos. Alternatively, stem cell-derived sperm and eggs could be used to impregnate females of the endangered species.

To say that this approach is technically challenging would be an understatement, but researchers have made impressive progress. In 2011 Jeanne Loring of the Scripps Research Institute in La Jolla, Calif., and her colleagues produced stem cells from the frozen skin cells of two endangered species-the northern white rhino and a baboonlike primate known as a drill. And in 2012 Katsuhiko Hayashi of Kyoto University Graduate School of Medicine and colleagues turned skin cells from adult mice into stem cells, which they then transformed into viable eggs. After fertilizing the eggs with sperm in test tubes, the researchers implanted the embryos in surrogate mother mice that gave birth to healthy and fertile offspring.

"I'm not saying cloning is going to save endangered species," Gomez says, "but I am still a believer of cloning as another tool. It's not easy, though. The research moves slow."

Teramo's Loi remains optimistic too. He thinks that scientists should continue to collect and preserve the genetic information of endangered animals, as Brazil has done, creating bio-banks of tissue on ice, such as the "frozen zoo" at the San Diego Zoo's Institute for Conservation Research. If researchers manage to dramatically increase the efficiency of cloning wild and endangered animals-whether with nuclear transfer or in vitro fertilization-then the DNA they need will be waiting for them. If they do not, bio-banks will still be useful for more basic research. "Once cloning of endangered animals is properly established, it will be a very powerful tool," Loi says. "If something can be done, it will be done in 10 years."

ABOUT THE AUTHOR(S)

Ferris Jabr is a contributing writer for Scientific American. He has also written for the New York Times Magazine, the New Yorker and Outside. Follow Ferris Jabr on Twitter Credit: Nick Higgins

Recent Articles by Ferris Jabr

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Will Cloning Ever Save Endangered Animals?

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In 2009 the Brazilian Agricultural Research Corp. (Embrapa) and the Brasilia Zoological Garden began scavenging and freezing blood, sperm and umbilical cord cells from roadkill and other wild animals that had died, mostly in the Cerrado savanna-an incredibly diverse collection of tropical forest and grassland ecosystems home to at least 10,000 plant species and more than 800 species of birds and mammals, some of which live nowhere else in the world.

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Making Fruits and Vegetables more exciting to eat.

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Forget vegetables with dull colors and fuzzy skin or fruits that lack of flavor -- the produce aisle of the future could offer plant products that are designed for creative cooks and fussy eaters. In a review article published July 19 in the journal Trends in Plant Science, two food researchers describe how new breeding technologies have the potential to enhance the shape, size, color, and health benefits of produce, as well as to inform conventional breeding programs.

"Novelty drives a lot of first time purchasing," says Andrew Allan of New Zealand science institute Plant & Food Research, who co-wrote the article with Richard Espley. "If the experience is good, then the consumer will purchase again. Choice is key -- there is no risk with more choice."

In their review, the authors describe how fast breeding with CRISPR-Cas9 gene editing doesn't rely on the addition of a new DNA sequence as is often the case with other genetically modified crops. Rather, these breeding technologies allow scientists to edit existing genes, particularly transcription factor genes called MYBs, which control many of a plant's key consumer traits. Information from these experiments can also be used to inform selection criteria in conventional breeding programs.

"MYBs often regulate the compounds that generate a fruit or vegetables' 'wow' factor -- its color," Allan says. "These compounds are also associated with important health benefits such as lowering cardiovascular disease or acting as vitamins. By using MYBs to elevate these compounds to create a richer color, we can make produce both more appealing to consumers and more beneficial for the human diet."

This works for changes below the surface, as well. For example, apples and potatoes have colorless flesh, which often means that nutrients are concentrated in the skin. By altering MYBs to produce higher quantities of compounds in the flesh of the apple or potato, scientists can create fruits and vegetables where every bite has the same concentration of vitamins.

The technology is also being used to adjust flavor and texture, and Allan is excited by what this progress could mean for the future of our supermarkets. He even suggests that this could usher in "the next green revolution, with more product choice for developed countries, greater yields for less developed countries, and more growing options for climate resilience." To those who may have reservations, he says new breeding techniques emulate changes to DNA made in nature and can be used to advance conventional breeding and growing practices.

The authors receive support from the New Zealand Government, Ministry of Business, Innovation and Employment Endeavour Funds, 'Turbo Breeding' and 'Filling the Void.'

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food; agriculture and food; genetics; botany; retail and services; environmental policies; consumerism; public health

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How plant breeding technologies could make fruits and vegetables more exciting to eat

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Forget vegetables with dull colors and fuzzy skin or fruits that lack of flavor -- the produce aisle of the future could offer plant products that are designed for creative cooks and fussy eaters.

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In a world first, scientists have used gene editing to successfully repair a disease-causing mutation in human embryos, which is an achievement that marks a major step forward for the prevention of inherited diseases.

Scientists have used CRISPR-Cas9 to repair a mutation in human embryos.

In a study recently published in the journal Nature, an international team of researchers reveal how they used CRISPR-Cas9 gene editing on newly fertilized eggs to repair a mutated MYBPC3 gene known to cause hypertrophic cardiomyopathy (HCM).

HCM is a condition characterized by the thickening of the heart muscle. According to the American Heart Association (AHA), HCM is estimated to affect up to half a million people in the United States, and it is a common cause of sudden cardiac death, particularly among young athletes.

An inherited mutation of the MYBPC3 gene accounts for up to 30 percent of familial HCM cases; individuals with one copy of this gene mutation have a 50 percent chance of passing it to their offspring.

In recent years, scientists have looked to gene editing as a way of eliminating disease-causing mutations. One type of gene editing technique that has gained momentum is CRISPR-Cas9, which involves adding, removing, or modifying sequences of DNA to influence the function of a gene.

While CRISPR-Cas9 has demonstrated success in animal models, there have been ethical concerns about its use in humans. In particular, critics have cautioned that the technique may be exploited for non-therapeutic purposes, such as creating "designer babies."

What is more, there is a worry that in using CRISPR-Cas9 to repair one disease-causing mutation in human embryos, other potentially harmful mutations may be unintentionally introduced.

However, scientists from China, South Korea, and the U.S. have become the first to successfully repair the MYBPC3 gene mutation in human embryos using CRISPR-Cas9, without any unintended consequences.

Mutations repaired in 72 percent of embryos

Using in vitro fertilization, the researchers injected sperm retrieved from men with an MYBPC3 gene mutation into eggs retrieved from healthy women.

Unlike in previous studies, the researchers applied CRISPR-Cas9 to the healthy eggs at the same time as they injected the sperm. According to the team, this process helps to reduce "mosaicism," whereby some of the mutated cells in an embryo are repaired and some are not.
The researchers found that the CRISPR-Cas9 technique edited the DNA at the correct position for 100 percent of the embryos, and MYBPC3 gene mutations were fully repaired in 42 out of 58 embryos tested, representing a success rate of 72.4 percent.
"Our technology successfully repairs the disease-causing gene mutation by taking advantage of a DNA repair response unique to early embryos," says co-first study author Jun Wu, of the Salk Institute for Biological Studies in La Jolla, CA.

Specifically, the researchers found that the gene editing technique used DNA from the healthy eggs as a "template," which helped to identify the location of DNA mutations in sperm that needed repairing.

Next, the team used whole-genome sequencing on the edited embryos to determine whether or not CRISPR-Cas9 had induced any unwanted changes to the genome. The researchers found no such changes.

In essence, the study provides the first evidence that CRISPR-Cas9 could be used to repair MYBPC3 gene mutations and prevent the development of familial HCM.

"Every generation on would carry this repair because we've removed the disease-causing gene variant from that family's lineage," says senior study author Shoukhrat Mitalipov, Ph.D., of Oregon Health & Science University (OHSU) in Portland. "By using this technique, it's possible to reduce the burden of this heritable disease on the family and eventually the human population."

Ethical concerns remain

This groundbreaking study does not only offer the hope of a cure for HCM, however. Researchers believe that it represents a major advancement in the use of gene editing for a wealth of hereditary diseases.

"This research significantly advances scientific understanding of the procedures that would be necessary to ensure the safety and efficacy of germline gene correction."

Daniel Dorsa, Ph.D., senior vice president for research at OHSU

That said, Wu and colleagues caution that further research is needed before clinical trials can be conducted, and many ethical concerns remain.

"Gene editing is still in its infancy so even though this preliminary effort was found to be safe and effective, it is crucial that we continue to proceed with the utmost caution, paying the highest attention to ethical considerations," says study co-author Juan Carlos Izpisua Belmonte, also of the Salk Institute for Biological Studies.

"The ethical considerations of moving this technology to clinical trials are complex and deserve significant public engagement before we can answer the broader question of whether it's in humanity's interest to alter human genes for future generations," adds Dorsa.

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Breakthrough: Gene editing repairs mutation in human embryos

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In a world first, scientists have used gene editing to successfully repair a disease-causing mutation in human embryos, which is an achievement that marks a major step forward for the prevention of inherited diseases. Scientists have used CRISPR-Cas9 to repair a mutation in human embryos.

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Plants

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Rediscovering Biology - Online Textbook: Unit 13 Genetically Modified Organisms

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Teacher resources and professional development across the curriculum

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Pros and Cons

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On November 25, 2018, geneticist He Jiankui of China's Southern University of Science and Technology announced that his lab had successfully used the Crispr-Cas9 gene-editing system to make the world's first genetically edited human babies. Outside scientists haven't verified his claims, and his home university is planning to investigate him for academic violations. But if the results hold, the experiment would mark a scientific milestone- and raise profound ethical issues. In the August 2016 issue of National Geographic magazine, we invited contributors to weigh the ethics of making edits to the human genome that future generations would inherit.

Pro: Research on Gene Editing in Humans Must Continue
By John Harris
John Harris is professor emeritus in science ethics at University of Manchester, U.K., and the author of How to be Good, Oxford University Press 2016.

In February of this year, the Human Fertilization and Embryology Authority in the United Kingdom approved a request by the Francis Crick Institute in London to modify human embryos using the new gene editing technique CRISPR-Cas9. This is the second time human embryos have been employed in such research, and the first time their use has been sanctioned by a national regulatory authority. The scientists at the Institute hope to cast light on early embryo development-work which may eventually lead to safer and more successful fertility treatments.

The embryos, provided by patients undergoing in vitro fertilization, will not be allowed to develop beyond seven days. But in theory-and eventually in practice-CRISPR could be used to modify disease-causing genes in embryos brought to term, removing the faulty script from the genetic code of that person's future descendants as well. Proponents of such "human germline editing" argue that it could potentially decrease, or even eliminate, the incidence of many serious genetic diseases, reducing human suffering worldwide. Opponents say that modifying human embryos is dangerous and unnatural, and does not take into account the consent of future generations. Who is right?

Let's start with the objection that embryo modification is unnatural, or amounts to playing God. This argument rests on the premise that natural is inherently good. But diseases are natural, and humans by the millions fall ill and die prematurely-all perfectly naturally. If we protected natural creatures and natural phenomena simply because they are natural, we would not be able to use antibiotics to kill bacteria or otherwise practice medicine, or combat drought, famine, or pestilence. The health care systems maintained by every developed nation can aptly be characterized as a part of what I have previously called "a comprehensive attempt to frustrate the course of nature." What's natural is neither good nor bad. Natural substances or natural therapies are only better that unnatural ones if the evidence supports such a conclusion.

The matter of consent has been raised by Francis Collins, director of the National Institutes of Health. "Ethical issues presented by altering the germline in a way that affects the next generation without their consent," he has said, constitute "strong arguments against engaging in" gene editing.

This makes no sense at all. We have literally no choice but to make decisions for future people without considering their consent. All parents do this all the time, either because the children are too young to consent, or because they do not yet exist. George Bernard Shaw and Isadora Duncan knew this. When, allegedly, she said to him "why don't we make a baby together ... with my looks and your brains it cannot fail" she was proposing a deliberate germline determining decision in the hope of affecting their future child. Shaw's more sober response-"Yes but what if it has my looks and your brains!"-identifies a different possible, but from the child's perspective equally non-consensual, outcome. Rightly, neither Shaw nor his possible partner thought their decision needed to wait for the consent of the resulting child.

Needless to say, parents and scientists should think responsibly, based on the best available combination of evidence and argument, about how their decisions will affect future generations. However, their decision-making simply cannot include the consent of the future children.

Finally, there's the argument that modifying genomes is inherently dangerous because we can't know all the ways it will affect the individual. But those who fear the risks of gene editing don't take into account the inherent dangers in the "natural" way we reproduce. Two-thirds of human embryos fail to develop successfully, most of them within the first month of pregnancy. And every year, 7.9 million children-6 percent of total births worldwide-are born with a serious defect of genetic or partially genetic origin. Indeed so risky is unprotected sex that, had it been invented as a reproductive technology rather than found as part of our evolved biology, it is highly doubtful it would ever have been licensed for human use.

Certainly we need to know as much as possible about the risks of gene-editing human embryos before such research can proceed. But when the suffering and death caused by such terrible single-gene disorders as cystic fibrosis and Huntington's disease might be averted, the decision to delay such research should not be made lightly. Just as justice delayed is justice denied, so, too, therapy delayed is therapy denied. That denial costs human lives, day after day.

Con: Do Not Open the Door to Editing Genes in Future Humans
By Marcy Darnovsky
Marcy Darnovsky, Ph.D., is executive director of the Center for Genetics and Society. She speaks and writes on the politics of human biotechnology.

The gene editing tool known as CRISPR catapulted into scientific laboratories and headlines a few short years ago. Fast on its heels came the reemergence of a profoundly consequential controversy: Should these new techniques be used to engineer the traits of future children, who would pass their altered genes to all the generations that follow?

This is not an entirely new question. The prospect of creating genetically modified humans was openly debated back in the late 1990s, more than a decade and a half before CRISPR came on the scene and several years before the human genome had been fully mapped.

It wasn't long before we saw provocative headlines about designer babies. Princeton mouse biologist Lee Silver, writing in Time magazine in 1999, imagined a fertility clinic of the near future that offered "Organic Enhancement" for everyone, including people with "no fertility problems at all." He even wrote the ad copy: "Keep in mind, you must act before you get pregnant. Don't be sorry after she's born. This really is a once-in-a-lifetime opportunity for your child-to-be."

During the same millennial shift, policymakers in dozens of countries came to a very different conclusion about the genetic possibilities on the horizon. They wholeheartedly supported gene therapies that scientists hoped (and are still hoping) can safely, effectively, and affordably target a wide a range of diseases. But they rejected human germline modification-using genetically altered embryos or gametes to produce a child-and in some 40 countries, passed laws against it.

The issue of human germline modification stayed on a slow simmer during the first decade of the 21st century. But it roared to a boil in April 2015, when researchers at Sun Yat-sen University announced they had used CRISPR to edit the genomes of nonviable human embryos. Their experiment was not very successful in technical terms, but it did focus the world's attention.

In December 2015, controversy about using CRISPR to produce children was a key agenda item at the International Summit on Human Gene Editing organized by the national science academies of the United States, the United Kingdom, and China. Nearly every speaker agreed that at present, making irreversible changes to every cell in the bodies of future children and all their descendants would constitute extraordinarily risky human experimentation. By all accounts, far too much is unknown about issues including off-target mutations (unintentional edits to the genome), persistent editing effects, genetic mechanisms in embryonic and fetal development, and longer-term health and safety consequences.

Conversations about putting new gene editing tools into fertility clinics need to begin with an obvious but often overlooked point: By definition, germline gene editing would not treat any existing person's medical needs. At best, supporters can say that it might re-weight the genetic lottery in favor of different outcomes for future people-but the unknown mechanisms of both CRISPR and human biology suggest that unforeseeable outcomes are close to inevitable.

Beyond technical issues are profound social and political questions. Would germline gene editing be justifiable, in spite of the risks, for parents who might transmit an inherited disease? It's certainly not necessary. Parents can have children unaffected by the disease they have or carry by using third-party eggs or sperm, an increasingly common way to form families. Some heterosexual couples may hesitate to use this option because they want a child who is not just spared a deleterious gene in their lineage, but is also genetically related to both of them. They can do that too, with the embryo screening technique called pre-implantation genetic diagnosis (PGD), a widely available procedure used in conjunction with in vitro fertilization.

PGD itself raises social and ethical concerns about what kind of traits should be selected or de-selected. These questions are particularly important from a disability rights perspective (which means they're important for all of us). But screening embryos for disease is far safer for resulting children than engineering new traits with germline gene editing would be. Yet this existing alternative is often omitted from accounts of the controversy about gene editing for reproduction.

It is true that a few couples-a very small number-would not be able to produce unaffected embryos, and so could not use PGD to prevent disease inheritance. Should we permit germline gene editing for their sake? If we did, could we limit its use to cases of serious disease risk?

From a policy perspective, how would we draw the distinction between a medical and enhancement purpose for germline modification? In which category would we put short stature, for example? We know that taller people tend to earn more money. So do people with paler skins. Should arranging for children with financially or socially "efficient" varieties of height and complexion be considered medical intervention?

Think back to the hypothetical fertility clinic offering "Organic Enhancement" as a "once-in-a-lifetime opportunity for your child-to-be." Think back to the 1997 movie Gattaca, about a society in which the genetically enhanced-merely perceived to be biologically superior-are born into the physical reality of those whom we might now call the one percent. These are fictional accounts, but they are also warnings of a possible human (or not so human) future. The kinds of social changes they foresee, once set in motion, could be as difficult to reverse as the genetic changes we're talking about.

In opening the door to one kind of germline modification, we are likely opening it to all kinds. Permitting human germline gene editing for any reason would likely lead to its escape from regulatory limits, to its adoption for enhancement purposes, and to the emergence of a market-based eugenics that would exacerbate already existing discrimination, inequality, and conflict. We need not and should not risk these outcomes.

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Pro and Con: Should Gene Editing Be Performed on Human Embryos?

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On November 25, 2018, geneticist He Jiankui of China's Southern University of Science and Technology announced that his lab had successfully used the Crispr-Cas9 gene-editing system to make the world's first genetically edited human babies. Outside scientists haven't verified his claims, and his home university is planning to investigate him for academic violations.

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In Jap

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Japan has issued draft guidelines that allow the use of gene-editing tools in human embryos. The proposal was released by an expert panel representing the country's health and science ministries on 28 September.

Although the country regulates the use of human embryos for research, there have been no specific guidelines on using tools such as CRISPR-Cas9 to make precise modifications in their DNA until now.

Tetsuya Ishii, a bioethicist at Hokkaido University in Sapporo, says that before the draft guidelines were issued, Japan's position on gene editing in human embryos was neutral. The proposal now encourages this kind of research, he says.

But if adopted, the guidelines would restrict the manipulation of human embryos for reproduction, although this would not be legally binding.

Manipulating DNA in embryos could reveal insights into early human development. Researchers also hope that in the long term, these tools could be used to fix genetic mutations that cause diseases, before they are passed on.

But the editing of genes in human embryos, even for research, has been controversial. Ethicists and many researchers worry that the technique could be used to alter DNA in embryos for non-medical reasons. Many countries ban the practice, allowing gene-editing tools to be used only in non-reproductive adult cells.

Researchers around the world have published at least eight﻿ studies on gene editing in human embryos. Some of the work was done in China and the United States, where using the technique does not break any laws if done with private funding; some was done in the United Kingdom, where permission must be granted by a national regulatory body.

Japan's draft guidelines will be open for public comment from next month and are likely to be implemented in the first half of next year.

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Japan set to allow gene editing in human embryos

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Japan has issued draft guidelines that allow the use of gene-editing tools in human embryos. The proposal was released by an expert panel representing the country's health and science ministries on 28 September. Although the country regulates the use of human embryos for research, there have been no specific guidelines on using tools such as CRISPR-Cas9 to make precise modifications in their DNA until now.

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CRISPER

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Gene editing in human development: ethical concerns and practical applications

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The amazing power of CRISPR-Cas9 gene editing tools and other related technologies has impacted all areas of biology today. It has also raised ethical concerns, particularly with regard to the possibility of generating heritable changes in the human genome - so-called germline gene editing.

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Animal Husbandry:

Animal husbandry is a branch of agriculture concerned with the care and management of livestock. Animal husbandry deals with the feeding, breeding, housing and health care of livestock for getting maximum benefits.

Livestock refers to farm animals (domesticated animals) such as cow, sheep, etc. kept by humans for a useful commercial purpose. When we use the word "Animal" in animal husbandry, we mean only those domesticated animals which are reared mostly for economic or for recreation purposes, such as cattle, buffalo, sheep, goat, camel, pig, horse, etc. It also includes poultry farming and fisheries.

Fisheries include rearing, catching, selling, etc. of fish, molluscs (shell fish) and crustaceans (Fresh water prawn- Palaemon, Crabs, etc.). Since long time, animals like bees and silkworm, have been used by humans. Livestock has been used by humans for products like milk, eggs, meat, wool, silk, honey, etc.

More than 70 per cent of the world livestock population is in India and China. But it is interesting to note that the contribution to the world farm produce is only 25 per cent. Hence in addition to old practices of animal breeding and care, new techniques have to be used to improve quality and productivity.

The word 'husbandry' means the management of domestic affair. The term used in connection with animal husbandry includes proper feeding, breeding, health care, housing, etc.

Role of Animal Husbandry in Human Welfare:
1. Dairy Products:
Mammalian livestock can be used as a source of milk and dairy products such as yoghurt, cheese, butter, ice cream, etc.
2. Meat:
It is the production of a useful form of dietary protein and energy.
3. Land management:
The grazing of livestock is sometimes used as a way to control weeds and undergrowth. For example, in areas prone to wild fires, goats and sheep are set to graze on dry shrub which reduces the risk of fires.
4. Fibre:
Livestock produce a range of fibre/textiles. For example, sheep and goats produce wool and deer and sheep can make leather.
5. Labour:
Animals such as horses, donkey and yaks can be used for mechanical energy. Prior to steam power, livestock were the only available source of non-human labour. They are still used for this purpose in many places of the world, including ploughing fields, transporting goods and military functions.
6. Fertilizer:
Manure can be spread on fields to increase crop yields. This is an important reason why historically, plant and animal domestication have been intimately linked. Manure is also used to make plaster for walls and floors and can be used as a fuel for fires. The blood and bones of animals are also used as fertilizer.

Management of Farm and Farm Animals:

Management is the art and science of combining ideas, facilities, processes, materials and labour to produce and market a worthwhile product or service successfully. Some of the management procedures in various animal farm systems are described below.

(1) Dairy Farm Management:

Dairying is the management of animals for milk and its products for human consumption. Cows, buffaloes, goats and sheep are the animals that we would expect in a dairy. Cows and buffaloes generally give more milk than goats and sheep. The yellow colour of cow milk is due to the carotene.

Buffalo milk does not contain carotene. Ghee from cow fed on an abundant green fodder is more yellow than when fed on dry food. In dairy management, the people deal with processes and systems that increase yield and improve quality of milk. These are described below.
1. Four essential methods for livestock improvement:
These are breeding, weeding, feeding and heeding, (i) Both the male and female animals selected for breeding should be of superior quality, (ii) Weeding aims that uneconomic animals must be prevented from reproducing, (iii) Feeding is also very important for animals. Each animal should be fed on a balance ration, (iv) Heeding (pay attention to) implies good animal management and general supervision including housing care and maintenance of proper cleanliness and hygiene.
2. Health Care:
According to WHO 'health' is the state of complete physical, mental and social well being and not merely the absence of disease. A healthy animal eats drinks and sleeps well regularly. Therefore, good health is important.
3. Suitable Environmental Conditions:
Adequate ventilation, suitable temperature, sufficient light, water, air and well-drained housing accommodation should be provided.
4. Resistance to Diseases:
If the animal is well looked after, the resistance to diseases develops and animal is protected from the diseases.
5. Regular Inspections:
The above mentioned measures would of course, require regular inspections, with proper record keeping. Regular visits by veterinary doctor would be necessary.

Thus the productive potentialities of live stock are controlled by three principle factors; (i) genetic makeup (ii) nutrition and (iii) environment including the climatic conditions. "Father of white revolution in India" is Verghese Kurein.

(2) Poultry Farm Management:

The word 'poultry' is used for birds which can be raised under domestication for economic purpose. The term applies to chickens, turkeys, ducks, geese, swans, guinea fowls, pigeons, peafowls and quails. In our country, it mainly means chickens, domesticated for eggs and meat. Ducks are also domesticated but to a much less extent.

Poultry farm management includes the following components.
1. Selection of Disease Free and Suitable Breeds:
Selection of breeds is the most important aspect. The breed should be disease free and suitable to the environmental conditions. The most common egg-type variety used for commercial production throughout the world is Single Comb White Leghorn and its various strains. The meat type stocks mainly originated from Plymouth Rock, Cornish and New Hampshire breeds of fowls.
2. Brood House:
Brooder house should be crowd-free, rain proof and protected from predators. It should have windows with wire mesh for adequate ventilation.
3. Sanitation and Hygiene:
The house should be cleaned and disinfected. Good drainage system is essential to keep the poultry yard clean.
4. Care of Chicks during Brooding:
On the arrival of chicks sweet water (gur 50 g/ litre) is given. The feed in the form of maize dalia should be given in the first 24-28 hours, but later on complete chick feed should be added to the feeders. Additional vitamins should be given in water during the first week.
5. Feed Management:
Feeding constitutes the major management concern in egg and meat production. The groups of nutrients are proteins, carbohydrates, fats, minerals and vitamins.
6. Light Management:
Light is essential for high egg production. 14 to 16 hours of light including daylight is required for optimum production.
7. Summer Management:
The birds have thick feather covering and do not have sweat glands. The birds can withstand cold, but are more sensitive to heat.
8. Winter Management:
Try to maintain the temperature above 15.5° C. Thus right temperature should be maintained.
Breeds:
Some breeds of Chicken are given below.

Desi(Indigenous Breeds)American Breeds English Breeds
Poultry Diseases and their Control:
The following are some of the important diseases of the poultry (i) Viral diseases : Ranikhet disease (New Castle disease), fowl-pox, infectious bronchitis, Marck's disease, chronic respiratory diseases, duck virus enteritis, hepatitis, Bird flu. (ii) Bacterial diseases: Fowl cholera, coryza, typhoid, paratyphoid, Pollorum disease, Salmonellosis, (iii) Protozoanal diseases: Coccidiosis, Spirochaetosis (tick fever). (iv) Fungal diseases: Aspergillosis (brooder pneumonia), mycosis, Aflatoxicosis- is also fungal disease in poultry which reduces immunity and spreads through contaminated food. (v) Parasites (a) External parasites : Lice, mites ticks and fleas (b) Internal parasites: Roundworms, tapeworm, threadworms, (vi) Nutritional diseases : Avitaminosis, rickets, perosis.

An outbreak of diseases like Ranikhet, Coryza or fowl cholera can lead to the death of a large number of birds. However, these and other diseases can now be controlled by preventive measures like good management, proper nutrition, and timely vaccination of the newly born chicks. Administration of sulpha drugs and broad spectrum antibiotic treatment also helps in curing several diseases.

It is also necessary to avoid overcrowding of birds, poor ventilation and dampness in poultry houses as these favour the spread of diseases. The immediate separation of the infected birds from the healthy ones and seeking veterinary aid is recommended to check the spread of the disease and its cure.
How to prevent the spread of 'bird flu virus'?
Bird flu is caused by a virus H5N1. All sick birds suspected of the disease must be separated from healthy birds. There must be proper disposal of dead birds and excreta. The houses are to be disinfected. The general procedure for control of infectious diseases should be followed. Complete removal of infected flock from the farm premises must be done and new flock may be introduced. Burn or bury the dead birds that die of the disease. Discourage visitors to poultry house. They can introduce infection.

Advantages of Poultry Farming:

Poultry farming has the following advantages.
1. Food:
It provides eggs and meat which are highly nutritious foods. They are a rich source of animal protein, minerals, right kind of fat and vitamins (A, В and D) for good health. Unfertilized eggs are called "vegetarian eggs".
2. Economic Uplift:
By selling the eggs and meat of these birds, the farmers become economically better. Poultry farming provides employment to a large number of people.
3. Manure:
The faecal matter of birds form a rich manure which increases the fertility of soil. It increases crop yields.
4. Feathers:
Feathers of the birds are useful.
5. Recreation:
The birds of poultry are also a means of recreation. Coloured chickens give pleasure look. Cock-fighting is popular in some people.

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Animal Husbandry: Role of Animal Husbandry in Human Welfare Management

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ADVERTISEMENTS: Role of Animal Husbandry in Human Welfare Management! Animal Husbandry: Animal husbandry is a branch of agriculture concerned with the care and management of livestock. Animal husbandry deals with the feeding, breeding, housing and health care of livestock for getting maximum benefits. Livestock refers to farm animals (domesticated animals) such as cow, sheep, etc.

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Are they safe

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Today's Dietitian magazine, the leading news source for dietitians and nutritionists, covering topics such as diabetes management, long-term care, new products and technologies, career strategies, nutrition research updates, supplements, culinary arts, food allergies, fitness, sports medicine, and much more.

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PRINTED FROM the OXFORD RESEARCH ENCYCLOPEDIA, ENVIRONMENTAL SCIENCE (environmentalscience.oxfordre.com). (c) Oxford University Press USA, 2016. All Rights Reserved. Personal use only; commercial use is strictly prohibited (for details see Privacy Policy and Legal Notice).

date: 17 April 2018

Summary and Keywords

The global area sown to genetically modified (GM) varieties of leading commercial crops (soybean, maize, canola, and cotton) has expanded over 100-fold over two decades. Thirty countries are producing GM crops and just five countries (United States, Brazil, Argentina, Canada, and India) account for almost 90% of the GM production. Only four crops account for 99% of worldwide GM crop area. Almost 100% of GM crops on the market are genetically engineered with herbicide tolerance (HT), and insect resistance (IR) traits. Approximately 70% of cultivated GM crops are HT, and GM HT crops have been credited with facilitating no-tillage and conservation tillage practices that conserve soil moisture and control soil erosion, and that also support carbon sequestration and reduced greenhouse gas emissions. Crop production and productivity increased significantly during the era of the adoption of GM crops; some of this increase can be attributed to GM technology and the yield protection traits that it has made possible even if the GM traits implemented to-date are not yield traits per se. GM crops have also been credited with helping to improve farm incomes and reduce pesticide use. Practical concerns around GM crops include the rise of insect pests and weeds that are resistant to pesticides. Other concerns around GM crops include broad seed variety access for farmers and rising seed costs as well as increased dependency on multinational seed companies. Citizens in many countries and especially in European countries are opposed to GM crops and have voiced concerns about possible impacts on human and environmental health. Nonetheless, proponents of GM crops argue that they are needed to enhance worldwide food production. The novelty of the technology and its potential to bring almost any trait into crops mean that there needs to remain dedicated diligence on the part of regulators to ensure that no GM crops are deregulated that may in fact pose risks to human health or the environment. The same will be true for the next wave of new breeding technologies, which include gene editing technologies.

Keywords: genetically modified, herbicide tolerance, insect resistance, trait

Introduction

Genetically modified organisms (GMOs) result from recombinant DNA technology that allows for DNA to be transferred from one organism to another (transgenesis) without the genetic transfer limits of species to species barriers and with successful expression of transferred genes in the receiving organism (Gray, ). Four crops, maize, canola, soybean, and cotton, constitute the vast majority of GM crop production (James, ), and GM crops have been grown commercially since 1995 (Bagavathiannan, Julier, Barre, Gulden, & Van Acker, ). The acceptance of GM crops by farmers has been rapid, with the global GM production area growing from 1.7 million hectares in 1996 (International Service for the Acquisition of Agri-biotech Applications [ISAAA], ) to 182 million hectares in 2014 (James, ). Just 10 countries represent almost 98% of the GM hectares worldwide. The top GM producing countries are the United States (73.1 million ha), Brazil (42.2 million ha), Argentina (24.3 million ha), Canada (11.6 million ha), and India (11.6 million ha) (James, ). GM soybean is the most popular GM crop and almost 50% of global soybean acres are now GM soybean (James, ). For corn and cotton the global proportion of GM is 30% and 14%, respectively (James, ). GM canola occupies only 5% of the global canola hectares (James, ). GM crops are grown on only 3.7% of the world's total agricultural land, by less than one percent of the world's farmers. Almost 100% of GM crops on the market are either herbicide tolerant (HT) or insect resistant or have both of these two traits (Dill, CaJacob, & Padgette, ).

The production of GM crops is not equal across the world and in some jurisdictions there is little or no production. Countries in the European Union (EU) are a notable example in this regard. The near complete moratorium on the production of GM crops in the EU is based on common public view and political decisions rather than GM food safety assessment (Fischer, Ekener-Petersen, Rydhmer, & Edvardsson Björnberg, ). This is also true for Switzerland, where, for example, since 2005 GM foods and crops have been banned because of strong negative views on the part of both Swiss farmers and citizens (Mann, ). Five EU countries (Spain, Portugal, the Czech Republic, Slovakia and Romania) accounted for 116,870 hectares of Bt maize cultivation in 2015, down 18% from the 143,016 hectares in 2014. The leading EU producer is Spain, with 107,749 hectares of Bt maize in 2015, down 18% from the 131,538 hectares in 2014 (James, ). Russia is the world largest GM-free zone (James, ). Despite the claimed benefits over risks, and the wide adoption of biotech-improved crop varieties in many parts of the world, Europe and Africa still remain largely GM-free in terms of production (Paarlberg, ). This may be due in part to the relative absence of reliable public scientific studies on the long-term risks of GM crops and foods and the seed monopoly that is linked to GM technology development (Paarlberg, ). In Asia, four countries, including Turkey, have banned GM crops. The GM concerns in Europe have also slowed down the approval of GM crops in many developing countries because of impacts on agricultural exports (Inghelbrecht, Dessein, & Huylenbroeck, ). Many African governments have been slow to approve, or have sometimes even banned GM crops, in order not to lose export markets and to maintain positive relations with the EU, especially given implications for development aid (Wafula, Waithaka, Komen, & Karembu, ). In addition, a few African nations have banned GM cultivation over fears of losing European markets (ISAAA, ). Public concerns over GM crops and foods have also had an impact on production of GM crops in North America. The withdrawal of the GM Bt potato (NewLeaf™) varieties from the North American market due to the concerns of two of the largest buyers of processing potatoes (Frito-Lay and McDonalds) was the result of feared consumer rejection (Kynda & Moeltner, ).

The extensive adaptation of GM crops does, however, also have some drawbacks. The occurrence of outcrossing with non-GM crops, gene flow, and the adventitious presence of GM crops on organic farms has sparked concerns among various stakeholders, including farmers who are growing GM crops (Ellstrand, ; Marvier & Van Acker, ). Public concern over GM crops is centered in three areas: human health, environmental safety, and trade impacts (Van Acker, Cici, Michael, Ryan, & Sachs, ). GM biosafety is also forcing both agriculture and food companies to appreciate GM safety in their marketing decisions (Blaine & Powell, ; Rotolo et al., ). The adoption of GM crops in a given jurisdiction is a function of public GM acceptance as well as the level of public trust of regulatory authorities (Vigani & Olper, ). Examples of these include feeding the world, consumer choice, and seed ownership (Van Acker & Cici, ). Opponents of GM crops have questioned their necessity in terms of agricultural productivity to feed the world (Gilbert, ). They point to studies that have shown that current agricultural output far exceeds global calorie needs and that distribution, access, and waste are the key limitations to feeding those who are hungry and not gross production per se (Altieri, ).

The novelty of GM technology has been both an asset and a challenge for those companies producing GM seeds. Supporters of GM crops have asserted that GM is merely an evolution of conventional breeding approaches (Herdt, ). They have insisted that humans have been genetically modifying crops for millennia and that GM technology has been an extension and facilitation of natural breeding. At the same time, however, GM crops are patentable, emphasizing that the process is truly novel and different from the natural breeding (Boucher, ). In addition, expert technical assessments acknowledge the unique and novel nature of GM crops (Taylor, ). This situation highlights the conundrum and challenge of not only introducing disruptive new technologies into society but having such technologies accepted by society (Van Acker et al., ). The socioeconomic nature of most risks along with the continuing farm income crisis in North America has led some to argue for the adoption of a more comprehensive approach to risk assessment of GM crops and all new agricultural technologies (Mauro et al., ).

The Green Revolution was driven by global hunger, and some argue that the next agricultural production revolution, which is perhaps being sparked by the introduction of GM crops, would be driven by other global needs including sustainability and the needs of individuals (Lipton & Longhurst, ). The green revolution of the 1960s and 1970s depended on the use of fertilizers, pesticides, and irrigation methods to initiate favorable conditions in which high yielding modern varieties could thrive. Between 1970 and 1990, fertilizer use in developing countries rose by 360% while pesticide use increased by 7 to 8% annually. The environmental impacts of the adoption of these technologies did in some cases override their benefits. These impacts included polluted land, water, and air, and the development of resistant strains of pests. GM crops could be used to sustain or grow production levels while diminishing environmental impacts yet despite the rapid adoption of GM crops many of the problems associated with the green revolution remain (Macnaghten & Carro-Ripalda, ). The pros and cons of GM crops are many and diverse but there is little argument over the ambiguous consequences of this comparatively new technology, and numerous critics noted the potential pros and cons of GM crops as soon as they were launched in the early 1990s (Mannion, , , ).

Pros of GMO Crop Farming

The world population has exceeded 7 billion people and is forecasted to reach beyond 11 billion by 2100 (United Nations, ). The provision of an adequate food supply for this booming population is an ongoing and tremendous challenge. The companies that develop GM seeds point to this challenge as the key rationale for their need, and they explain that GM seeds will help to meet the "feeding the world" challenge in a number of ways

Herbicide Tolerance and Pest Management

Herbicide tolerance (HT) in GM crops is achieved by the introduction of novel genes. The control of weeds by physical means or by using selective herbicides is time-consuming and expensive (Roller & Harlander, ). The most widely adopted HT crops are glyphosate tolerant (Dill, CaJabob, & Padgette, ) colloquially (and commercially for Monsanto) known as "Roundup Ready" crops. Herbicide tolerant GM crops have provided farmers with operational benefits. The main benefits associated with HT canola, for example, were easier and better weed control (Mauro & McLachlan, ). The development of GM HT canola varieties has also been linked to incremental gains in weed control and canola yield (Harker, Blackshaw, Kirkland, Derksen, & Wall, ). Despite all of the weed management options available in traditional canola, significant incentives remained for the development of HT canola. The most apparent incentives were special weed problems such as false cleavers ( Galium aparine) and stork's bill ( Erodium cicutarium), and the lack of low-cost herbicide treatments for perennials such as quackgrass ( Agropyron repens) and Canada thistle ( Cirsium arvense). Mixtures of herbicides can control many of the common annual and perennial weeds in western Canada but they are expensive and not necessarily reliable (Blackshaw & Harker, ). In addition, some tank-mixtures led to significant canola injury and yield loss (Harker, Blackshaw, & Kirkland, ). Thus, canola producers welcomed the prospect of applying a single nonselective herbicide for all weed problems with little concern for specific weed spectrums, growth stages, tank mixture interactions (i.e., antagonism or crop injury) and/or extensive consultations. Two major GM HT canola options are widely used in western Canada. Canola tolerant to glufosinate was the first transgenic crop to be registered in Canada (Oelck et al., ). Canola tolerant to glyphosate (Roundup Ready) followed shortly thereafter. The GM HT canola offers the possibility of improved weed management in canola via a broader spectrum of weed control and/or greater efficacy on specific weeds (Harker et al., ). The greatest gains in yield attributed to the adoption of GM HT crops has been for soybean in the United States and Argentina and for GM HT canola in Canada (Brookes & Barfoot, ).

The reduction of pesticide applications is a major direct benefit of GM crop cultivation: reducing farmers' exposure to chemicals (Hossain et al., ; Huang, Hu, Rozelle, & Pray, ) and lowering pesticide residues in food and feed crops, while also releasing less chemicals into the environment and potentially increasing on-farm diversity in insects and pollinators (Nickson, ). Additionally, improved pest management can reduce the level of mycotoxins in food and feed crops (Wu, ). Insect resistance in GM crops has been conferred by transferring the gene for toxin creation from the bacterium Bacillus thuringiensis (Bt) into crops like maize. This toxin is naturally occurring in Bt and is presently used as a traditional insecticide in agriculture, including certified organic agriculture, and is considered safe to use on food and feed crops (Roh, Choi, Li, Jin, & Je, ). GM crops that produce this toxin have been shown to require little or no additional pesticide application even when pest pressure is high (Bawa & Anilakumar, ). As of the end of the 21st century, insect resistant GM crops were available via three systems (Bt variants). Monsanto and Dow Agrosciences have developed SmartStax maize, which has three pest management attributes, including protection against both above-ground and below-ground insect pests, and herbicide tolerance, which facilitates weed control (Monsanto, ). SmartStax maize GM varieties were first approved for release in the United States in 2009 and combine traits that were originally intended to be used individually in GM crops (Mannion & Morse, ). Significant reductions in pesticide use is reported by adoption of Bt maize in Canada, South Africa, and Spain, as well as Bt cotton, notably in China (Pemsl, Waibel, & Gutierrez, ), India (Qiam, ), Australia, and the United States (Mannion & Morse, ).

Cons of GMO Crop Farming

The intensive cultivation of GM crops has raised a wide range of concerns with respect to food safety, environmental effects and socioeconomic issues. The major cons are explored for cross-pollination, pest resistance, human health, the environment, the economy, and productivity.

Cross-Pollination

The out crossing of GM crops to non-GM crops or related wild type species and the adventitious mixing of GM and non-GM crops has led to a variety of issues. Because of the asynchrony of the deregulation of GM crops around the world, the unintended presence of GM crops in food and feed trade channels can cause serious trade and economic issues. One example is "LibertyLink" rice, a GM variety of rice developed by Bayer Crop Science, traces of which were found in commercial food streams even before it was deregulated for production in the United States. The economic impact on U.S. rice farmers and millers when rice exports from the United States were halted amounted to hundreds of millions of dollars (Bloomberg News, ). A more recent example is Agrisure Viptera corn, which was approved for cultivation in the United States in 2009 but had not yet been deregulated in China. Exports of U.S. corn to China contained levels of Viptera corn, and China closed its borders to U.S. corn imports for a period. The National Grain and Feed Association (NGFA) had encouraged Syngenta to stop selling Viptera because of losses U.S. farmers were facing, and there is an ongoing class-action lawsuit in the United States against Syngenta (U.S. District Court, ). Concerns over the safety of GM food have played a role in decisions by Chinese officials to move away from GM production. Cross-pollination can result in difficulty in maintaining the GM-free status of organic crops and threaten markets for organic farmers (Ellstrand, Prentice, & Hancock, ; Van Acker, McLean, & Martin, ). The EU has adopted a GM and non-GM crop coexistence directive that has allowed nation-states to enact coexistence legislation that aims to mitigate economic issues related to adventitious presence of GM crops in non-GM crops (Van Acker et al., ).

Some critics of GM crops express concerns about how certain GM traits may provide substantive advantages to wild type species if the traits are successfully transferred to these wild types. This is not the case for GM HT traits, which would offer no advantage in non-cropped areas where the herbicides are not used, but could be an issue for traits such as drought tolerance (Buiatti, Christou, & Pastore, ). This situation would be detrimental because the GM crops would grow faster and reproduce more often, allowing them to become invasive (FAO, ). This has sometime been referred to as genetic pollution (Reichman et al., ). There are also some concerns that insects may develop resistance to the pesticides after ingesting GM pollen (Christou, Capell, Kohli, Gatehouse, & Gatehouse, ). The potential impact of genetic pollution of this type is unclear but could have dramatic effects on the ecosystem (Stewart et al., ).

Productivity

Justification for GM crops on the basis of the need to feed the world is often used by proponents of the technology, but the connection between GM crops and feeding the world is not direct. GM crops are used by farmers and are sold primarily on the basis of their direct operational benefits to farmers, including the facilitation of production and/or more production (Mauro et al., ). Farmers realize these benefits in terms of cost savings or increased production or both and are looking to increase their margins by using the technology. Companies producing GM seeds can be very successful if they are able to capture a greater share of a seed market because they supply farmers with operational benefits such as simplified weed management (Blackshaw & Harker, ) even if there are no productivity gains. In addition, the traits in GM crops on the market as of the early part of the 21st century are not yield traits per se but are yield potential protection traits that may or may not result in greater productivity.

Conclusions

Genetic modification via recombinant DNA technology is compelling because it does provide a means for bringing truly novel traits into crops and the adoption of GM crops has been rapid in a range of countries around the world. Only a very limited number of traits have been incorporated to date into GM crops, the two primary traits being herbicide tolerance (HT) and insect resistance. Nonetheless, farmers who have adopted GM crops have benefited from the operational benefits they provide, and current GM crops have facilitated the adoption of more sustainable farming practices, in particular, reduced tillage. The ongoing asynchronous approvals of GM crops around the world mean that there will always be issues related to the adventitious presence of GM crops in crop shipments and trade disruptions. Pollen mediated gene flow from crop to crop and seed admixtures are challenges of GM crop farming and agricultural marketing as a result. The adoption of GM HT crops has also accelerated the evolution of herbicide resistant weeds, which has created additional operational challenges and costs for farmers. The GM crops commercialized to date have all been deregulated and deemed to be safe to the environment and safe in terms of human health by competent authorities around the world, including the European Food Safety Association. There remain, however, critics of the technology who point to a lack of public research on the potential risks of GM and GM crops. GM crops will continue to be developed because they provide real operational benefits for farmers, who are the ones who purchase the seeds. The novelty of the technology and its potential to bring almost any trait into crops mean that there needs to remain dedicated diligence on the part of regulators to ensure that no GM crops are deregulated that may in fact pose risks to human health or the environment, but there will also remain the promise of the value of novel inventions that bring benefits to consumers and the environment. The same will be true for the next wave of new breeding technologies, which include gene editing technologies such as CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) (Cong et al., ). These new technologies have even greater potential for modifying crops than GM technology and they avoid some of the characteristics of GM technology that have underpinned criticisms including, for example, the presence of foreign DNA.

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Pros and Cons of GMO Crop Farming - Oxford Research Encyclopedia of Environmental Science

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The global area sown to genetically modified (GM) varieties of leading commercial crops (soybean, maize, canola, and cotton) has expanded over 100-fold over two decades. Thirty countries are producing GM crops and just five countries (United States, Brazil, Argentina, Canada, and India) account for almost 90% of the GM production.

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How does it work?

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It may seem impossible that animals as different as Great Danes and Chihuahuas could both be members of the same species. Natural selection is the process by which organisms change over generations in response to environmental pressures, but humans also selectively breed plants and animals for traits that suit their needs in a process called artificial selection. Varieties of vegetables, such as broccoli, cabbage and kale, which all originated from wild mustard, are also examples of artificial selection.

Humans favor certain traits in the plants and animals they breed for various reasons, such as high sugar content in some fruits and vegetables, speed in race horses or high milk production in dairy animals. A desirable trait might represent one end of the spectrum of variation, such as animals that are larger or smaller than their species' average, or it might be a mutation that humans wish to perpetuate. An example of the latter is seedless fruit, an especially relevant example since the sterile fruit must rely on humans to help them reproduce.

Once a desirable trait has been identified, you then select those individuals that exhibit the trait and breed them together. Over successive generations of breeding, you only select those individuals that exhibit the trait you want. If the trait exists on a continuum, selective breeding means choosing those individuals that express the trait most strongly. Depending on the underlying genetic complexity and the degree to which a trait is heritable, or influenced by genetics, selective breeding over generations creates a population with the desired trait.

The flip side of selective breeding is culling. Culling is removing individuals from the breeding population that do not have desirable traits. Depending on the type of plant or animal, culling can mean killing the individual or allowing it to live out its life, but not allowing it into the breeding population. Culling is probably the most controversial part of artificial selection in animals, since it can mean that otherwise healthy animals are killed.

The objective of artificial selection is a population that reliably produces offspring with desired traits, called a breed or varietal. Sometimes selective breeding leads to an organism so different from its wild ancestor that it becomes a whole new species. Once you have a breed or varietal, you may be able to cross-breed it with another breed to get the desirable traits of both, although cross-bred organisms are more variable. For example, you could breed a disease-resistant variety of pea with one that has high yields, which may yield offspring possessing both traits. You may also be able to cross-breed two species. Donkeys and horses produce mules, which are sterile -- they can't produce offspring -- but our modern corn is the result of breeding maize with another wild grass, teosinte.

Selective breeding, especially when you are selecting very strongly for one trait or for an extreme trait, can come with some baggage. Selective breeding tends to take genetic variability out of the population. This means that there are fewer traits competing with your desirable trait, but it can also concentrate mutations that may be problematic for the individual, such as hip dysplasia in dogs. Artificial selection in a species often must balance the desirability of a wide suite of traits with the overall health and robustness of the population.

About the Author

Based in Wenatchee, Wash., Andrea Becker specializes in biology, ecology and environmental sciences. She has written peer-reviewed articles in the "Journal of Wildlife Management," policy documents,and educational materials. She holds a Master of Science in wildlife management from Iowa State University. She was once charged by a grizzly bear while on the job.

Photo Credits

Photos.com/Photos.com/Getty Images

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Describe the Process of Artificial Selection

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It may seem impossible that animals as different as Great Danes and Chihuahuas could both be members of the same species. Natural selection is the process by which organisms change over generations in response to environmental pressures, but humans also selectively breed plants and animals for traits that suit their ...

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Is the cost worth it?

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Drugs that act by modifying a patient's genes are close to approval in the United States, and one is already available in Europe. The developments mark a triumph for the field of gene therapy, once considered controversial.

But with estimated price tags of at least US$1 million per patient, how will anyone pay for these treatments? The question is just one in a broader debate about how to finance a range of super-expensive drugs that are now available, thanks to an explosion in genetic and molecular-biology research over the past 20 years.

"Advances in science are presenting a social affordability question like never before," says economist Mark Trusheim at the Massachusetts Institute of Technology in Cambridge. "Do we want to convert the science into therapies that we actually would have to pay for?"

Trusheim spoke at the Biotechnology Innovation Organization (BIO) meeting in San Francisco, California, on 6-9 June, which featured much discussion about how society will pay for the rising costs of new drugs. At the American Society of Clinical Oncology meeting in Chicago, Illinois, on 3-7 June, dozens of talks and abstracts focused specifically on the growing cost of cancer care. Cancer drugs that unleash the power of the immune system cost up to $40,000 per month.

Gene therapies that are close to US approval include treatments for haemophilia B, sickle-cell anaemia and the neurodegenerative disease cerebral adrenoleukodystrophy. A therapy under development at Spark Therapeutics in Philadelphia, Pennsylvania, for a type of blindness is considered the most advanced.

Many of the treatments deliver corrective genes using a modified virus that is considered safer than vectors used in earlier attempts. But many of the target disorders are rare, limiting the population that can be treated. And there are often no previously approved drugs that work similarly, removing the pressure on companies to lower their prices.

Such therapies could cost $1 million per patient, estimate haematologist Stuart Orkin of Harvard Medical School in Boston, Massachusetts, and Philip Reilly, an investor with Third Rock Ventures in Boston ( S. H. Orkin and P. Reilly Science 352, 1059-1061; 2016). Reilly co-founded Cambridge-based Bluebird Bio, which is working on several of the gene therapies that are close to market.

That's the same price as Glybera, the gene therapy given the green light by European regulators in 2012, which has been taken by only one person so far. Experts attribute this low uptake to the high price and to doubts about its efficacy. If newer gene therapies are to do better, they will have to produce convincing data that they are worth the money, Trusheim says.

For medicines that are already approved, one increasingly popular solution is a deal between insurers and drug companies that ties payments to how well medicines perform. Last November, for example, Boston-based Harvard Pilgrim Health Care, a major New England insurer, announced that it will cover treatment for its clients with Repatha (evolocumab), one of a new class of cholesterol-lowering medication that is made by Amgen and costs $14,000. But if patients don't reach pre-agreed cholesterol levels, or if Harvard Pilgrim ends up paying more than it has budgeted for, Amgen will refund the insurer.

Networks set up by insurance companies to gather and share data from health centres make such deals possible, says Michael Sherman, chief medical officer at Harvard Pilgrim. And they are on the rise around the world: one study found 'pay-for-performance' deals across 14 countries in 2013, predominantly in Europe and the United States, but also in middle-income countries such as China and Brazil.

These deals may work for some conditions, such as haemophilia B, for which several drugs might be approved. But for others, such as adrenoleukodystrophy, only one company is developing a product, so there won't be the incentive for companies to negotiate, Trusheim says.

At the BIO meeting, investors and economists discussed a range of alternative solutions, including the medical equivalent of a mortgage or annuity, in which insurance companies or governments might spread the cost of a one-time treatment over many years, as long as a patient continues to benefit from it. One complication of such arrangements in the United States is that patients often move between insurers, so it is unclear who would continue to make these payments on a patient's behalf.

The difficulties of paying for the fruits of the biotechnology revolution are something that governments are already struggling with. The state of Arkansas last year settled a lawsuit filed by three people who said they had been denied access to the $300,000 cystic fibrosis drug Kalydeco (ivacaftor) because of the cost. And in April, the Japanese government imposed a 50% price cut on a new hepatitis C treatment, Sovaldi (sofosbuvir). A US federal judge in Seattle, Washington, ruled on 27 May that states cannot delay treatment with Sovaldi, which costs up to $84,000, because of price concerns.

But those working on gene therapy are confident that a solution is out there. "Let's say that a gene therapy that really made a world of difference in the life of a small child should cost a million dollars for one event," Reilly says. "I can think of many things in medicine that cost that much or more, and we don't think twice about that."

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Promising gene therapies pose million-dollar conundrum

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Drugs that act by modifying a patient's genes are close to approval in the United States, and one is already available in Europe. The developments mark a triumph for the field of gene therapy, once considered controversial. But with estimated price tags of at least US$1 million per patient, how will anyone pay for these treatments?

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Is that your right as a parent?

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Preston Gannaway

Ruthie Weiss's basketball team seemed to be minutes away from its fourth straight loss. But even as she stood on the sidelines for a brief rest, the nine-year-old had not given up. She convinced the coach to put her back in the game. Then, she charged out onto the court, caught a pass from a teammate and drove straight to the basket. Swish! Ruthie scored a quick two points, putting her team in the lead. As the game clock wound down, she scored again, clinching the victory. The team had earned its first win of the season, and celebrated as if it had just taken the national championship. A couple of parents from the opposing team even stopped by to congratulate Ruthie, who had scored all of her team's 13 points: "Wow, she's unbelievable!" they told her mum and dad.

What makes Ruthie's performance even more extraordinary is her DNA. Because of a misspelling in one of her genes, she has albinism: her body produces very little of the pigment melanin, which means that her skin and hair are fair, and that she is legally blind. Her visual acuity is ten times worse than average. She is still learning to read and will probably never be able to drive a car, but she can make out the basket and her teammates well enough to shoot, pass and play.

In January, Ruthie's dad Ethan asked her whether she wished that her parents had corrected the gene responsible for her blindness before she was born. Ruthie didn't hesitate before answering - no. Would she ever consider editing the genes of her own future children to help them to see? Again, Ruthie didn't blink - no.

The answer made Ethan Weiss, a physician-scientist at the University of California, San Francisco, think. Weiss is well aware of the rapid developments in gene-editing technologies - techniques that could, theoretically, prevent children from being born with deadly disorders or with disabilities such as Ruthie's. And he believes that if he had had the option to edit blindness out of Ruthie's genes before she was born, he and his wife would have jumped at the chance. But now he thinks that would have been a mistake: doing so might have erased some of the things that make Ruthie special - her determination, for instance. Last season, when Ruthie had been the worst player on her basketball team, she had decided on her own to improve, and unbeknownst to her parents had been practising at every opportunity. Changing her disability, he suspects, "would have made us and her different in a way that we would have regretted", he says. "That's scary."

Ethan and Ruthie are not the only people pondering these kinds of questions. The emergence of a powerful gene-editing technology, known as CRISPR-Cas9, has elicited furious debate about whether and how it might be used to modify the genomes of human embryos. The changes to their genomes would almost certainly be passed down to subsequent generations, breaching an ethical line that has typically been considered uncrossable.

But emerging technologies are already testing the margins of what people deem acceptable. Parents today have unprecedented control over what they pass on to their children: they can use prenatal genetic screening to check for conditions such as Down's syndrome, and choose whether or not to carry a fetus to term. Preimplantation genetic diagnosis allows couples undergoing in vitro fertilization to select embryos that do not have certain disease-causing mutations. Even altering the heritable genome - as might be done if CRISPR were used to edit embryos - is acceptable to some. Mitochondrial replacement therapy, which replaces a very small number of genes that a mother passes on with those from a donor, was approved last year in the United Kingdom for people who are at risk of certain genetic disorders.

Many safety, technical and legal barriers still stand in the way of editing DNA in human embryos. But some scientists and ethicists say that it is important to think through the implications of embryo editing now - before these practical hurdles are overcome. What sort of world would these procedures create for those currently living with disease and for future generations?

So far, little has been heard from the people who could be first affected by the technology - but speaking with these communities reveals a diverse set of views. Some are impatient, and say that there is a duty to use genome editing quickly to eliminate serious, potentially fatal conditions. Some doubt that society will embrace it to the degree that many have feared, or hoped. Above all, people such as Ethan Weiss caution that if policymakers do not consult people with disabilities and their families, the technology could be used unthinkingly, in ways that harm patients and society, today and in the future.

"Hearing the voices of people who live with these conditions is really important," says Tom Shakespeare, a medical sociologist at the University of East Anglia in Norwich, UK.

The cases for

John Sabine, now 60, was once described as one of the brightest legal minds of his generation in England. Now, he is in the advanced stages of Huntington's disease: he cannot walk or talk, is incontinent and requires constant care. Charles Sabine, his younger brother, carries the same genetic glitch that causes Huntington's disease, and therefore knows that, like his brother and his father before him, he is destined to undergo the same deterioration of brain and body.

Charles and his brother have five children between them, each of whom as a 50% chance of having inherited the mutation that causes Huntington's disease. To Charles - and to many others who live with the mutation that causes Huntington's - there is no legitimate ethical argument about whether gene editing should be used, either to treat people living with the condition now or to spare their children from it.

"Anyone who has to actually face the reality of one of these diseases is not going to have a remote compunction about thinking that there is any moral issue at all," Sabine says. "If there was a room somewhere where someone said, 'Look, you can go in there and have your DNA changed,' I would be there breaking the door down."

Matt Wilsey, a technology entrepreneur in San Francisco, would be there too. His daughter Grace was one of the first people in the world to be diagnosed with a disease caused by a mutation in the gene NGLY1, which makes it difficult for her cells to get rid of misshapen proteins. Grace, now six years old, has severe movement and developmental disabilities. She can barely walk and cannot talk. Because her condition is new to medicine, doctors cannot even predict how long she might live.

Wilsey is bullish on CRISPR. He says that if he had had the chance to detect and fix the mutation in Grace's genome before she was born, he would have. But he is frustrated that the debate over editing embryos seems to have monopolized discussions about the technology. He is hopeful that a gene-therapy-like approach using CRISPR, which would be free of the ethical concerns about altering the genes she passes on, could help Grace within several years. And he wonders whether a temporary moratorium on embryo editing might allow the field to focus on such approaches sooner.

"As a parent with an incredibly sick child, what are we supposed to do - sit by on the sidelines while my child dies? There's zero chance of that," Wilsey says. "CRISPR is a bullet train that has left the station - there's no stopping it, so how can we harness it for good?"

A meeting convened in December 2015 by the US national academies of sciences and medicine, the Chinese Academy of Sciences and the Royal Society of London recommended such a moratorium in light of multiple safety and ethical concerns. Still, many bioethicists and scientists have argued that if defects in single genes causing fatal and debilitating conditions could be corrected in an embryo, then they should be. Shakespeare notes that embryo editing for conditions that cause major disability and death are likely to raise less concern and criticism in the long term. But, he says: "As soon as you get away from the archetypal terrible condition, then you've got a debate about whether a condition makes life unbearably hard."

Social consequences

Many people are concerned about where that line would be drawn. Although it may seem now that only a few, very severe conditions should be subject to gene editing, disability activists point out that the list of conditions considered as illnesses, and possibly subject to medical treatment, is expanding. "More and more, people think of obesity or predisposition to alcoholism as disease," says Carol Padden, a linguist at the University of California, San Diego. She herself is deaf, and points out that many deaf people do not consider it a disability. This stance has led to controversy when, for instance, deaf parents decline technologies such as cochlear implants for their children, or even go so far as to select, through processes such as preimplantation genetic diagnosis, children who will be deaf.

Like Padden, some disability-studies researchers do not oppose the idea of gene editing, but do think that society needs to understand that it is not possible to eliminate all disability, and that humans might lose something important if they try to do so.

"These kinds of interactions significantly change our attitudes about what kinds of people matter in the world."

Padden points out that accommodations originally intended for people with disabilities often end up benefiting everyone. For example, the development of closed captioning - subtitles for the hearing-impaired on television - required major advocacy from the deaf community and legislative action to get off the ground in the United States in the 1970s. Today, people rely on it in ways that no one could have foreseen, such as in noisy airports and sports bars. Some people use it to learn to read or to learn a language.

Rosemarie Garland-Thomson, a literature scholar and co-director of the Disability Studies Initiative at Emory University in Atlanta, Georgia, adds that legislative mandates, such as the 1990 Americans with Disabilities Act in the United States, have helped to integrate people with disabilities into society - in workplaces, schools and other public spaces. As a result, the world is much more humane for everyone, says Garland-Thomson. "These kinds of interactions significantly change our attitudes about what kinds of people matter in the world."

The idea that parents should edit out characteristics that are considered debilitating goes against this drive towards inclusion, Garland-Thomson warns, and could create a harsher social climate for everyone. The experience of disability, she adds, is universal; all people inevitably experience sickness, accidents and age-related decline. "At our peril, we are right now trying to decide what ways of being in the world ought to be eliminated," she says.

Padden says that ethicists, patients and disabilities-studies researchers must work urgently to make a broad societal case in favour of greater acceptance of diversity. This has been a long-fought battle, and many see evidence of progress - for instance, in the 'neurodiversity' movement, which champions the idea that medical conditions such as autism are part of the spectrum of human variation. "We do have to start coming up with more arguments for diversity, and quickly, because CRISPR is coming upon us faster than some of us are thinking about this issue," she says.

Making choices

The prospect of editing the genome of a human embryo is still in its early stages, but the ability to prevent the inheritance of some conditions already exists. Prenatal screening, which has advanced to the point that doctors can sample a developing fetus's DNA through its mother's blood, has given parents the option to terminate pregnancies when a disease or disability is diagnosed. This has already started to show limited effects on the population.

In Europe, for example, the prevalence of a Down's syndrome diagnosis during pregnancy has risen from 20 cases per 10,000 in 1990 to 23 cases per 10,000 today, as the average age of women having babies has increased. But the number of children born with the syndrome has stayed level at about 11 per 10,000, because many women whose fetuses are diagnosed with the condition terminate their pregnancies. In the United States, pregnancies in which a Down's syndrome diagnosis is made are terminated in 67-85% of cases.

By surveying women whose fetuses and babies are diagnosed with Down's syndrome, and by compiling similar surveys from around the world, medical geneticist Brian Skotko of the Massachusetts General Hospital in Boston has found that doctors sometimes advise women to terminate or give up for adoption babies diagnosed prenatally with Down's syndrome. They can influence the decision by using phrases such as "I'm sorry", or "I have some bad news to share". For instance, 34% of 71 Dutch women who terminated their pregnancy after a Down's syndrome diagnosis said that their doctors did not even mention the possibility of carrying the pregnancy to term when discussing their options.

Mark Leach, a lawyer in Louisville, Kentucky, whose 11-year-old daughter has Down's syndrome, says that he and his wife have been asked many times - especially when his wife was pregnant with their second child - whether they "knew beforehand" that Juliet would be born with Down's. (They didn't.) Some people are simply curious, Leach says, but for others, there's judgement in that question. "The ability to do something beforehand imposes a sense of, 'You should do not only what's right for you, but what's right for society'," Leach says. It bothers him, he says, that although government and private health insurers routinely pay for prenatal diagnosis, he recently learned that his school system is discontinuing support for the learning specialist who had been helping Juliet to thrive in mathematics and reading.

Dorothy Roberts, a professor of law and sociology at the University of Pennsylvania in Philadelphia, says that this kind of pressure is troubling and that it could get worse if embryo editing were to become readily available. "Women should not be given the responsibility of ensuring the genetic fitness of their children based on lack of support for children with disabilities."

Leach knows that children with disabilities can live rich lives. Juliet likes ballet dancing and horse-riding, and she is especially attuned to the names of people and animals whom she knows. And Leach says that she helps to remind other people how to care for others. "The main thing that would be lost if Down's syndrome continues to diminish is a diminishment in the amount of compassion that is shown in this world," he says.

Even among people who already have life-threatening conditions, many choose not to interfere with the way the genetic cards are dealt. Edward Wild, a neurologist who cares for people with Huntington's disease at University College London, estimates that fewer than 5% of patients in the United Kingdom use preimplantation genetic screening to select embryos that lack the disease-causing mutation and so avoid passing it to their children. Some people do not know that they have the mutation; some decide against screening because of the costs or risks involved; some have personal or moral objections to the technique; and some just have a sense that 50-50 odds of passing down the disease are not so bad.

"Having kids the fun way is still much more popular than having kids the science way, even though the latter is how you guarantee the kid is free of Huntington's disease," Wild says.

"Prediction: my grandchildren will be embryo-screened, germline-edited. Won't 'change what it means to be human'. It'll be like vaccination."

Even if gene editing were safe, effective and everyone opted to use it, it would not eliminate genetic diseases, because researchers still have a long way to go to understand the genes involved. Even Huntington's, which is fairly well characterized, is no easy target. The glitch that causes it is a repeat of a particular genetic sequence; the more repeats, the more severe the symptoms, and repeats are added with each successive generation. New families are diagnosed with Huntington's all the time, either because the disease is misdiagnosed in older generations or because symptoms worsen, and become recognizable, in subsequent generations. Although he is working on genetic techniques to treat Huntingon's, Wild doesn't hold out high hopes for a future free of the disease. "Although it's nice to think about, it's little more than a dream," he says.

Human biology can complicate things in other ways. Padden notes, for instance, that some mutations that predispose to genetic disease, such as the sickle-cell mutation, confer population-level benefits, such as resistance to malaria. So editing out one disease could backfire by increasing the risk of another. She argues that very little is known about the potential benefits of other mutations associated with disease, and applying genome editing too freely could have unintended consequences.

And if it were adopted, the technology would almost certainly be applied unevenly around the world. Aleksa Owen, a sociologist at the University of Illinois at Chicago, predicts that genome editing would be used first in countries that approve of and support assisted reproductive technologies, such as the United Kingdom, some other European Union countries, China and Israel. But it would probably be too expensive for many people in developing countries.

Uneven access

Still, some scientists predict that editing human embryos could have transformative effects. During the National Academies' summit on gene editing in December, Harvard University geneticist Dan MacArthur tweeted, "Prediction: my grandchildren will be embryo-screened, germline-edited. Won't 'change what it means to be human'. It'll be like vaccination."

Sandy Sufian, a historian of medicine and disability at the University of Illinois, agrees with MacArthur that CRISPR has the potential to become widely adopted, both because of the perception that it would save money that would otherwise be spent caring for disabled people and because of people's fear of disability. But she questions the idea that eliminating such conditions will necessarily improve human life. Sufian has cystic fibrosis, a disease caused by mutations that render her lung cells more vulnerable to infection and disease. She spends 40 hours a week inhaling medicine to clear her lungs of mucus, exercising and undergoing physical therapy; others have to quit their jobs to make sufficient time for treatments. Yet given the option to edit cystic fibrosis out of her bloodline, Sufian wouldn't do it. "There are some great things that come from having a genetic illness," she says.

Garland-Thomson echoes that sentiment; she has one and a half arms and six fingers because of a condition called limb-reduction disorder. She says that she values traits in herself that she may have developed as adaptations to the condition: she is very sociable and wonders if that is because she's had to learn to work hard to make others feel comfortable around her. "Any kinds of restrictions or limitations have created the opportunity for me to develop work-arounds," Garland-Thomson says.

Shakespeare, who has achondroplasia, a genetic condition that causes shorter than average stature, says that people with disabilities are just as able to attain life satisfaction as others. "I have achieved everything I hoped for in life, despite having restricted growth: career, children, friendship and love." He wouldn't want to have altered his own genes to be taller, he says.

Disability rights

People without disabilities consistently underestimate the life satisfaction of those with them. Although people with disabilities report a slightly lower overall quality of life than those without, the difference is small. One study found that half of people with serious disabilities ranked their quality of life as 'good' or 'excellent'.

People also overestimate how severely health affects their happiness compared with other factors, such as economic or social support. One 1978 study, for instance, compared people who had recently become paralysed as a result of accidents with people who had recently won between US$50,000 and $1 million in a state lottery. Although people who had had accidents ranked their happiness lower than lottery winners, both groups predicted that their future happiness would be roughly equal, and people who had accidents derived more pleasure from everyday activities, such as eating breakfast or talking to a friend.

"A lot of this terrific science and technology has to take into account that the assumption of what life is like for people who are different is based on prejudice against disability," says Lennard Davis, a disability-studies researcher at the University of Illinois, who was raised by two deaf parents.

There is a common saying among people in the disability-rights community: "Nothing about us without us." People with disabilities argue that scientists, policymakers and bioethicists should take steps to ensure that the CRISPR debate reflects what is best for patients and their families, to ensure its most humane use now and for future generations.

At a minimum, they say, the investment in developing CRISPR should be matched by investments in innovations to help people who are already living with conditions that cause disability. And it is essential that people with the conditions that are up for consideration as possible CRISPR targets should be included in the decision-making processes.

For their part, Ruthie Weiss and her dad have already made up their minds. Ruthie must work harder than her classmates to do some routine activities. But when she is dominating the basketball court, or practising the piano, or skiing down a mountain, Ethan Weiss doesn't see a child with a disability. He sees his daughter making the most of her life, given all her strengths and challenges. And he knows that he wouldn't change a thing.

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Preston Gannaway Ruthie Weiss's basketball team seemed to be minutes away from its fourth straight loss. But even as she stood on the sidelines for a brief rest, the nine-year-old had not given up. She convinced the coach to put her back in the game.

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In China

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Dr. Yorgos Nikas/SPL

In a world first, Chinese scientists have reported editing the genomes of human embryos. The results are published in the online journal Protein & Cell and confirm widespread rumours that such experiments had been conducted - rumours that sparked a high-profile debatelast month about the ethical implications of such work.

In the paper, researchers led by Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou, tried to head off such concerns by using 'non-viable' embryos, which cannot result in a live birth, that were obtained from local fertility clinics. The team attempted to modify the gene responsible for β-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. The researchers say that their results reveal serious obstacles to using the method in medical applications.

"I believe this is the first report of CRISPR/Cas9 applied to human pre-implantation embryos and as such the study is a landmark, as well as a cautionary tale," says George Daley, a stem-cell biologist at Harvard Medical School in Boston, Massachusetts. "Their study should be a stern warning to any practitioner who thinks the technology is ready for testing to eradicate disease genes."

Some say that gene editing in embryos could have a bright future because it could eradicate devastating genetic diseases before a baby is born. Others say that such work crosses an ethical line: researchers warned in Nature in March that because the genetic changes to embryos, known as germline modification, are heritable, they could have an unpredictable effect on future generations. Researchers have also expressed concerns that any gene-editing research on human embryos could be a slippery slope towards unsafe or unethical uses of the technique.

The paper by Huang's team looks set to reignite the debate on human-embryo editing - and there are reports that other groups in China are also experimenting on human embryos.

Problematic gene

The technique used by Huang's team involves injecting embryos with the enzyme complex CRISPR/Cas9, which binds and splices DNA at specific locations. The complex can be programmed to target a problematic gene, which is then replaced or repaired by another molecule introduced at the same time. The system is well studied in human adult cells and in animal embryos. But there had been no published reports of its use in human embryos.

Huang and his colleagues set out to see if the procedure could replace a gene in a single-cell fertilized human embryo; in principle, all cells produced as the embryo developed would then have the repaired gene. The embryos they obtained from the fertility clinics had been created for use in in vitro fertilization but had an extra set of chromosomes, following fertilization by two sperm. This prevents the embryos from resulting in a live birth, though they do undergo the first stages of development.

Huang's group studied the ability of the CRISPR/Cas9 system to edit the gene called HBB, w hich encodes the human β-globin protein. Mutations in the gene are responsible for β-thalassaemia.

Serious obstacles

The team injected 86 embryos and then waited 48 hours, enough time for the CRISPR/Cas9 system and the molecules that replace the missing DNA to act - and for the embryos to grow to about eight cells each. Of the 71 embryos that survived, 54 were genetically tested. This revealed that just 28 were successfully spliced, and that only a fraction of those contained the replacement genetic material. "If you want to do it in normal embryos, you need to be close to 100%," Huang says. "That's why we stopped. We still think it's too immature."

His team also found a surprising number of 'off-target' mutations assumed to be introduced by the CRISPR/Cas9 complex acting on other parts of the genome. This effect is one of the main safety concerns surrounding germline gene editing because these unintended mutations could be harmful. The rates of such mutations were much higher than those observed in gene-editing studies of mouse embryos or human adult cells. And Huang notes that his team likely only detected a subset of the unintended mutations because their study looked only at a portion of the genome, known as the exome. "If we did the whole genome sequence, we would get many more," he says.

Ethical questions

Huang says that the paper was rejected by Nature and Science, in part because of ethical objections; both journals declined to comment on the claim. ( Nature 's news team is editorially independent of its research editorial team.)

He adds that critics of the paper have noted that the low efficiencies and high number of off-target mutations could be specific to the abnormal embryos used in the study. Huang acknowledges the critique, but because there are no examples of gene editing in normal embryos he says that there is no way to know if the technique operates differently in them.

Still, he maintains that the embryos allow for a more meaningful model - and one closer to a normal human embryo - than an animal model or one using adult human cells. "We wanted to show our data to the world so people know what really happened with this model, rather than just talking about what would happen without data," he says.

But Edward Lanphier, one of the scientists who sounded the warning in Nature last month, says: "It underlines what we said before: we need to pause this research and make sure we have a broad based discussion about which direction we're going here." Lanphier is president of Sangamo BioSciences in Richmond, California, which applies gene-editing techniques to adult human cells.

Huang now plans to work out how to decrease the number of off-target mutations using adult human cells or animal models. He is considering different strategies - tweaking the enzymes to guide them more precisely to the desired spot, introducing the enzymes in a different format that could help to regulate their lifespans and thus allow them to be shut down before mutations accumulate, or varying the concentrations of the introduced enzymes and repair molecules. He says that using other gene-editing techniques might also help. CRISPR/Cas9 is relatively efficient and easy to use, but another system called TALEN is known to cause fewer unintended mutations.

The debate over human embryo editing is sure to continue for some time, however. CRISPR/Cas9 is known for its ease of use and Lanphier fears that more scientists will now start to work towards improving on Huang's paper. "The ubiquitous access to and simplicity of creating CRISPRs," he says, "creates opportunities for scientists in any part of the world to do any kind of experiments they want."

A Chinese source familiar with developments in the field said that at least four groups in China are pursuing gene editing in human embryos.

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Chinese scientists genetically modify human embryos

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Dr. Yorgos Nikas/SPL In a world first, Chinese scientists have reported editing the genomes of human embryos. The results are published in the online journal Protein & Cell and confirm widespread rumours that such experiments had been conducted - rumours that sparked a high-profile debatelast month about the ethical implications of such work.

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Our experiences have told us that, with a little work, we humans can clone just about anything we want, from frogs to sheep-and probably even ourselves.

So we can clone things. But why would we want to? Below are some of the ways in which cloning might be useful.

Cloning for medical purposes has the potential to benefit large numbers of people. How might cloning be used in medicine?

Cloning animal models of disease

Much of what researchers learn about human disease comes from studying animal models such as mice. Often, animal models are genetically engineered to carry disease-causing mutations in their genes. Creating these transgenic animals is a time-intensive process that requires trial-and-error and several generations of breeding. Cloning could help reduce the time needed to make a transgenic animal model, and the result would be a population of genetically identical animals for study.

Cloning to make stem cells

Stem cells build, maintain, and repair the body throughout our lives. Because these are processes that stem cells do naturally, they can be manipulated to repair damaged or diseased organs and tissues. But stem cells transferred from one person to another (such as in a bone marrow transplant) are seen as foreign, and they usually trigger an immune response.

Some researchers are looking at cloning as a way to create stem cells that are genetically identical to an individual. These cells could then be used for medical purposes, possibly even for growing whole organs. And stem cells cloned from someone with a disease could be grown in culture and studied to help researchers understand the disease and develop treatments.

In 2013, scientists at Oregon Health and Science University were the first to use cloning techniques to successfully create human embryonic stem cells. The donor DNA came from an 8-month-old with a rare genetic disease.

Find out more about Stem Cells.

You might have seen the Jurassic Park movies. In the original feature film, based on the Michael Crichton novel, scientists use DNA preserved for tens of millions of years to clone dinosaurs. They run into trouble, however, when they realize that the cloned creatures were smarter and fiercer than expected. Could we really clone dinosaurs?

In theory? Yes. You would need:

A well-preserved source of DNA from the extinct dinosaur, and

A closely related species, currently living, that could serve as an egg donor and surrogate mother.

In reality? Probably not.

It's extremely unlikely that dinosaur DNA could survive undamaged for such a long time. However, scientists have been working to clone species that became extinct more recently, using DNA from well-preserved tissue samples. A number of projects are underway to clone extinct species, including the wooly mammoth.

In 2009, scientists had their first near-success resurrecting an extinct animal. Using goats as egg donors and surrogates, they made several clones of a wild mountain goat called the bucardo-but the longest-surviving clone died soon after birth. Even if the effort eventually succeeds, the only frozen tissue sample comes from a female, so it will only produce female clones. However, scientists speculate they may beable to remove one X chromosome and add a Y chromosome from a related goat species to make a male.

Cloning endangered species is much easier, mainly because the surviving animals can donate healthy, living cells. In fact, several wild species have been cloned already, including two relatives of cattle called the guar and the banteng, mouflon sheep, deer, bison, and coyotes. However, some experts are skeptical that cloning can help a species recover. One big challenge endangered species face is the loss of genetic diversity, and cloning does nothing to address this problem. When a species has high genetic diversity, there is a better chance that some individuals would have genetic variations that could help them survive an environmental challenge such as an infectious disease. Cloning also does not address the problems that put the species in danger in the first place, such as habitat destruction and hunting. But cloning may be one more tool that conservation scientists can add to their toolbox.

Learn more about Conservation Genetics.

Left: the alpine ibex, a close cousin of the Bucardo. Right: the last remaining Bucardo with the research team before her eventual death. She was blindfolded to shield her eyes from the photographer's flash. Image courtesy of Advanced Cell Technology.

Reproducing a Deceased Pet

If you really wanted to, and if you had enough money, you could clone your beloved family cat. At least one biotechnology company in the United States has offered cat cloning services for the privileged and bereaved. But don't assume that your cloned kitty will be exactly the same as the one you know and love. An individual is a product of more than its genes-the environment plays an important role in shaping personality and many other traits.

On December 22, 2001, a kitten named CC made history as the first cat-and the first domestic pet-ever to be cloned. CC and Rainbow, the donor of CC's genetic material, are pictured at the right.

But do you notice something odd about this picture? If CC is a clone of Rainbow-an exact genetic copy-then why are they different colors?

The answer lies in the X chromosome. In cats, a gene that helps determine coat color resides on this chromosome. Both CC and Rainbow, being females, have two X chromosomes. (Males have one X and one Y chromosome.) Since the two cats have the exact same X chromosomes, they have the same two coat color genes, one specifying black and the other specifying orange.

Very early in her development, each of Rainbow's cells "turned off" oneentire X chromosome, thereby turning off either the black or the orange color gene. This process, called X-inactivation, happens normally in females, in order to prevent them from having twice as much X-chromosome activity as males. It also happens randomly, meaning that different cells turn off different X chromosomes.

So like all female mammals, Rainbow developed as a mosaic. Each cell that underwent X-inactivation gave rise to a patch of cells that had oneor the other coat color gene inactivated. Some patches specified black,other patches specified orange, and still others specified white, due to more complex genetic events. This is how all calico cats, like Rainbow, get their markings.

CC looks different because she was made from a somatic cell from Rainbow in which the X-chromosome with the orange gene had been inactivated; only the black gene was active. What's interesting is that, as CC developed, her cells did not change the inactivation pattern. Therefore, unlike Rainbow, CC developed without any cells that specified orange coat color. The result is CC's black and white tiger-tabby coat.

Left: CC (or Carbon Copy). Right: Rainbow. Photo courtesy TAMU, College of Veterinary Medicine.

Rainbow and CC are living proof that a clone will not look exactly like the donor of its genetic material.

Programs are underway to clone agricultural animals, such as cattle and pigs, that are efficient producers of high-quality milk or meat.

A group of researchers at Utah State University led by Dr. Ken White, Dean of College of Agriculture & Applied Science, have been able to clone steer from slaughterhouse carcasses. Their aim isn't to produce animals for consumption-cloning is far more labor-intensive and expensive than conventional breeding methods. Instead, they want to use these animals as breeding stock.

The important thing to know about beef cattle is that the quality and yield of their meat can be assessed only after they are slaughtered. And male animals are routinely neutered when they're a few days old. That is, their testes are removed, so they are unable to make sperm. But cells from a high-quality carcass can be cloned, giving rise to an animal that is able, though conventional breeding methods, to pass its superior genes to its offspring.

Scientists have also cloned mules, a reproductively sterile hybrid of a male donkey and a female horse; dairy cows; and horses. One gelded racing horse, a male whose testes have been removed, has a clone that is available for breeding. Some of the cloned cows produce about twice as much milk as the average producer. And a cloned racing mule is ranked among the best in the world.

Farm animals such as cows, sheep, and goats are being genetically engineered to produce drugs or proteins that are useful in medicine. As an example, scientists could take cells from a cow that produces large amounts of milk and grow them in culture. Then they could insert a gene into the DNA of these cells that codes for a drug or a vaccine. If they take the nucleus from one of these cells and transfer it to a cow egg, it could develop into a cow that makes the drug in its milk. Since every cell in the cow would carry the drug gene, it could pass the gene to its offspring, creating a whole herd of drug-producing cows. Even better, we could avoid the issue of the genetic reshuffling that happensduring sexual reproduction and simply clone our drug-producing cow.

The prospect of cloning humans is highly controversial, and it raises a number of ethical, legal, and social challenges that need to be considered.

The vast majority of scientists and lawmakers view human reproductive cloning-cloning for the purpose of making a human baby-immoral. Supporters see it as a possible solution to infertility problems. Some even imagine making clones of geniuses, whose work could advance society. Far-fetched views describe farms filled with clones whose organs are harvested for transplantation-a truly horrific idea.

For now, risks and technical challenges-as well as laws that make it illegal-will probably keep human reproductive cloning from becoming a reality. Even though many species have been cloned successfully, the process is still technically difficult and inefficient. The success rate in cloning is quite low: most embryos fail to develop, and many pregnancies end in miscarriage.

Current efforts at human cloning are focused on creating embryonic stem cells for research and medicine, as described above. However, many feel that this type of therapeutic cloning comes dangerously close to human reproductive cloning. And once techniques become more streamlined and efficient, they fear that some may be tempted to take that next step.

From a technical and moral standpoint, before human cloning becomes routine, we need to have a good idea of the risks involved.

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Our experiences have told us that, with a little work, we humans can clone just about anything we want, from frogs to sheep-and probably even ourselves. So we can clone things. But why would we want to? Below are some of the ways in which cloning might be useful.

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I've decided I want to cover some recent research on social cognition in domesticated dogs. But first, we need some background. So here's a repost from the old blog.
Today I want to tell you about one of my most favorite studies, ever, of animals. Are you ready? It's a FIFTY YEAR LONG longitudinal study of captive silver foxes in Russia. Gather around, pour yourself a cup of your favorite beverage, get comfortable, and enjoy storytime.

In 1948, Soviet scientist Dmitri Belyaev lost his job at the Department of Fur Animal Breeding at the Central Research Laboratory of Fur Breeding in Moscow because of his commitment to classical genetics. At the time, in Soviet Russia, Lysenkoism was all the rage (and by that, I mean, it was state doctrine). Lysenkoism (named for its champion Trofim Lysenko) is akin to Lamarckian inheritance - than acquired characteristics could be passed down to offspring. We now know, of course, that Lamarck was basically wrong and an organism's experiences can not be genetically passed to its offspring (though there may be other mechanisms).

Our hero Belyaev was kicked out of the Fur Breeding Lab in Moscow, but he continued to study genetics under the guise of studying animal physiology throughout the 1950s. Then, in 1959, he became the director of the Institute of Cytology and Genetics of the Russian Academy of Sciences, in Novosibirsk, Russia. He remained director through 1985.

At the time, biologists were puzzled as to how dogs evolved to have different coats than wolves, since they couldn't figure out how the dogs could have inherited those genes from their ancestors. Belyaev saw silver foxes as a perfect opportunity to find out how this happened.

Belyaev believed that the key factor that was selected for was not morphological (physical attributes), but was behavioral. More specifically, he believed that tameness was the critical factor. How amenable was an animal to interacting with humans? This would certainly impact how well an animal would adapt to life with humans.
Figure 1: Dmitry Belyaev with some of his domesticated silver foxes, in 1984.
He hypothesized that selecting for tameness and against aggression would result in hormonal and neurochemical changes, since behavior was ultimately rooted in biology. It could be that the genetic differences that led to the morphological changes that biologists noticed in domesticated dogs (particularly, they noticed differences in fur coloration, and increased skull size relative to body size) were related to the genetic changes that underlied the behavioral temperament that they selected for (tameness and low aggression). He believed that he could investigate some of the questions about domestication by attempting to domesticate wild foxes. Belyaev and his colleagues took wild silver foxes (a variant of the red fox) and bred them, with a strong selection for inherent tameness.
Figure 2: Domesticated Russian silver fox
Starting at one month of age, and continuing every month throughout infancy, the foxes were tested for their reactions to an experimenter. Essentially, they were tested for their friendliness. The experimenter would attempt to pet and handle the fox while offering it food. In addition, the experimenters observed whether the foxes preferred to hang out with other foxes, or with humans.

Then, when they reached sexual maturity (7-8 months), they had their final test and assigned an overall tameness score. First, they rated each fox's tendency to approach an experimenter standing at the front of its home pen. They also rated each fox's tendency to bite the experimenters when they tried to touch it. Only those foxes who were least fearful and least aggressive were chosen for breeding. This made for two original groups of foxes: an experimental group, bred for tameness, and a control group. This has been done for over FORTY generations of such foxes. In each successive generation of the experimental group, less than 20% has been allowed to breed each year. (Later, he also bred a line of foxes to be fearful and aggressive, in a similar manner). To ensure that tameness results from genetic selection and not simply from experience with humans, the foxes are not trained and are only allowed short "time dosage" contact with their caretakers and experimenters.
Videos 1 and 2: Characteristic aggressive response in these foxes (top), and characteristic tame foxes (bottom). If the tame fox doesn't remind you of your pet dog, I don't know what will. (Source)
These experimental foxes, which were bred on a single selection criteria, displayed behavioral, physiological, and morphological (i.e. physical) characteristics that were not found in the control foxes, or in some cases, such characteristics were displayed with far higher frequency in the experimental group.

Behavioral changes: The experimental foxes were more eager to hang out with humans, whimpered to attract attention, and sniffed and licked their caretakers. They wagged their tails when they were happy or excited. Does that sound like your pet dog at all? Further, they had reduced fear responses to novel items or situations, and had enhanced exploratory behavior in unfamiliar situations.

Morphological changes: These changes were perhaps the most surprising (and gave the best support to Belyaev's predictions). A much higher proportion of experimental foxes had floppy ears, short or curly tails, extended reproductive seasons, changes in fur coloration, and changes in the shape of their skulls, jaws, and teeth. They also lost their "musky fox smell."

Physiological changes: The first change detected was in the piuitary-adrenal axis. This system is responsible for the control of adrenaline, among other things. Adrenaline is one hormone that is produced in response to stress, and controls fear-related responses. The experimental foxes had significantly lower adrenaline levels than their control-group cousins. The researchers hypothesized that foxes that are not afraid of humans are going to produce less adrenaline around them. This explains the foxes' tameness, but it doesn't account for their changed fur coloration patterns. The scientists theorized that adrenaline shares a biochemical pathway with melanin, which controls pigment production in fur.

And so it was that selecting for a single behavioral characteristic - tameness (or, put another way, selecting against fear and aggression) - resulted in changes not only in behavior, but also in correlated and unselected physical and physiological changes.

These results have led to speculation that similar models could account for the superior behavioral and cognitive traits (and physical and physiological differences) of domestic dogs over their wolf ancestors.
Belyaev, DK (1969). Domestication of animals. Science, 5 (1), 47-52. Trut, L. (1999). Early Canid Domestication: The Farm-Fox Experiment American Scientist, 87 (2) DOI: 10.1511/1999.2.160 Trut, L. (2001). Experimental Studies of Early Canid Domestication. In The Genetics of the Dog, A Ruvinsky and J. Sampson, eds. Want to read more? See the study's main website. Also, see Bora's post on these foxes and developmental timing.

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I've decided I want to cover some recent research on social cognition in domesticated dogs. But first, we need some background. So here's a repost from the old blog. Today I want to tell you about one of my most favorite studies, ever, of animals. Are you ready?

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Scientists are considering drastic measures to save the giant panda from extinction.

The same experts who cloned Dolly the sheep almost twenty years ago have taken tissue samples from Tian Tian and Yang Guang at Edinburgh Zoo

These samples were then used the tissue to create more cells, the first step in making genetic copies of the animals.

The cloning plans comes after years of failed attempts to get Tian Tian and Yang Guang to mate. Earlier this year, Tian Tian was artificially inseminated but lost the baby.

The plan is not without detractors. Conservation groups point out that cloned animals can suffer major health problems - Dolly the sheep was euthanised at six-years-old due to health problems.

Dr Bill Ritchie, who is involved in the project, told the Mail Online, "the fact that you can grow cells is a step on the way."

"This may be a source for a cloning project. People are wary about cloning and would rather go with conventional methods, but pandas are an anomaly because of their lifestyle. This is a step in bringing back an endangered species or helping preserve them."

There are currently only around 2,000 giant pandas left in the wild, living in the mountain ranges of central China. Farming and deforestation have driven the panda out of the lower land areas it used to inhabit.

Explore more about this endangered species here.

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Scientists are considering drastic measures to save the giant panda from extinction. The same experts who cloned Dolly the sheep almost twenty years ago have taken tissue samples from Tian Tian and Yang Guang at Edinburgh Zoo These samples were then used the tissue to create more cells, the first step in making genetic copies of the animals.

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To increase food sources

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It is imperative that we improve the new genotypes for sustainable plant and livestock production given the changes in demand and the environment. Until recently mutations and classical breeding techniques were sufficient to breed new varieties. At the end of the 20th century, tissue culture, gene transfer and other molecular biologic developments have entered the picture. In the past decade, a variation on mutation, which is not a new technique, has emerged. We now see thousands of new plant varieties that have been bread using artificial mutation with X or gamma rays or colchicine application. Mutation is a spontaneous or purposeful changes in one of the genes of a living organism.

Since 2010, genomic arrangements have been carried out in molecular laboratories. These genotypes, will rapidly be registered and delivered to the producers. These genomic arrangements, (also called New Plant Breeding Techniques (NPBT)), GEN EDITING, GENOM EDITING) cover a range of new gene engineering methods. Those are "Tilling, Protoplast Fusion, Cisgenesis, Oligonucleotide Techniques, CRISPR-Cas9, Zen, Talen, Epigenetics etc. with "CRISPR-Cas9" being prominent than the rest. In these methods, there is no transfer of any gene from outside like there is in GMOs. On the contrary, new genotypes are created by silencing the target gene with the help of transient DNA-cutting enzymes. This application can increase or decrease the effect of gene. We can call this process artificial micro-mutation. Naturally, these methods can be applied to plants with mapped genes.

What interesting are these methods do not require hundreds of millions of dollars for registration as is the case with GMO, which requires a lot of expenses for environment, risk etc. analyzes. Therefore, any gen edited variety can reach the seed marked in faster than any other plant breeding technique. Additionally the cost of these techniques is only one-tenth of GMO processes resulting in easy variety development by small and medium-sized or low budget new enterprise plant breeding companies, universities and public institutions. In the USA, GENOM EDITING is regulated as a conventional plant breeding system and not as a GMO registration system. Of the 23 candidate varieties of the more recent registration applications, only three of them belonged to large, global seed companies. Twenty of them emerged from 5-6 year old, small-to-mid sized enterprises or new entrepreneurs. Improving new genotypes will not be in hands of multinational companies exclusively but small enterprises will also take part in plant breeding activities which is crucial for food security in light of climate change.

Application of these new plant breeding techniques has been banned in in Europe . It raises concern that such a ban has occurred at a time when, where global warming, heat, drought and diseases, are seriously threatening the world's food safety and when nations are in desperate need of resistance or tolerant new cultivars to heat, drought and diseases. With the July 2018 decision of the European Court of Justice (ECJ), genome editing will be regulated like GMOs, and the cost of registration of any new variety will be as high as GMO's (around 150 million US$). In this case, small and medium-sized or low budget and younger plant breeding companies or universities will not be able to enter into plant breeding business. So, according to EU law, on one hand, 'conventional' mutagenesis using ionizing radiation or DNA-damaging chemicals which generate thousands of mutant varieties are safe; but on the other, one laboratory change of genome is causing regulatory alarm. Upon these developments some experts have voiced their views including:
 "This decision will have a profound effect on the academic research community in the EU";
 "Europe is breaking away from the largest biology revolution of the last 30 years;
 "Europe will be far behind in the next decade about innovations in food and agriculture;
 "It is expected that modern plant biotechnology laboratories will be closed in Europe;
 "These restrictions in biotechnology means "migration of scientists"";
 "With this decision, the EU will begin to decline for the latest technology and innovation".

The scientific community's concern is that research support will also be cut off. The fact that NPBT won't be included in the "Horizon" type framework projects, which bring together the science bodies and the implementing firms, will be a barrier for EU firms in the tomorrow's seed market.
However, Japan's Ministry of Environment is approaching this issue very differently. At an experts meeting on August 20, 2018, Japan has decided: "unless the product contains nucleic acid of other species or variety, registration procedures do not fall into the category of GMOs". And on August 29, 2018, it was accepted by the Advisory Panel on Genetically Modified Organisms as it came from the group of experts .

Let's take a look at the economic contributions of the varieties developed by classical mutation breeding without mentioning the varieties developed with NPBT. With this method, which was introduced in the middle of the 20th century, 3275 new varieties have been presented to the world producers to date. New mutant varieties were used as parents in the development of a large number of varieties. For example, in Italy, new genotypes driven from mutant Capelli durum wheat were planted in half of the whole Italian durum wheat fields in the 1970s. China is using mutation breeding more effectively. 30% of the registered 3275 new world mutant varieties belong to China. This country also uses space for conventional mutation. A total of 230 mutant varieties have been registered via space breeding research center's mutation projects in the last 30 years.

Here are a few examples of candidate cultivar lists developed with NPBT:
- Seedless tomatoes in Japan;
- Low fatty acid soy in the US (in market in 2019);
- Easier digestible alfalfa in the US;
- Herbicide resistant rice in Canada;
- Herbicide resistant flax in Canada;
- A dozen more gene-edited crops in the pipeline for as US Company, Calyxt, including high-fiber wheat and potatoes that stay fresh longer, better-tasting tomatoes, low-gluten wheat, apples that don't turn brown, drought-resistant soybeans or potatoes better suited for cold storage.

Those will not only be beneficial to plant breeders and consumers, but will also be pioneers for further crop development. In fact, we should see new cultivars for many additional species for food security in the future, given global warming.

Nazimi Acikgoz
Note: This artical is a summary of a Turkish paper published in "https://nazimiacikgoz.wordpress.com/2018/09/10/dunyada-yeni-islah-teknikleri-meyvelerini-vermege-basladi-2/" and
"http://blog.milliyet.com.tr/dunyada-yeni-islah-teknikleri-meyvelerini-vermege-basladi/Blog/?BlogNo=594118"

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New Plant Breeding Technics Have Started to Bear Fruit

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It is imperative that we improve the new genotypes for sustainable plant and livestock production given the changes in demand and the environment. Until recently mutations and classical breeding techniques were sufficient to breed new varieties. At the end of the 20th century, tissue culture, gene transfer and other molecular biologic developments have entered the picture.

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Time has been called on the northern white rhinoceros, but this call is already being challenged. When the last male on March 30, 2018, at the Ol Pejeta Conservancy in Kenya, the species was declared functionally extinct. Although the deceased rhino's daughter and granddaughter remain alive, the species is no longer reproductively viable.

However, researchers at the San Diego Frozen Zoo believe they have the means to make this a brief extinction. The zoo's archives include a large amount of cryopreserved northern white rhino genetic material. Because both of the northern females are infertile, the path to recovery runs through that of the southern white rhinoceros.

Whereas northern rhinos are facing extinction, its southern neighbor is doing exceptionally well. Approximately roam in mostly South Africa, making it by far the most populous species of rhinoceros in the world. The northern and southern relatives are believed to have from a common ancestor about 80,000 years ago as their habitats came to differ. However, genome sequencing and the successful artificial insemination of a southern white rhino by a northerner suggest that they are actually subspecies of a mutual species.

If hybridization is possible, then it is likely that cloning via nuclear transfer is as well. An unfertilized egg from a living southern white rhino could have its DNA removed and replaced with the nucleus of its northern neighbor. This is the same technique used in iconic clones like the sheep.

The methodology is more or less unquestioned and the team is proceeding apace. However, the project has been met with criticism inside and outside the scientific community. Though the genetic variation between northern and southern white rhinos is much lesser than that between true species, it is not immaterial. As such, the likelihood of harmful mutations in utero is probably elevated.

However, the biggest questions arise if the cloning is successful. The last wild member of the species was spotted in 2009; the species has since then survived fully in captivity. Both environmental degradation and poaching for horns led to the demise of the northern white rhinoceros. Habitat damage is arguably worsening, as is poaching: As rhino numbers decline, the value of the remaining horns increases through simple supply and demand. That leads critics to ask if it make sense to invest considerable resources to resurrect a species that will probably have to live entirely in captivity for the foreseeable future?

Jason Gilchrist, an ecologist at Edinburgh Napier University, believes it is unwise to revive a species that's unable to return to its ancestral environments. "What I want is to see wild ecosystems functioning as close to naturally as they can," he told . He is worried that resurrected animals would "simply be living museum exhibits, destined to live out their lives in zoos, with habitat loss or poaching preventing life in the wild."

Furthermore, the capital invested in these projects does not come out of a vacuum. The millions of dollars spent on de-extinction projects could go far in conserving other species whose situations are precarious. Three other species of rhino fit that bill. The Sumatran, Javan and black rhinos are all critically endangered, and many of those engaged in preserving them grumble about the money and attention being spent on a species they view as a lost cause.

In fact, a published in Nature determined that spending limited resources on resurrection efforts could actually lead to a net loss in biodiversity. After the species was revived, it is likely that management of the newly extant species would fall to the government, as is largely the case with endangered animals. Given the inherent difficulty of managing a species that was unable to survive in the wild, this would almost certainly be a greater public cost than that of maintaining other endangered species. However, if private funds could be raised to pay for both the resurrection and the maintenance of the formerly extinct species, then it is possible that de-extinction could occur without reducing net biodiversity.

Such is the goal of a handful of startups, which plan to use nuclear transfer to bring back a gamut of extinct species. Most prominent among them is the Sausalito-based Revive and Restore, which aims to resurrect iconic species like the passenger pigeon. For co-founders Ryan Phelan and Stewart Brand, increasing biodiversity is the explicit goal of their organization. For example, the passenger pigeon was a keystone species in the hardwood forests of the eastern United States and Canada, and much of those areas have struggled since its demise. Furthermore, a bird like the passenger pigeon would almost certainly require a fraction of the resources that the northern white rhino would to re-introduce it into the wild.

However, the team stretches the biodiversity argument thinly when justifying some of its other projects, like reviving the wooly mammoth. They note that much of what used to be vast grasslands turned to tundra and taiga after the mammoth's disappearance. And those areas are more vulnerable to the effects of climate change than are grasslands. While this is true, these environments have adapted in multifaceted ways in the thousands of years since the woolly mammoth's extinction, and it is unlikely that the re-introduction of a few woolly mammoths would be able to reverse these long-ingrained changes.

Though proponents of resurrection technology will always claim biodiversity as their motivation, it appears that much of the motivation centers around human emotions. Conservationist researcher Joseph Bennett of Carleton University believes that inspiration would be one of the primary benefits of bringing back the northern white rhino, that it could be "a really nice 'good news story' for people." Another common viewpoint is that reviving species that went extinct because of humans will grant us a form of atonement for our sins. There do seem to be a handful of cases, like the passenger pigeon, where the habitats would truly benefit from the revival of a species it used to depend on. However, humanity will not get moral redemption if it allows salvageable species to lapse into extinction due to an increasing focus on resurrecting a few charismatic, but costly, extinct species.
Sean Hall is a writer and engineering student at Santa Rosa Junior College exploring the overlap between politics and synthetic biology. Follow him on Twitter at @seantheserene.

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Resurrecting the northern white rhino and other lost species. But at what cost?

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Time has been called on the northern white rhinoceros, but this call is already being challenged. When the last male on March 30, 2018, at the Ol Pejeta Conservancy in Kenya, the species was declared functionally extinct. Although the deceased rhino's daughter and granddaughter remain alive, the species is no longer reproductively viable.

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FDA primer

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The responses to the questions provided in this document represent the FDA's view in light of the conclusions and recommendations outlined in the Animal Cloning Risk Assessment, Risk Management Plan, and Guidance for Industry #179. What is cloning, really?
What can go wrong with cloning?
Why is there interest in cloning?
Is it safe to eat food from clones?
What's next?
What is the National Academy of Sciences?
Imagine the perfect dairy cow. For eight years she has gotten pregnant on the first try, given birth easily, and produced gallon upon gallon of the best milk. Even when others in the herd got sick, she stayed healthy. She is ideally suited to the climate in which she lives. The farmer has depended on this cow and her daughters in lean times to carry the farm through, but now she is at the end of her reproductive life.

Although the farmer may have this cow's daughters to carry on the line, he also has another alternative: copying her. Biological copying is referred to as cloning. By cloning his prize cow, breeding the clones, and keeping their offspring, the farmer can introduce the natural positive characteristics into the herd quickly. It would take several more years to achieve these same improvements by conventional breeding.
Back to the top
Farmers can also clone animals to produce more uniform quality meat. Take, for example, a male swine (boar) that time after time sires offspring that mature quickly and provide lean meat. If a farmer has several of these boars he could quickly produce an entire herd with consistent, high quality meat.

Researchers have been cloning livestock since 1996. When it became apparent that cloning could become a commercial venture in 2001, the Food and Drug Administration's Center for Veterinary Medicine asked that food from clones and their offspring be voluntarily kept out of the food chain. FDA then began an intensive evaluation that included examining the safety of food from these animals.

What is cloning, really?

Cloning is a complex process that lets one exactly copy the genetic, or inherited, traits of an animal (the donor). Livestock species that scientists have successfully cloned are cattle, swine, sheep, and goats. Scientists have also cloned mice, rats, rabbits, cats, mules, horses and one dog. Chickens and other poultry have not been cloned.
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Most people think of livestock breeding taking place through traditional mating, in which males and females physically get together to reproduce. In fact, this is not often the case. Traditional mating is not that efficient, if the goal is to produce as many offspring as possible. For example, a male has enough sperm to produce many more offspring than would be possible by traditional mating. Traditional mating also has certain risks: one or both of the animals may be injured in the process of mating. The female may be hurt by the male because he is often much larger, or an unwilling female may injure the male. There is also a risk of infection or transmission of venereal disease during traditional mating.

Because of these factors, many farmers use assisted reproductive technologies (ARTs) for breeding. These include artificial insemination, embryo transfer, and in vitro fertilization (a process by which egg and sperm are united outside the body). Artificial insemination was first documented in the breeding of horses in the 14th century. The first successful embryo transfer of a cow was in 1951, and the first in vitro fertilization (IVF)-derived animal was a rabbit born in 1959. Livestock production in the United States now uses all these methods regularly. For example, most dairy farms don't have bulls, so more than 70 percent of the Holstein cows bred in the United States are artificially inseminated. The frozen semen can come from a bull many miles, or even many states, away.

Cloning is a more advanced form of these assisted reproductive technologies. Much of the public perception of cloning likely comes from science fiction books and movies. Some people incorrectly believe that clones spring forth fully formed, or are grown in test tubes. This is just not the case.

Clones are born just like other animals. They are similar to identical twins, only born at different times. Just as twins share the same DNA, clones have the same genes as the donor animal. A clone is not a mutant, nor is it a weaker version of the original animal.

In all of the other assisted reproductive technologies, the male and female parents each contribute half of their genes to their offspring. Farmers have worked for years to choose animals with the best traits and breed them together. This increases the chance these good traits will be passed on and become more common in livestock herds. Even though farmers have been able to improve their herds over time, they still can't absolutely predict the characteristics of the offspring, not even their gender. Cloning gives the farmer complete control over the offspring's inherited traits. Thus, a farmer who clones an especially desirable but aging or injured animal knows in advance that the clone will have the genetic potential to be an especially good, younger animal. He can then use that animal to further reproduce by traditional mating or other ARTs

Most cloning today uses a process called somatic cell nuclear transfer (SCNT). Just as with in vitro fertilization, scientists take an immature egg, or oocytes, from a female animal (often from ovaries obtained at the slaughterhouse). But instead of combining it with sperm, they remove the nucleus (which contains the oocytes's genes). This leaves behind the other components necessary for the initial stages of embryo development. Scientists then add the nucleus or cell from the donor animal that has the desirable traits the farmer wishes to copy. After a few other steps, the donor nucleus fuses with the ooplast (the oocytes whose nucleus has been removed), and if all goes well, starts dividing, and an embryo begins to form. The embryo is then implanted in the uterus of a surrogate dam (again the same as with in vitro fertilization), which carries it to term. ("Dam" is a term that livestock breeders use to refer to the female parent of an animal). The clone is delivered just like any other baby animal.

What can go wrong with cloning?

There are no complications that are unique to cloning. The problems seen in clones are also seen in animals born from natural mating or ARTs. They seem to happen more often in clones for a number of reasons that probably have to do with parts of the procedure that occur outside the body. The embryo may fail to develop properly during the in vitro stage or early on after transfer to the surrogate and may be flushed out of the uterus. If it does develop, the embryo may not implant properly into the uterus of the surrogate dam. Alternatively, the placenta may not form properly, and the developing animal won't get the nourishment it needs.

Large Offspring Syndrome (LOS) is seen in pregnancies of cattle and sheep that come from other ARTs and cloning. With LOS, the fetus grows too large in the uterus, making problems for the animal and its surrogate dam. LOS has not been observed in goats and swine.
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Most clones that are normal at birth become as strong and healthy as any other young animals. Calf and lamb clones tend to have more health problems at birth, and may be more likely to die right after birth than conventionally bred animals. Clones born with abnormalities may continue to have health problems for the first few months of life, but by the time clones are young adults, it's not possible to tell them apart from other animals of the same age, even if you conduct a detailed examination. Scientists at FDA and research institutions have looked at extensive health records, the development of clones, and blood work for clones that's similar to what people get when they have physicals. These results show that the clones are perfectly healthy, and walk, wean, grow, mature, and behave just like conventionally bred animals.

Why is there interest in cloning?

The main use of agricultural clones is to produce breeding stock, not food. Clones allow farmers to upgrade the overall quality of their herds by providing more copies of the best animals in the herd. These animals are then used for conventional breeding, and the sexually reproduced offspring become the food producing animals. These animals are not clones-they're just like other sexually reproduced animals. Just as farmers wouldn't use their best conventionally bred breeding animals as sources of food, they are equally unlikely to do so for clones.

Some examples of desirable characteristics in livestock that breeders might want in their herds include the following:

Disease resistance: Sick animals are expensive for farmers. Veterinary bills add up, and unhealthy animals don't produce as much meat or milk. A herd that is resistant to disease is extremely valuable because it doesn't lose any production time to illness, and doesn't cost the farmer extra money for veterinary treatment.

Suitability to Climate: Different types of livestock grow well in different climates. Some of this is natural and some results from selective breeding. For instance, Brahma cattle can cope with the heat and humidity of weather in the southwestern United States, but they often do not produce very high grades of meat. Cloning could allow breeders to select those cattle that can produce high quality meat or milk and thrive in extreme climates and use them to breed more cattle to be used for food production. Similarly, pork production has traditionally been centered in the eastern United States, but is moving to different regions of the United States (e.g., Utah). Cloning could allow breeders to select those swine that naturally do well in the new climate, and use those swine clones to breed more swine to be used for food production.

Quality body type: Farmers naturally want an animal whose body is well suited to its production function. For example, a dairy cow should have a large, well-attached udder so that she can produce lots of milk. She should also be able to carry and deliver calves easily. For animals that produce meat, farmers breed for strong, heavily-muscled, quick-maturing animals that will yield high quality meat in the shortest time possible. The most desirable bulls produce offspring that are relatively small at birth (so that they are easier for the female to carry and deliver) but that grow rapidly and are healthy after birth.

Fertility: Quality dairy cows should be very fertile, as a cow that doesn't get pregnant and bear calves won't produce milk. Male fertility is just as important as that of the female. The more sperm he can produce, the more females a bull can inseminate, and the more animals can be born. Beef cattle or other meat-producing animals such as swine need to have high fertility rates in order to replace animals that are sent to slaughter. Cloning allows farmers and breeders to clone those animals with high fertility rates so that they could bear offspring that would also tend to be very fertile.
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Market preference: Farmers or ranchers may also want to breed livestock to meet the changing tastes of consumers. These include traits like leanness, tenderness, color, size of various cuts, etc. Preferences also vary by culture, and cloning may help tailor products to the preferences of various international markets and ethnic groups.

How does cloning help get these characteristics into the herd more quickly? As we've previously said, cloning allows the breeder to increase the number of breeding animals available to make the actual food production animals. So, if a producer wanted to introduce disease resistance into a herd rapidly, cloning could be used to produce a number of breeding animals that carry the gene for disease resistance, rather than just one. Likewise, if a breeder wants to pass on the genes of a female animal, cloning could result in multiples of that female to breed, rather than just one.
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Is it Safe to Eat Food from Clones?

Yes. Food from cattle, swine, and goat clones is as safe to eat as food from any other cattle, swine, or goat. But it's important to remember that the primary purpose of clones is for breeding, not eating. Dairy, beef, or pork clones make up only a tiny fraction of the total number of food producing animals in the United States. Instead, their offspring would be the animals actually producing meat or milk for the food supply.
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Dairy clones will produce milk after they give birth, and the dairy farmers will want to be able to drink that milk or put it in the food supply. Once clones used for breeding meat-producing animals can no longer reproduce, their breeders may also want to be able to put them into the food supply.

In order to determine whether there would be any risk involved in eating meat or milk from clones or their offspring, in 1999 the FDA asked the National Academy of Sciences (NAS) to identify science-based concerns associated with animal biotechnology, including cloning. The NAS gathered an independent group of top, peer-selected scientists from across the country to conduct this study. The scientists delivered their report in the fall of 2002. That report stated that theoretically there were no concerns for the safety of meat or milk from clones. On the other hand, the report expressed a low level of concern due to a lack of information on the clones at that time, and not for any specific scientific reasons. The report also stated that the meat and milk from the offspring of clones posed no unique food safety concerns.

Meanwhile, FDA itself began the most comprehensive examination of the health of livestock clones that has been conducted. The evaluation has taken over five years. This examination formed the basis of a Draft Risk Assessment to determine whether cloning posed a risk to animal health or to humans eating food from clones or their offspring. FDA conducted a thorough search of the scientific literature on clones, and identified hundreds of peer-reviewed scientific journal articles, which it then reviewed. The agency was also able to obtain health records and blood samples from almost all of the cattle clones that have been produced in the United States and data from clones produced in other countries. FDA compared these health records, and the independently analyzed blood results with similar samples from conventional animals of the same age and breed that were raised on the same farms. FDA received thousands of comments from the public in response to the Draft Risk Assessment. For the final version of the Risk Assessment, FDA conducted an up-to-date review of the literature, added additional information from hundreds of additional references, and made many changes to address some of the public comments.

After reviewing all this information, FDA found that it could not distinguish a healthy clone from a healthy conventionally bred animal. All of the blood values, overall health records, and behaviors were in the same range for clones and conventional animals of the same breed raised on the same farms. FDA also observed that milk from dairy clones does not differ significantly in composition from milk from conventionally bred animals.

In the Risk Assessment, FDA concluded that meat and milk from cattle, swine, and goat clones is as safe as food we eat from those species now. Although we don't have any particular concerns about sheep clones, we did not have enough information to make a decision on the safety of food from sheep clones.

For another study similar to the one conducted on cow clones, the agency also evaluated the health of offspring sexually derived from swine clones, as well as the composition of their meat. After reviewing this very large data set, the agency concluded that all of the blood values, overall health records, and meat composition profiles of the progeny of clones were in the same range as for very closely genetically related conventionally bred swine. Based on these results, other studies from scientific journals, and our understanding of the biological processes involved in cloning, the agency agreed with NAS that food from the sexually reproduced offspring of clones is as safe as food that we eat every day. We reiterate, however, that the sexually reproduced offspring of clones would produce almost all of the food from the overall cloning/breeding process.

What's next?

FDA's Risk Assessment includes data collected or published before mid-2007. The FDA will continue to monitor closely the development of clones and their progeny as a source for food as further data become available.

What is the National Academy of Sciences?

The National Academy of Sciences (NAS) was signed into being by President Abraham Lincoln on March 3, 1863, at the height of the Civil War. As mandated in its Act of Incorporation, the NAS has, since 1863, served to "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon to do so by any department of the government. Scientific issues would become even more contentious and complex in the years following the war. To keep pace with the growing roles that science and technology would play in public life, the institution that was founded in 1863 eventually expanded to include the National Research Council in 1916, the National Academy of Engineering in 1964, and the Institute of Medicine in 1970. Collectively, the four organizations are known as the National Academies. Since 1863, the nation's leaders have often turned to the National Academies for advice on the scientific and technological issues that frequently pervade policy decisions. The Academies and the Institute are honorific societies that elect new members to their ranks each year. The Institute of Medicine also conducts policy studies on health issues, but the bulk of the institution's science policy and technical work is conducted by its operating arm, the National Research Council, created expressly for this purpose. These non-profit organizations provide a public service by working outside the framework of government to ensure independent advice on matters of science, technology, and medicine. They enlist committees of the nation's top scientists, engineers, and other experts--all of whom volunteer their time to study specific concerns. (From the National Academy of Sciences website.)

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A Primer on Cloning and Its Use in Livestock Operations

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The responses to the questions provided in this document represent the FDA's view in light of the conclusions and recommendations outlined in the Animal Cloning Risk Assessment, Risk Management Plan, and Guidance for Industry #179. What is cloning, really? What can go wrong with cloning? Why is there interest in cloning?

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Animals and Plants

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Artificial Selection is a form of selection in which humans actively choose which traits should be passed onto offspring. Humans have used selective breeding long before Darwin's Postulates and the discovery of genetics. Farmers chose cattle with beneficial traits such as larger size or producing more milk, and made them breed; and although they may have known nothing about genes, they knew that the beneficial traits could be heritable. The farmers selected for certain traits in their cattle and probably noticed that the offspring were becoming more and more productive with each generation. Scientists study these traits and spend a lot of time calculating how heritable these traits can be. The more these traits are expressed in the offspring (i.e. size, milk production, etc), the more heritable these traits are said to be. Hunting is also a form of artificial selection, with the genes that humans "want" (i.e. - the biggest buck with the most points, the largest fish, etc.) being removed from the gene pool, allowing the less "wanted" genes to pass on to the next generation by increasing their odds of mating when compared to the hunted specimens.

Here is an interesting article that outlines some of the advantages and disadvantages of artificial selection.

Here is a website from Berkeley outlining artificial selection.

Here's an example of selective breeding on a farm.

Cats

If one were to produce a type of hypoallergenic cat, how would one go about doing it? ( Article) Start with a population of short-haired cats that have been tested with humans who are allergic to cats. Breed the cats that cause the least allergic reaction. Test the offspring with allergic humans and select the ones with the least effect. Continue choosing the least allergy-generating cats to reproduce. The traits that provoke allergies are weeded out, but the resulting breed will probably not be entirely hypoallergenic. Animals without fur are said to have fewer of the allergens that irritate and cause symptoms, however they aren't completely hypoallergenic.

Breeders have also used selective breeding to create exotic pets. In this case, the breeder crossbreeds two different species-- such as the serval and the domestic cat to produce the Savannah cat. Like many other hybrids, many offspring are sterile. Most infertility in hybrids is caused by a difference in chromosome count between the species. F1 generation Savannahs are very difficult to produce due to differences in gestation time and picky mate selection in servals. This can lead to obvious problems that result in aborted pregnancies or kittens born prematurely. Many of the Savannah cats are back-crosses of the F1 to a serval, which produces a cat that is a higher percentage serval. The Savannahs are not all infertile, depending on their genetics, but male Savannahs are infertile until the F5 generation, while females are fertile from the F1 generation. This link shows what a Savannah cat is, along with other interesting hybrid pets!

Dogs

As purebred dogs are becoming increasingly inbred, problems are arising from a genetic standpoint. The frequency of being homozygous for rare recessive disorders increases when inbreeding occurs, potentially causing severe health problems down the road.

Most, if not all, breeds of household dogs that exist today are due to artificial/selective breeding. The original bloodline is from wolf-like animals that were domesticated and bred for more docile traits. Now we have everything from mastiffs to poodles. Here is a link explaining this selection in greater detail.

A notable fact about the speciation of dogs and wolves is that what we know as the domestic dog is actually a subspecies of the Gray wolf, Canis lupus; domestic dogs are known as Canis lupus familiarus.

This study was begun in 1959 by a Soviet geneticist, who sought to replicate domestication practices in a species not domesticated before, the silver fox. Tameness was the only trait selected for throughout the study, which scientists still continue to do today. Now, the physical characteristics of the foxes have changed from the originals, ranging from a difference in coat color, to floppy ears, to eagerness to please the humans they interact with.

This article about how dogs evolved from a common ancestor with wolves suggests that old wolves evolved into domestication as they started living closer to humans. Dr. Ya-Ping Zhang suggests that wolves started scavenging from carcasses left by human populations. The more aggressive wolves would be killed while the more mellow wolves would be allowed to eat from the carcasses and stay in close proximity to humans. Domesticated dogs evolved their genes in many different directions than normal wolves, and many of these genes are active in dogs' brain. Many of these genes that underwent selection in domesticated dogs also underwent selection in human brains too.

Another interesting and relevant fact about artificial selection: dogs have the widest range of phenotype of any mammal! The structure of the breed can help solve problems in regards to disease heterogeneity in humans.

Here is a link to a BBC documentary that explains the issues with inbreeding dogs and the medical/health impact of selective breeding. These negative effects have spurred a movement for hybrid dogs recently as genetic diversity increases by combining two breeds of dogs.

This picture gives a visual representation of the evolution of our beloved bulldog.

The skull on the right is from 1800 and the left is from 1904, and represents the breed as we know it today.

The New York Times even wrote an article about our beloved mascot's genetic transformation: " It is the most extreme example of genetic manipulation in the dog-breeding world that results in congenital and hereditary problems."

Pug dogs that have been bred for certain traits often develop breathing problems. Is it right for breeders to continue this just for their own incomes? Watch this video to get some insight.

NOTE: Not just pugs have problems due to breeding. Many pure breeds have problems. For example Labradors experience hip dysplasia, great danes have heart problems, etc. Many big dog breeds suffer from arthritis. Labradors often have problems with their hips.

Here is a great Nature news article on the effect of human selection on the dog genome and its future implications.

Dogs have a sliding genome composed of many, many transposable elements.

Here is an article going into further detail about the genetics of dog breeding.

Here is extra evidence of artificial selection in dogs.

Farm Animals

There has been artificial selection pressure on animals due to human intervention, first dating back to the use of castration to control the behavior of aggressive males. Additionally, in the early stages and in some species continuing today, humans routinely chose to kill and eat animals whose behavior was difficult to control before they had a chance to reproduce. For the time people have controlled domestic animals, the selective pressure has been related to the animals' behavior. At first, more tractable behavior occurred more as a consequence of human attempts to control behavior, not as planned, conscious acts to produce tamer, more tractable animals ( Belyaev 1978). This unintentional selection also encouraged social behavior so that individuals that stayed together in herds and flocks were favored, as would individuals that exhibited tolerance to people. Other techniques employed since early stages of domestication, such as cross-fostering of young and early weaning, also affected maternal behavior of livestock. Domestic hens are known to be more likely to accept chicks hatched from eggs of other species than are wild birds ( Lorenz 1965).

Farmers continue to employ artificial selection. They breed animals in order to improve productivity and thus profits. For example, dairy farmers will look for the cows that can produce the most milk and only breed those cows. These cows then pass their genes that contribute to higher milk production onto their offspring, increasing productivity each generation for the farmers.

Animation explaining selective breeding by farmers.

Here is a Scholarly Article that focuses on showing the complexity of livestock domestication.

Fish

Due to fishing regulations dictating that only the largest fish may be kept, humans are artificially selecting fish to produce smaller size fish. ( Article) Originally there was great variation in fish size. As the population was fished, only large fish were removed, while smaller fish remained. Small fish reproduce and produce more small fish. Population will continue to decrease in size so long as the largest fish are harvested. " Slot limits" are often imposed preventing the harvest of fish over a certain size to counter this effect.

Example: the wild mustard crop was artificially selected to cultivate many different popular crops.

Here is another example that takes place right here on UGA's campus. It looks at bees as pollinators, as well as the reproductive success of apple orchards, blue berries, cantaloupe, cucumber, squash, watermelon, and more.

Humans have been using agriculture and cross pollinating to manipulate the genomes of different plant species, especially wheat, whose chromosomal number increased as agriculture progressed. This kind of manipulation is responsible for foods like seedless watermelons and other seedless fruit. (for example: a banana is triploid, having 2 sets of chromosomes from one parent and 1 set of chromosomes from the other parent, these triploids don't really produce egg/sperm with balanced chromosomes so a seed set is rare thus leading to a banana with no seeds).

The artificial breeding of crops over many centuries has led to humans using only a few strains of each of the major crops, such as corn, worldwide. This has raised concerns because if an epidemic passed through a certain strain or group of strains for one of mankind's major crops, such as ice or corn, it could destroy a huge portion of the world's food supply. As a result, many scientists stress the usage of a variety of crop species and the cultivation and preservation of the closest living relative to our food crops' ancestor.

Artificial selection on peaches. video

Artificial Selection on bananas.

Examples of Artificial Selection from Class

Tomatoes were bred fromthe size of blueberries to the modern size.

Maize was bred from an unfamiliar tall grass-like plant called Teosinte. Larger and fuller kernels were selected for in order to allow the crop to be a more effective food source.

Picture Website
Brassica olercea can be bred into broccoli, cauliflower, Brussels sprouts, cabbage, collard greens, and more.

- GMOs are genetically modified organisms that are engineered to contain foreign DNA that the organism could not obtain in traditional breeding, usually to introduce a beneficial trait. For example, some GMO plants are artificially selected to produce its own insecticide, so that the yield of crops is bigger and more beneficial to the farmers. Some examples of crops that have been genetically modified are:

Corn - insect resistance

Soybeans - herbicide tolerance

Rice - vitamin enrichment (beta-carotene aka vitamin A)

Potatoes - virus resistance

The Flavr Savr Tomato: The Flavr Savr tomato was the first genetically engineered food product to be released to the market. The goal of the Flavr Savr genetic alterations was to slow the ripening process, thus preventing the tomato from becoming soft, while still retaining its natural color and flavor. However, despite the tomato possessing these characteristics it was a huge failure. The tomato that was selected to experiment on was originally of inferior taste and flavor. The GMO tomato that was created was simply a more durable form of a terrible tomato.

- GMOs have also shown great potential for medicinal uses and other applications through the modification of microbes. These were the first organisms to be genetically modified in a laboratory setting due to their relatively simplistic genomes. Some uses include:

Culture of pure human proteins

Large scale insulin production for diabetics

Biofuel production

Hemophilia treatme nts

Interesting video telling how to identify GMO's.

Breeder's Equation

In class, we learned about the breeder's equation:

R= h^2*S

In the equation, 'R' is the response, or the average difference between a parent generation and the offspring generation, 'h^2' is narrow sense heritability, and 'S' is selection, which is the average difference between the parent generation and individuals selected to breed.

Breeder's Equation asks, "If the environment selects for a heritable trait, how will the population respond (Wares 2013)?" Thus, the breeder's equation calculates the change in alleles between generations. The breeder's equation has been used innately for longer than the equation was created. Breeders have always selected and bred animals or crops that possessed favorable traits.

Broad Sense Heritability (H^2) includes all types of genetic variance while Narrow Sense heritability only considers additive genetic variance.

Some basic information through Duke University about the Breeder's Equation.

Here's an interactive video from Duke University that explains the Breeder's Equation: http://www.youtube.com/watch?v=Y24OuELiih0

Artificial Selection in Plant Breeding

The full article from Science Daily is available here

Desired genotypes and phenotypes of various plant species can be achieved through the purposeful manipulation of breeding.

This manipulation can include controlled pollination or genetic engineering (or both) followed by artificial selection of progeny.

Many agencies believe that breeding new crops is essential to ensuring food security and developing plants more suitable to given environments.

Classical plant breeding uses deliberate plant interbreeding to produce new crop varieties with desirable properties.

Allows for the introduction of traits and/or genes from one variety or line into a new genetic background.

Progeny would then be crossed with the high yielding parent to ensure that the progeny were most like the high yielding parent (backcrossing).

Plants can also be crossed with themselves to produce inbred varieties.

Disadvantages of Artificial Selection

Artificial selection can create organisms that are dangerous to the population. For example, killer bees, also known as Africanized honey bees, were bred to produce more honey, but have killed a couple of people due to the unforeseen trait of increased aggressiveness being passed on. In some cases, like the banana, artificial selection has led to sterility. The author of this article argues against the ability to selectively breed and artificially select.

Artificial selection also removes variation in a population (Nature of Life).

Can create new mutations.

Can perpetuate harmful mutations.

Very expensive.

Can cause harm to the animals that are being bred such as a shorter life span.

Saving Coral Reefs through Selective Selection

This article describes a new approach to save coral reefs through selectively breeding corals which are more resistant to acidity and warmer temperatures. This approach is controversial because it is taking a serious issue and creating a temporary fix. Solutions should be sought in terms of lowering CO2 levels and restoring the oceans to their prior state. On the other hand, these types of changes may be unstoppable and thus having backup solutions such as selective breeding of corals will prove useful in retaining some level of the original community structure.

/groups/evol3000/search/index.rss?tag=hotlist/groups/evol3000/search/?tag=hotWhat's HotHotListHot!?tag=hot14/groups/evol3000/sidebar/HotListliishiiliishii2013-12-10 01:58:20+00:002013-12-10 01:58:20updated159smithasmitha2013-11-25 00:37:02+00:002013-11-25 00:37:02updated158edit8: added a like to the course evaluations on this page jlri228jlri2282013-11-24 22:26:27+00:002013-11-24 22:26:27updated157edit7: removed duplicate "human evolution page" and transferred content to original "human evolution pagejlri228jlri2282013-11-24 22:24:02+00:002013-11-24 22:24:02updated156moved the oxytocin link in the other random pages in order to keep the alphabetical order jlri228jlri2282013-11-24 21:41:40+00:002013-11-24 21:41:40updated155melissa4melissa42013-11-19 02:34:17+00:002013-11-19 02:34:17updated154eidt11: kept the alphabetical order of the "other random pages section"jlri228jlri2282013-11-18 04:39:34+00:002013-11-18 04:39:34updated153ahakimahakim2013-11-18 04:29:20+00:002013-11-18 04:29:20updated152bhinton1bhinton12013-11-16 02:22:16+00:002013-11-16 02:22:16updated151bhinton1bhinton12013-11-16 02:21:46+00:002013-11-16 02:21:46updated150naa92naa922013-11-15 16:56:42+00:002013-11-15 16:56:42updated149corrected the spelling of neighbor in the "other random pages section" and fixed the title to match the current format jlri228jlri2282013-11-15 03:05:48+00:002013-11-15 03:05:48updated148put the "other random pages" section in alaphabetical order jlri228jlri2282013-11-15 03:01:22+00:002013-11-15 03:01:22updated147rearragned the wiki pages so that they remained in alaphabetical order jlri228jlri2282013-11-15 02:57:51+00:002013-11-15 02:57:51updated146linked in wiki page o 23 and me instead of company website.philogeaphilogea2013-11-13 21:19:01+00:002013-11-13 21:19:01updated145linked discussion page to discussion announcementphilogeaphilogea2013-11-13 21:15:08+00:002013-11-13 21:15:08updated144abutchabutch2013-11-12 19:29:10+00:002013-11-12 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20:43:29updated130dottie94dottie942013-10-30 14:36:41+00:002013-10-30 14:36:41updated129lgcarterlgcarter2013-10-28 17:42:35+00:002013-10-28 17:42:35updated128edwards9edwards92013-10-28 03:00:50+00:002013-10-28 03:00:50updated127edwards9edwards92013-10-28 02:55:04+00:002013-10-28 02:55:04updated126edwards9edwards92013-10-28 02:49:02+00:002013-10-28 02:49:02updated125edwards9edwards92013-10-28 02:43:10+00:002013-10-28 02:43:10updated124jlri228jlri2282013-10-27 23:00:38+00:002013-10-27 23:00:38updated123edit 4: kept the overall alphabetical order theme for this page jlri228jlri2282013-10-27 22:59:45+00:002013-10-27 22:59:45updated122bhinton1bhinton12013-10-25 19:36:16+00:002013-10-25 19:36:16updated121added linkddphanddphan2013-10-24 15:05:22+00:002013-10-24 15:05:22updated120jlri228jlri2282013-10-21 02:47:11+00:002013-10-21 02:47:11updated119added general discussion page to the "wiki pages" home page jlri228jlri2282013-10-21 02:45:22+00:002013-10-21 02:45:22updated118edit 5: kept pages in alphabetical order... frameshift before gene flowjlri228jlri2282013-10-21 01:31:42+00:002013-10-21 01:31:42updated117allie633allie6332013-10-20 21:27:10+00:002013-10-20 21:27:10updated116achenachen2013-10-20 06:18:02+00:002013-10-20 06:18:02updated115Changed formating on each of the list headingswtownewtowne2013-10-20 04:46:35+00:002013-10-20 04:46:35updated114deerandeeran2013-10-20 04:36:20+00:002013-10-20 04:36:20updated113bhinton1bhinton12013-10-19 23:15:35+00:002013-10-19 23:15:35updated112ddphanddphan2013-10-19 19:25:15+00:002013-10-19 19:25:15updated111Added Linkddphanddphan2013-10-17 14:52:47+00:002013-10-17 14:52:47updated110edit 2: put "other random pages" section in alphabetical order jlri228jlri2282013-10-13 18:37:21+00:002013-10-13 18:37:21updated109jlri228jlri2282013-10-13 18:32:34+00:002013-10-13 18:32:34updated108first edit: put new pages in alphabetical orderjlri228jlri2282013-10-13 18:27:45+00:002013-10-13 18:27:45updated107bhinton1bhinton12013-10-13 15:41:09+00:002013-10-13 15:41:09updated106fgkatzfgkatz2013-10-10 19:43:54+00:002013-10-10 19:43:54updated105fgkatzfgkatz2013-10-10 19:43:14+00:002013-10-10 19:43:14updated104pjung24pjung242013-10-10 16:30:35+00:002013-10-10 16:30:35updated103pgriff10pgriff102013-10-10 15:27:48+00:002013-10-10 15:27:48updated102Added Linksddphanddphan2013-10-10 15:18:28+00:002013-10-10 15:18:28updated101pjung24pjung242013-10-09 21:35:17+00:002013-10-09 21:35:17updated100cryssongcryssong2013-10-09 18:36:27+00:002013-10-09 18:36:27updated99added linksddphanddphan2013-10-08 15:22:26+00:002013-10-08 15:22:26updated98Moved chi-square test to appropriate categorytrostelstrostels2013-10-06 19:29:28+00:002013-10-06 19:29:28updated97put "the bounty: founder effect example" in alphabetical orderjlri228jlri2282013-10-06 03:11:31+00:002013-10-06 03:11:31updated96ddphanddphan2013-10-05 16:35:27+00:002013-10-05 16:35:27updated95pjung24pjung242013-10-03 16:44:39+00:002013-10-03 16:44:39updated94Added Linkddphanddphan2013-10-03 15:15:29+00:002013-10-03 15:15:29updated93pjung24pjung242013-10-02 23:29:01+00:002013-10-02 23:29:01updated92formatting changesjlri228jlri2282013-09-30 01:12:07+00:002013-09-30 01:12:07updated91For my second post i added the newly created page to the Wiki pages section jlri228jlri2282013-09-30 01:01:23+00:002013-09-30 01:01:23updated90bhinton1bhinton12013-09-29 02:25:22+00:002013-09-29 02:25:22updated89bhinton1bhinton12013-09-29 02:20:01+00:002013-09-29 02:20:01updated88fgkatzfgkatz2013-09-27 15:34:25+00:002013-09-27 15:34:25updated87alphebetized the listtrostelstrostels2013-09-26 23:38:31+00:002013-09-26 23:38:31updated86delete unnecessary linkskjanekjane2013-09-26 21:57:19+00:002013-09-26 21:57:19updated85kjanekjane2013-09-26 21:43:56+00:002013-09-26 21:43:56updated84kjanekjane2013-09-26 21:39:39+00:002013-09-26 21:39:39updated83moved epistasis linkkjanekjane2013-09-26 21:39:11+00:002013-09-26 21:39:11updated82Made a link to the new Inbreeding pageagdeleoagdeleo2013-09-26 17:02:55+00:002013-09-26 17:02:55updated81Deleted the link to "Important Faces" page since the page no longer existsagdeleoagdeleo2013-09-26 16:40:25+00:002013-09-26 16:40:25updated80kdsouza9kdsouza92013-09-24 16:03:26+00:002013-09-24 16:03:26updated79Added Pagesddphanddphan2013-09-24 15:39:13+00:002013-09-24 15:39:13updated78added stickleback evolution page linkkdsouza9kdsouza92013-09-24 15:37:18+00:002013-09-24 15:37:18updated77glynchglynch2013-09-23 03:00:01+00:002013-09-23 03:00:01updated76glynchglynch2013-09-23 02:59:20+00:002013-09-23 02:59:20updated75glynchglynch2013-09-23 02:56:12+00:002013-09-23 02:56:12updated74jlri228jlri2282013-09-22 22:38:02+00:002013-09-22 22:38:02updated73moved heritability section into correct alphabetical ordering jlri228jlri2282013-09-22 22:37:46+00:002013-09-22 22:37:46updated72adwomackadwomack2013-09-22 02:45:05+00:002013-09-22 02:45:05updated71bhinton1bhinton12013-09-22 02:23:18+00:002013-09-22 02:23:18updated70bhinton1bhinton12013-09-22 02:19:02+00:002013-09-22 02:19:02updated69delete duplicate page linkkjanekjane2013-09-20 19:12:57+00:002013-09-20 19:12:57updated68fgkatzfgkatz2013-09-20 15:46:17+00:002013-09-20 15:46:17updated67baek92baek922013-09-19 20:50:17+00:002013-09-19 20:50:17updated66pjung24pjung242013-09-19 16:49:00+00:002013-09-19 16:49:00updated65katmoor4katmoor42013-09-19 12:06:40+00:002013-09-19 12:06:40updated64adwomackadwomack2013-09-19 02:11:23+00:002013-09-19 02:11:23updated63Added better description of linkjnunez26jnunez262013-09-18 23:39:06+00:002013-09-18 23:39:06updated62jnunez26jnunez262013-09-18 23:36:31+00:002013-09-18 23:36:31updated61jnunez26jnunez262013-09-18 23:09:07+00:002013-09-18 23:09:07updated60added a linkginasanginasan2013-09-18 05:06:15+00:002013-09-18 05:06:15updated59added linkginasanginasan2013-09-18 02:49:03+00:002013-09-18 02:49:03updated58Added pagesddphanddphan2013-09-17 15:11:29+00:002013-09-17 15:11:29updated57added a linkginasanginasan2013-09-17 03:56:06+00:002013-09-17 03:56:06updated56ginasanginasan2013-09-15 18:14:39+00:002013-09-15 18:14:39updated55added a linkginasanginasan2013-09-15 16:54:07+00:002013-09-15 16:54:07updated54dmdauerdmdauer2013-09-15 15:04:59+00:002013-09-15 15:04:59updated53added linkginasanginasan2013-09-14 22:06:05+00:002013-09-14 22:06:05updated52bjenk07bjenk072013-09-14 01:50:26+00:002013-09-14 01:50:26updated51naa92naa922013-09-14 01:12:59+00:002013-09-14 01:12:59updated50Added Linksddphanddphan2013-09-12 15:18:40+00:002013-09-12 15:18:40updated49Added linksddphanddphan2013-09-10 15:12:39+00:002013-09-10 15:12:39updated48fgkatzfgkatz2013-09-09 16:49:54+00:002013-09-09 16:49:54updated47najjar22najjar222013-09-09 13:30:38+00:002013-09-09 13:30:38updated46Linked newly created page on epigenetics to wiki pages master page jlri228jlri2282013-09-09 03:51:39+00:002013-09-09 03:51:39updated45added 'Evolutionary Response' page linktrostelstrostels2013-09-09 01:48:26+00:002013-09-09 01:48:26updated44bhinton1bhinton12013-09-08 22:30:51+00:002013-09-08 22:30:51updated43bhinton1bhinton12013-09-08 22:30:03+00:002013-09-08 22:30:03updated42added another linkginasanginasan2013-09-08 16:15:37+00:002013-09-08 16:15:37updated41added 3 linksginasanginasan2013-09-08 16:11:26+00:002013-09-08 16:11:26updated40achenachen2013-09-06 21:27:24+00:002013-09-06 21:27:24updated39Relinked genetic drift pagepjung24pjung242013-09-06 20:34:45+00:002013-09-06 20:34:45updated38baek92baek922013-09-05 21:11:55+00:002013-09-05 21:11:55updated37allie633allie6332013-09-05 18:27:14+00:002013-09-05 18:27:14updated36allie633allie6332013-09-05 18:24:22+00:002013-09-05 18:24:22updated35allie633allie6332013-09-05 18:23:28+00:002013-09-05 18:23:28updated34allie633allie6332013-09-05 18:11:00+00:002013-09-05 18:11:00updated33allie633allie6332013-09-05 18:04:41+00:002013-09-05 18:04:41updated32allie633allie6332013-09-05 17:55:19+00:002013-09-05 17:55:19updated31allie633allie6332013-09-05 17:53:18+00:002013-09-05 17:53:18updated30allie633allie6332013-09-05 17:47:46+00:002013-09-05 17:47:46updated29organizationddphanddphan2013-09-05 15:30:50+00:002013-09-05 15:30:50updated28Added tag - hotddphanddphan2013-09-05 15:30:47+00:002013-09-05 15:30:47addTag27ddphanddphan2013-09-05 15:25:55+00:002013-09-05 15:25:55updated26adding links to new pagescharleebcharleeb2013-09-05 15:05:14+00:002013-09-05 15:05:14updated25fgkatzfgkatz2013-09-04 17:20:39+00:002013-09-04 17:20:39updated24fgkatzfgkatz2013-09-04 17:19:05+00:002013-09-04 17:19:05updated23fgkatzfgkatz2013-09-04 17:18:11+00:002013-09-04 17:18:11updated22fgkatzfgkatz2013-09-04 17:17:27+00:002013-09-04 17:17:27updated21fgkatzfgkatz2013-09-04 17:16:40+00:002013-09-04 17:16:40updated20bhinton1bhinton12013-09-04 00:43:13+00:002013-09-04 00:43:13updated19daileycodaileyco2013-09-02 22:39:29+00:002013-09-02 22:39:29updated18added links and rearrangedginasanginasan2013-09-02 01:25:38+00:002013-09-02 01:25:38updated17added linkginasanginasan2013-09-02 01:17:36+00:002013-09-02 01:17:36updated16robertprobertp2013-09-01 19:22:15+00:002013-09-01 19:22:15updated15deerandeeran2013-08-31 20:03:41+00:002013-08-31 20:03:41updated14mia2016mia20162013-08-29 19:01:48+00:002013-08-29 19:01:48updated13fgkatzfgkatz2013-08-29 19:01:00+00:002013-08-29 19:01:00updated12fgkatzfgkatz2013-08-29 19:00:00+00:002013-08-29 19:00:00updated11fgkatzfgkatz2013-08-29 18:59:10+00:002013-08-29 18:59:10updated10fgkatzfgkatz2013-08-29 18:57:47+00:002013-08-29 18:57:47updated9fgkatzfgkatz2013-08-29 18:35:32+00:002013-08-29 18:35:32updated8fgkatzfgkatz2013-08-29 18:34:35+00:002013-08-29 18:34:35updated7lgcarterlgcarter2013-08-29 16:08:07+00:002013-08-29 16:08:07updated6Created Pageddphanddphan2013-08-28 01:50:51+00:002013-08-28 01:50:51updated5Added tag - wikiddphanddphan2013-08-28 01:44:43+00:002013-08-28 01:44:43addTag4Added tag - sand boxddphanddphan2013-08-28 01:44:41+00:002013-08-28 01:44:41addTag3Added tag - discussionddphanddphan2013-08-28 01:44:38+00:002013-08-28 01:44:38addTag2First createdddphanddphan2013-08-28 01:43:31+00:002013-08-28 01:43:31created1wiki2013-12-10T01:58:20+00:00groups/evol3000/wiki/54e13FalseWiki Pages/groups/evol3000/wiki/54e13/Wiki_Pages.htmlliishii159 updatesWiki Pages PLEASE READ: Commenting on the wiki pages do not count as participation credit on the wiki. The directions in the syllabus are clear on what does...Falseliishii2013-12-10T01:58:20+00:00added an exampleduggan91duggan912013-11-25 22:18:09+00:002013-11-25 22:18:09updated92souyang1souyang12013-11-25 05:00:00+00:002013-11-25 05:00:00updated91ashleyjwashleyjw2013-11-25 04:17:05+00:002013-11-25 04:17:05updated90mpattmpatt2013-11-25 04:10:42+00:002013-11-25 04:10:42updated89tabedintabedin2013-11-24 23:37:00+00:002013-11-24 23:37:00updated88edit 5: added video to "infecting a host section"jlri228jlri2282013-11-24 22:07:33+00:002013-11-24 22:07:33updated87edit4: made formatting changes and added a video on viral reassortment jlri228jlri2282013-11-24 22:04:13+00:002013-11-24 22:04:13updated86added articlekkogantikkoganti2013-11-24 17:45:38+00:002013-11-24 17:45:38updated85samponssampons2013-11-24 03:53:13+00:002013-11-24 03:53:13updated84deerandeeran2013-11-23 23:02:22+00:002013-11-23 23:02:22updated83tvashitvashi2013-11-23 04:25:36+00:002013-11-23 04:25:36updated82kde04kde042013-11-22 22:40:46+00:002013-11-22 22:40:46updated81kde04kde042013-11-22 22:39:59+00:002013-11-22 22:39:59updated80eyang13eyang132013-11-22 18:03:27+00:002013-11-22 18:03:27updated79eyang13eyang132013-11-22 18:03:11+00:002013-11-22 18:03:11updated78pjung24pjung242013-11-22 17:43:52+00:002013-11-22 17:43:52updated77pjung24pjung242013-11-22 17:38:38+00:002013-11-22 17:38:38updated76gloriaszgloriasz2013-11-22 17:37:21+00:002013-11-22 17:37:21updated75gloriaszgloriasz2013-11-22 17:36:24+00:002013-11-22 17:36:24updated74sydneyb9sydneyb92013-11-21 22:23:02+00:002013-11-21 22:23:02updated73re320re3202013-11-21 19:25:53+00:002013-11-21 19:25:53updated72bpcroftbpcroft2013-11-21 16:58:19+00:002013-11-21 16:58:19updated71bpcroftbpcroft2013-11-21 16:56:30+00:002013-11-21 16:56:30updated70tcard4tcard42013-11-21 15:20:30+00:002013-11-21 15:20:30updated69editing and improingbscurrybscurry2013-11-21 05:35:49+00:002013-11-21 05:35:49updated68kristy7kristy72013-11-21 01:02:26+00:002013-11-21 01:02:26updated67kncox14kncox142013-11-20 20:07:04+00:002013-11-20 20:07:04updated66kncox14kncox142013-11-20 20:05:26+00:002013-11-20 20:05:26updated65kncox14kncox142013-11-20 20:03:10+00:002013-11-20 20:03:10updated64kncox14kncox142013-11-20 19:59:28+00:002013-11-20 19:59:28updated63dmdauerdmdauer2013-11-20 19:58:35+00:002013-11-20 19:58:35updated62added an example of co-evolutionksuf615ksuf6152013-11-20 16:01:14+00:002013-11-20 16:01:14updated61formattingksuf615ksuf6152013-11-20 16:00:32+00:002013-11-20 16:00:32updated60added type of transmissionksuf615ksuf6152013-11-20 16:00:11+00:002013-11-20 16:00:11updated59tbrownetbrowne2013-11-20 03:28:19+00:002013-11-20 03:28:19updated58Nicole Hill- transmission picturenhill19nhill192013-11-19 00:59:47+00:002013-11-19 00:59:47updated57Nicole Hill- viral evolutionnhill19nhill192013-11-19 00:57:38+00:002013-11-19 00:57:38updated56bjenk07bjenk072013-11-18 22:35:01+00:002013-11-18 22:35:01updated55kevinmkkevinmk2013-11-18 22:33:41+00:002013-11-18 22:33:41updated54kevinmkkevinmk2013-11-18 22:26:49+00:002013-11-18 22:26:49updated53kevinmkkevinmk2013-11-18 22:24:06+00:002013-11-18 22:24:06updated52edited paragraph haliejhaliej2013-11-18 15:42:45+00:002013-11-18 15:42:45updated51edited and elongated sentencehaliejhaliej2013-11-18 15:41:32+00:002013-11-18 15:41:32updated50added crucial details on the trade off hypothesis. Took out wrong information. Corrected it.huangdevhuangdev2013-11-18 05:38:51+00:002013-11-18 05:38:51updated49samponssampons2013-11-18 05:31:41+00:002013-11-18 05:31:41updated48bpcroftbpcroft2013-11-18 04:58:03+00:002013-11-18 04:58:03updated47zaki007zaki0072013-11-18 04:55:37+00:002013-11-18 04:55:37updated46ebythekkebythekk2013-11-18 04:16:14+00:002013-11-18 04:16:14updated45jlri228jlri2282013-11-18 04:05:35+00:002013-11-18 04:05:35updated44edit10: more page formatting... moved "types of transmission section"jlri228jlri2282013-11-18 04:05:03+00:002013-11-18 04:05:03updated43kdsouza9kdsouza92013-11-18 04:04:49+00:002013-11-18 04:04:49updated42edit 9: added headers, outlined in blue, rearranged the page in a logical order... reworded some of the content jlri228jlri2282013-11-18 04:01:07+00:002013-11-18 04:01:07updated41ginasanginasan2013-11-18 03:37:17+00:002013-11-18 03:37:17updated40mayabasumayabasu2013-11-18 03:31:22+00:002013-11-18 03:31:22updated39melissa4melissa42013-11-18 03:22:12+00:002013-11-18 03:22:12updated38added extra info about self-containing diseasesbscurrybscurry2013-11-18 03:18:20+00:002013-11-18 03:18:20updated37jsafkojsafko2013-11-18 03:08:38+00:002013-11-18 03:08:38updated36abarton6abarton62013-11-18 01:42:16+00:002013-11-18 01:42:16updated35alomasalomas2013-11-17 23:38:56+00:002013-11-17 23:38:56updated34Contentrbaskin1rbaskin12013-11-17 21:08:09+00:002013-11-17 21:08:09updated33rbaskin1rbaskin12013-11-17 21:07:24+00:002013-11-17 21:07:24updated32Added tag - virulencedmdauerdmdauer2013-11-17 21:06:34+00:002013-11-17 21:06:34addTag31Removed tag - evolutiondmdauerdmdauer2013-11-17 21:06:24+00:002013-11-17 21:06:24removeTag30Added tag - virus evolutiondmdauerdmdauer2013-11-17 21:06:22+00:002013-11-17 21:06:22addTag29dmdauerdmdauer2013-11-17 20:19:02+00:002013-11-17 20:19:02updated28rachel08rachel082013-11-17 18:47:54+00:002013-11-17 18:47:54updated27added a diagramduggan91duggan912013-11-17 14:25:10+00:002013-11-17 14:25:10updated26added cycles of virusduggan91duggan912013-11-17 14:19:13+00:002013-11-17 14:19:13updated25pjung24pjung242013-11-16 20:16:54+00:002013-11-16 20:16:54updated24pjung24pjung242013-11-16 20:15:54+00:002013-11-16 20:15:54updated23pjung24pjung242013-11-16 20:15:13+00:002013-11-16 20:15:13updated22gloriaszgloriasz2013-11-16 14:44:03+00:002013-11-16 14:44:03updated21gloriaszgloriasz2013-11-16 14:43:29+00:002013-11-16 14:43:29updated20gloriaszgloriasz2013-11-16 04:25:39+00:002013-11-16 04:25:39updated19edit3: added the Videos, articles and diagrams hedding... also linked in and explaind two yuotube videosjlri228jlri2282013-11-15 04:16:12+00:002013-11-15 04:16:12updated18kristy7kristy72013-11-14 23:34:04+00:002013-11-14 23:34:04updated17eliminated unnecessary bullet pointddphanddphan2013-11-14 21:28:35+00:002013-11-14 21:28:35updated16Added tag - hotabutchabutch2013-11-14 21:26:06+00:002013-11-14 21:26:06addTag15Added tag - evolutionabutchabutch2013-11-14 21:25:36+00:002013-11-14 21:25:36addTag14abutchabutch2013-11-14 21:01:55+00:002013-11-14 21:01:55updated13abutchabutch2013-11-14 20:58:35+00:002013-11-14 20:58:35updated12abutchabutch2013-11-14 20:47:44+00:002013-11-14 20:47:44updated11alomasalomas2013-11-13 18:34:01+00:002013-11-13 18:34:01updated10mia2016mia20162013-11-13 17:50:07+00:002013-11-13 17:50:07updated9Nicole Hill- hiv viral evolutionnhill19nhill192013-11-13 15:57:54+00:002013-11-13 15:57:54updated8Added an additional point of how growth rate corresponds to virulence within the point on More Virulent Pathogensagdeleoagdeleo2013-11-13 14:45:57+00:002013-11-13 14:45:57updated7kdv11kdv112013-11-13 13:42:02+00:002013-11-13 13:42:02updated6reemap26reemap262013-11-13 00:56:38+00:002013-11-13 00:56:38updated5khall12khall122013-11-13 00:15:24+00:002013-11-13 00:15:24updated4tvashitvashi2013-11-12 22:29:16+00:002013-11-12 22:29:16updated3abutchabutch2013-11-12 19:28:35+00:002013-11-12 19:28:35updated2First createdabutchabutch2013-11-12 19:18:06+00:002013-11-12 19:18:06created1wiki2013-11-25T22:18:09+00:00groups/evol3000/wiki/fbefaFalseViral Evolution/groups/evol3000/wiki/fbefa/Viral_Evolution.htmlduggan9192 updatesViral Evolution Origins of Viruses/ Viral Transmission Virus Origins: There is a lot of debate on this topic, but scientists have developed a few prop...Falseduggan912013-11-25T22:18:09+00:00mayabasumayabasu2013-11-25 03:26:27+00:002013-11-25 03:26:27updated224dmdauerdmdauer2013-11-25 01:08:29+00:002013-11-25 01:08:29updated223added a linkralbrechralbrech2013-11-25 00:06:17+00:002013-11-25 00:06:17updated222enanovenanov2013-11-18 04:30:22+00:002013-11-18 04:30:22updated221kdsouza9kdsouza92013-11-18 04:01:48+00:002013-11-18 04:01:48updated220article about sexual selectiongagirl11bgagirl11b2013-11-18 03:45:26+00:002013-11-18 03:45:26updated219fixed my own typokkogantikkoganti2013-11-18 02:46:23+00:002013-11-18 02:46:23updated218added article on sperm cooperationkkogantikkoganti2013-11-18 02:42:47+00:002013-11-18 02:42:47updated217nikra91nikra912013-11-18 02:39:04+00:002013-11-18 02:39:04updated216added article on sperm cooperationkkogantikkoganti2013-11-18 02:37:49+00:002013-11-18 02:37:49updated215deerandeeran2013-11-18 02:26:46+00:002013-11-18 02:26:46updated214talathitalathi2013-11-18 00:21:32+00:002013-11-18 00:21:32updated213rachel08rachel082013-11-17 18:29:28+00:002013-11-17 18:29:28updated212deerandeeran2013-11-17 04:00:15+00:002013-11-17 04:00:15updated211formattingjlri228jlri2282013-11-15 04:03:58+00:002013-11-15 04:03:58updated210haislerkhaislerk2013-11-14 22:12:35+00:002013-11-14 22:12:35updated209bevinbbevinb2013-11-13 18:55:52+00:002013-11-13 18:55:52updated208added description to the video somebody posted on sexual selection in human dating scenegregbgregb2013-11-11 05:47:02+00:002013-11-11 05:47:02updated207added info to 2duggan91duggan912013-11-11 05:02:26+00:002013-11-11 05:02:26updated206mayabasumayabasu2013-11-11 04:25:58+00:002013-11-11 04:25:58updated205achenachen2013-11-11 02:01:42+00:002013-11-11 02:01:42updated204ashleyjwashleyjw2013-11-11 00:54:06+00:002013-11-11 00:54:06updated203jsafkojsafko2013-11-11 00:13:19+00:002013-11-11 00:13:19updated202khall12khall122013-11-10 00:31:41+00:002013-11-10 00:31:41updated201corrected a typo physical ---> psycologicaladwomackadwomack2013-11-10 00:02:21+00:002013-11-10 00:02:21updated200added to human sexual selection on the psychological parts of sexual selectionedawg16edawg162013-11-09 23:18:24+00:002013-11-09 23:18:24updated199gloriaszgloriasz2013-11-09 14:19:55+00:002013-11-09 14:19:55updated198gloriaszgloriasz2013-11-09 14:19:03+00:002013-11-09 14:19:03updated197gloriaszgloriasz2013-11-07 19:10:16+00:002013-11-07 19:10:16updated196gloriaszgloriasz2013-11-07 19:09:38+00:002013-11-07 19:09:38updated195tvashitvashi2013-11-07 16:00:27+00:002013-11-07 16:00:27updated194mendyhmendyh2013-11-06 17:44:49+00:002013-11-06 17:44:49updated193added nuptual giftsbennywbennyw2013-11-06 03:47:43+00:002013-11-06 03:47:43updated192organization, deleted redundant titleddphanddphan2013-11-05 16:30:14+00:002013-11-05 16:30:14updated191edwards9edwards92013-11-04 04:19:18+00:002013-11-04 04:19:18updated190amanqua3amanqua32013-11-04 03:25:29+00:002013-11-04 03:25:29updated189samponssampons2013-11-04 03:22:57+00:002013-11-04 03:22:57updated188amanqua3amanqua32013-11-04 03:21:23+00:002013-11-04 03:21:23updated187grammarjsafkojsafko2013-11-04 02:48:38+00:002013-11-04 02:48:38updated186added a link about recent evolution has caused women to prefer the Beta males over the Alpha malescolby22colby222013-11-04 02:09:42+00:002013-11-04 02:09:42updated185kde04kde042013-10-31 10:40:40+00:002013-10-31 10:40:40updated184alhill9alhill92013-10-31 06:55:28+00:002013-10-31 06:55:28updated183kncox14kncox142013-10-31 03:32:47+00:002013-10-31 03:32:47updated182manuelabmanuelab2013-10-30 23:39:37+00:002013-10-30 23:39:37updated181bjenk07bjenk072013-10-30 21:48:03+00:002013-10-30 21:48:03updated180bjenk07bjenk072013-10-30 21:41:53+00:002013-10-30 21:41:53updated179bjenk07bjenk072013-10-30 21:38:17+00:002013-10-30 21:38:17updated178kevinmkkevinmk2013-10-30 21:35:56+00:002013-10-30 21:35:56updated177kevinmkkevinmk2013-10-30 21:32:56+00:002013-10-30 21:32:56updated176kevinmkkevinmk2013-10-30 21:32:44+00:002013-10-30 21:32:44updated175mbailey1mbailey12013-10-29 23:36:45+00:002013-10-29 23:36:45updated174mbailey1mbailey12013-10-29 23:29:04+00:002013-10-29 23:29:04updated173sydneyb9sydneyb92013-10-29 22:38:04+00:002013-10-29 22:38:04updated172Nicole Hill- Sexual selection/conflictnhill19nhill192013-10-29 16:07:17+00:002013-10-29 16:07:17updated171tbrownetbrowne2013-10-28 22:49:29+00:002013-10-28 22:49:29updated170tbrownetbrowne2013-10-28 22:47:07+00:002013-10-28 22:47:07updated169tbrownetbrowne2013-10-28 22:42:24+00:002013-10-28 22:42:24updated168tbrownetbrowne2013-10-28 22:38:54+00:002013-10-28 22:38:54updated167tbrownetbrowne2013-10-28 22:38:14+00:002013-10-28 22:38:14updated166tbrownetbrowne2013-10-28 22:37:21+00:002013-10-28 22:37:21updated165charleebcharleeb2013-10-28 18:35:46+00:002013-10-28 18:35:46updated164tgetztgetz2013-10-28 03:29:40+00:002013-10-28 03:29:40updated163tgetztgetz2013-10-28 03:27:34+00:002013-10-28 03:27:34updated162ebythekkebythekk2013-10-28 03:20:30+00:002013-10-28 03:20:30updated161achenachen2013-10-28 02:28:29+00:002013-10-28 02:28:29updated160kkogantikkoganti2013-10-28 01:51:33+00:002013-10-28 01:51:33updated159Edited section about "why is sex bad" and added explanation of two fold costjkabacijkabaci2013-10-27 23:27:29+00:002013-10-27 23:27:29updated158dmdauerdmdauer2013-10-27 23:04:00+00:002013-10-27 23:04:00updated157edit 3: added an outline for the handout jlri228jlri2282013-10-27 22:49:18+00:002013-10-27 22:49:18updated156edit 2: added handout and paragraph about sexual conflict in guppies jlri228jlri2282013-10-27 22:45:59+00:002013-10-27 22:45:59updated155edit 1: removed mislabeled content and kept formatting the same by making a title bluejlri228jlri2282013-10-27 22:16:04+00:002013-10-27 22:16:04updated154abarton6abarton62013-10-27 21:56:19+00:002013-10-27 21:56:19updated153tchishomtchishom2013-10-27 21:46:05+00:002013-10-27 21:46:05updated152rachel08rachel082013-10-27 21:23:35+00:002013-10-27 21:23:35updated151rachel08rachel082013-10-27 21:21:16+00:002013-10-27 21:21:16updated150jsafkojsafko2013-10-27 21:18:23+00:002013-10-27 21:18:23updated149wording of def for human sex selectionjnunez26jnunez262013-10-27 20:53:20+00:002013-10-27 20:53:20updated148dottie94dottie942013-10-27 17:24:40+00:002013-10-27 17:24:40updated147alhill9alhill92013-10-27 14:22:03+00:002013-10-27 14:22:03updated146shree7shree72013-10-26 21:47:37+00:002013-10-26 21:47:37updated145shree7shree72013-10-26 21:38:58+00:002013-10-26 21:38:58updated144chersh93chersh932013-10-26 17:52:15+00:002013-10-26 17:52:15updated143Added tag - hotpjung24pjung242013-10-26 17:49:06+00:002013-10-26 17:49:06addTag142Removed tag - hotpjung24pjung242013-10-26 17:49:04+00:002013-10-26 17:49:04removeTag141pjung24pjung242013-10-26 04:10:18+00:002013-10-26 04:10:18updated140pjung24pjung242013-10-26 04:07:44+00:002013-10-26 04:07:44updated139tvashitvashi2013-10-26 00:37:32+00:002013-10-26 00:37:32updated138kehoekkehoek2013-10-25 19:46:19+00:002013-10-25 19:46:19updated137kristy7kristy72013-10-25 18:49:50+00:002013-10-25 18:49:50updated136grammarspenc90spenc902013-10-25 16:22:38+00:002013-10-25 16:22:38updated135tcard4tcard42013-10-25 01:52:43+00:002013-10-25 01:52:43updated134pgriff10pgriff102013-10-25 01:14:54+00:002013-10-25 01:14:54updated133gloriaszgloriasz2013-10-25 00:41:16+00:002013-10-25 00:41:16updated132achenachen2013-10-24 21:40:38+00:002013-10-24 21:40:38updated131mia2016mia20162013-10-24 20:28:56+00:002013-10-24 20:28:56updated130ekeatingekeating2013-10-24 19:38:28+00:002013-10-24 19:38:28updated129xjwork17xjwork172013-10-24 15:00:00+00:002013-10-24 15:00:00updated128nkamnkam2013-10-23 15:20:45+00:002013-10-23 15:20:45updated127added a link about sexual seleciton and human sexual selectiongagirl11bgagirl11b2013-10-23 14:19:17+00:002013-10-23 14:19:17updated126tcard4tcard42013-10-22 17:19:41+00:002013-10-22 17:19:41updated125rtalleyrtalley2013-10-22 15:26:58+00:002013-10-22 15:26:58updated124rtalleyrtalley2013-10-22 15:25:32+00:002013-10-22 15:25:32updated123haislerkhaislerk2013-10-22 15:15:20+00:002013-10-22 15:15:20updated122haislerkhaislerk2013-10-22 15:14:49+00:002013-10-22 15:14:49updated121haislerkhaislerk2013-10-22 15:12:14+00:002013-10-22 15:12:14updated120haislerkhaislerk2013-10-22 15:09:22+00:002013-10-22 15:09:22updated119mbelyakombelyako2013-10-21 23:34:18+00:002013-10-21 23:34:18updated118Nicole Hill-Sexual section imagenhill19nhill192013-10-21 21:24:41+00:002013-10-21 21:24:41updated117ashleydgashleydg2013-10-21 03:25:30+00:002013-10-21 03:25:30updated116ashleydgashleydg2013-10-21 03:10:58+00:002013-10-21 03:10:58updated115ashleydgashleydg2013-10-21 03:10:24+00:002013-10-21 03:10:24updated114edited articlejsafkojsafko2013-10-21 02:54:30+00:002013-10-21 02:54:30updated113zaki007zaki0072013-10-21 02:11:44+00:002013-10-21 02:11:44updated112edit 5: added clarifying remarks to paragraphjlri228jlri2282013-10-21 01:21:06+00:002013-10-21 01:21:06updated111Edit4:added section on Darkling Beetles jlri228jlri2282013-10-21 01:19:21+00:002013-10-21 01:19:21updated110edit 3:having issues getting the edits to save... maybe someone is undoing them? But I reorder and color coded the pagejlri228jlri2282013-10-21 00:53:54+00:002013-10-21 00:53:54updated109edit 2: changes to page layout and reordered the sections of page... jlri228jlri2282013-10-21 00:51:06+00:002013-10-21 00:51:06updated108proofreadingbscurrybscurry2013-10-21 00:51:06+00:002013-10-21 00:51:06updated107edit 1: major organizational changes to title, flow and order of contentjlri228jlri2282013-10-21 00:43:28+00:002013-10-21 00:43:28updated106mayabasumayabasu2013-10-21 00:38:36+00:002013-10-21 00:38:36updated105Added article about human sexual selectionjkabacijkabaci2013-10-20 23:49:22+00:002013-10-20 23:49:22updated104jkabacijkabaci2013-10-20 23:48:55+00:002013-10-20 23:48:55updated103tgetztgetz2013-10-20 23:21:16+00:002013-10-20 23:21:16updated102typo, article additionkkogantikkoganti2013-10-20 22:10:46+00:002013-10-20 22:10:46updated101rachel08rachel082013-10-20 21:37:20+00:002013-10-20 21:37:20updated100rachel08rachel082013-10-20 21:36:35+00:002013-10-20 21:36:35updated99added budding hydra photohaliejhaliej2013-10-18 18:18:38+00:002013-10-18 18:18:38updated98rewording and grammarhaliejhaliej2013-10-18 18:16:37+00:002013-10-18 18:16:37updated97chersh93chersh932013-10-18 16:19:29+00:002013-10-18 16:19:29updated96gloriaszgloriasz2013-10-18 13:16:41+00:002013-10-18 13:16:41updated95gloriaszgloriasz2013-10-18 13:15:17+00:002013-10-18 13:15:17updated94gloriaszgloriasz2013-10-18 13:15:03+00:002013-10-18 13:15:03updated93tcard4tcard42013-10-18 02:58:18+00:002013-10-18 02:58:18updated92tbrownetbrowne2013-10-17 20:33:56+00:002013-10-17 20:33:56updated91eyang13eyang132013-10-17 01:26:09+00:002013-10-17 01:26:09updated90abutchabutch2013-10-16 21:34:28+00:002013-10-16 21:34:28updated89najjar22najjar222013-10-16 19:24:58+00:002013-10-16 19:24:58updated88mendyhmendyh2013-10-15 01:29:57+00:002013-10-15 01:29:57updated87henkhenk2013-10-14 19:09:35+00:002013-10-14 19:09:35updated86Nicole Hill- Sexual Selection nhill19nhill192013-10-14 15:52:29+00:002013-10-14 15:52:29updated85karlin14karlin142013-10-14 15:33:23+00:002013-10-14 15:33:23updated84add video of praying mantisduggan91duggan912013-10-14 14:42:34+00:002013-10-14 14:42:34updated83tbrownetbrowne2013-10-14 04:53:36+00:002013-10-14 04:53:36updated82I took out bullet points in two sections and made them into paragraphswtownewtowne2013-10-14 03:50:38+00:002013-10-14 03:50:38updated81jnunez26jnunez262013-10-14 03:47:53+00:002013-10-14 03:47:53updated80added explanation of behavioral intersexual selectionjnunez26jnunez262013-10-14 03:42:14+00:002013-10-14 03:42:14updated79enanovenanov2013-10-14 03:34:16+00:002013-10-14 03:34:16updated78glynchglynch2013-10-14 03:08:05+00:002013-10-14 03:08:05updated77mreutermreuter2013-10-13 15:20:02+00:002013-10-13 15:20:02updated76tabedintabedin2013-10-13 01:33:19+00:002013-10-13 01:33:19updated75gloriaszgloriasz2013-10-12 13:06:48+00:002013-10-12 13:06:48updated74gloriaszgloriasz2013-10-12 13:06:23+00:002013-10-12 13:06:23updated73sydneyb9sydneyb92013-10-10 20:12:10+00:002013-10-10 20:12:10updated72reemap26reemap262013-10-10 20:11:30+00:002013-10-10 20:11:30updated71sydneyb9sydneyb92013-10-10 20:11:17+00:002013-10-10 20:11:17updated70eyang13eyang132013-10-10 14:46:22+00:002013-10-10 14:46:22updated69tcard4tcard42013-10-09 17:55:08+00:002013-10-09 17:55:08updated68leeshahkimLeeshah Kim2013-10-09 12:32:11+00:002013-10-09 12:32:11updated67leeshahkimLeeshah Kim2013-10-09 12:30:49+00:002013-10-09 12:30:49updated66achenachen2013-10-09 04:20:44+00:002013-10-09 04:20:44updated65kristy7kristy72013-10-09 00:27:36+00:002013-10-09 00:27:36updated64kristy7kristy72013-10-09 00:26:41+00:002013-10-09 00:26:41updated63ahakimahakim2013-10-07 03:40:11+00:002013-10-07 03:40:11updated62abarton6abarton62013-10-07 02:19:58+00:002013-10-07 02:19:58updated61edwards9edwards92013-10-07 02:16:24+00:002013-10-07 02:16:24updated60Sexual Coercion linkbennywbennyw2013-10-07 01:04:26+00:002013-10-07 01:04:26updated59Added link and formatting for Traumatic Inseminationbennywbennyw2013-10-07 01:02:54+00:002013-10-07 01:02:54updated58Grammatical errors under selective selection and added bullets to intrasexual selection instead of dashes to match selective selection layout.jnunez26jnunez262013-10-07 00:57:35+00:002013-10-07 00:57:35updated57nikra91nikra912013-10-06 23:55:35+00:002013-10-06 23:55:35updated56Rearranged and made small word revisionslauren91lauren912013-10-06 23:50:04+00:002013-10-06 23:50:04updated55kde04kde042013-10-06 19:44:05+00:002013-10-06 19:44:05updated54xjwork17xjwork172013-10-06 18:49:35+00:002013-10-06 18:49:35updated53Added the link at the bottom describing sexual selection in ducksmanikmanik2013-10-06 18:03:03+00:002013-10-06 18:03:03updated52mbelyakombelyako2013-10-06 01:56:41+00:002013-10-06 01:56:41updated51tvashitvashi2013-10-05 15:04:51+00:002013-10-05 15:04:51updated50samponssampons2013-10-05 06:10:31+00:002013-10-05 06:10:31updated49shree7shree72013-10-04 20:55:34+00:002013-10-04 20:55:34updated48kehoekkehoek2013-10-04 20:51:04+00:002013-10-04 20:51:04updated47ybonillaybonilla2013-10-04 19:52:22+00:002013-10-04 19:52:22updated46gloriaszgloriasz2013-10-04 15:45:14+00:002013-10-04 15:45:14updated45gloriaszgloriasz2013-10-04 15:40:30+00:002013-10-04 15:40:30updated44Organizationddphanddphan2013-10-03 15:13:06+00:002013-10-03 15:13:06updated43Added tag - hotachenachen2013-10-03 15:13:03+00:002013-10-03 15:13:03addTag42achenachen2013-10-02 20:33:06+00:002013-10-02 20:33:06updated41melissa4melissa42013-09-28 07:23:36+00:002013-09-28 07:23:36updated40Added tag - sexual selectionahakimahakim2013-09-26 21:00:24+00:002013-09-26 21:00:24addTag39Removed tag - intersexualahakimahakim2013-09-26 21:00:10+00:002013-09-26 21:00:10removeTag38Added tag - lek matingahakimahakim2013-09-26 20:58:29+00:002013-09-26 20:58:29addTag37Added tag - mating systemsahakimahakim2013-09-26 20:58:15+00:002013-09-26 20:58:15addTag36Added tag - sexual conflictahakimahakim2013-09-26 20:58:03+00:002013-09-26 20:58:03addTag35Added tag - intersexualahakimahakim2013-09-26 20:57:46+00:002013-09-26 20:57:46addTag34Added tag - reproductionahakimahakim2013-09-26 20:57:35+00:002013-09-26 20:57:35addTag33ahakimahakim2013-09-26 20:54:12+00:002013-09-26 20:54:12updated32Added new section on Leksmbelyakombelyako2013-09-26 01:28:39+00:002013-09-26 01:28:39updated31kevinmkkevinmk2013-09-23 13:10:19+00:002013-09-23 13:10:19updated30ebythekkebythekk2013-09-23 00:40:08+00:002013-09-23 00:40:08updated29csharmacsharma2013-09-19 20:26:51+00:002013-09-19 20:26:51updated28mbelyakombelyako2013-09-19 17:21:52+00:002013-09-19 17:21:52updated27mbelyakombelyako2013-09-19 17:18:57+00:002013-09-19 17:18:57updated26Added a new section: reproductive strategiesmbelyakombelyako2013-09-19 17:18:40+00:002013-09-19 17:18:40updated25Added more information on the benefits of asexual reproduction and sexual reproductionmbelyakombelyako2013-09-19 17:11:36+00:002013-09-19 17:11:36updated24ekeatingekeating2013-09-17 20:04:20+00:002013-09-17 20:04:20updated23Added tag - selectionearly312early3122013-09-17 15:05:43+00:002013-09-17 15:05:43addTag22early312early3122013-09-16 16:25:50+00:002013-09-16 16:25:50updated21henkhenk2013-09-16 14:56:31+00:002013-09-16 14:56:31updated20kdv11kdv112013-09-16 12:56:55+00:002013-09-16 12:56:55updated19dragonfly example addedduggan91duggan912013-09-16 05:26:47+00:002013-09-16 05:26:47updated18skanman3skanman32013-09-15 21:27:08+00:002013-09-15 21:27:08updated17rwstrongrwstrong2013-09-15 21:07:40+00:002013-09-15 21:07:40updated16smarte18smarte182013-09-15 21:05:21+00:002013-09-15 21:05:21updated15smarte18smarte182013-09-15 20:55:26+00:002013-09-15 20:55:26updated14corrected spelling and formatted pagejlri228jlri2282013-09-15 20:45:08+00:002013-09-15 20:45:08updated13jlri228jlri2282013-09-15 20:43:20+00:002013-09-15 20:43:20updated12For my second post for the week, I outlined a few types of sexual conflict and embedded youtube videos to explain the corresponding types of sexual conflict jlri228jlri2282013-09-15 20:41:56+00:002013-09-15 20:41:56updated11jlri228jlri2282013-09-15 20:25:03+00:002013-09-15 20:25:03updated10added links to outside sources to further explain sexual conflict jlri228jlri2282013-09-15 20:24:31+00:002013-09-15 20:24:31updated9added a paragraph on sexual conflictjlri228jlri2282013-09-15 20:21:03+00:002013-09-15 20:21:03updated8Added a few words in sexual reproduction to make sense pkyungpkyung2013-09-15 03:53:42+00:002013-09-15 03:53:42updated7Introduced topic of comparing sexual to asexual selectionmbelyakombelyako2013-09-15 03:30:30+00:002013-09-15 03:30:30updated6asian108asian1082013-09-14 03:29:23+00:002013-09-14 03:29:23updated5kevinmkkevinmk2013-09-14 02:04:59+00:002013-09-14 02:04:59updated4bjenk07bjenk072013-09-14 02:02:49+00:002013-09-14 02:02:49updated3naa92naa922013-09-14 01:17:00+00:002013-09-14 01:17:00updated2First creatednaa92naa922013-09-14 01:12:48+00:002013-09-14 01:12:48created1wiki2013-11-25T03:26:27+00:00groups/evol3000/wiki/543e6FalseSexual Selection/Conflict/groups/evol3000/wiki/543e6/Sexual_SelectionConflict.htmlmayabasu224 updatesSexual Selection/Conflict Sexual selection is a mode of selection that operates on an organism's ability to obtain a mate. Sexual selection allows some individuals to out com...Falsemayabasu2013-11-25T03:26:27+00:00Repairing bad index entrymayabasumayabasu2018-02-22 14:26:55+00:002018-02-22 14:26:55updated148Repairing bad index entrymayabasumayabasu2018-02-22 14:26:53+00:002018-02-22 14:26:53updated147Repairing bad index entrymayabasumayabasu2018-02-21 16:23:56+00:002018-02-21 16:23:56updated146Repairing bad index entrymayabasumayabasu2018-02-21 16:23:55+00:002018-02-21 16:23:55updated145Repairing bad index entrymayabasumayabasu2015-01-22 13:55:44+00:002015-01-22 13:55:44updated144Repairing bad index entrymayabasumayabasu2015-01-22 13:28:23+00:002015-01-22 13:28:23updated143mayabasumayabasu2013-11-25 03:23:57+00:002013-11-25 03:23:57updated142Linked "slot limits"rbaskin1rbaskin12013-11-25 03:19:05+00:002013-11-25 03:19:05updated141grammar/syntax and a linkrbaskin1rbaskin12013-11-25 03:16:06+00:002013-11-25 03:16:06updated140Linked hip displacia in caninesrbaskin1rbaskin12013-11-25 03:12:24+00:002013-11-25 03:12:24updated139Added tag - domesticated animalsrachel08rachel082013-11-25 03:09:53+00:002013-11-25 03:09:53addTag138rachel08rachel082013-11-25 02:56:50+00:002013-11-25 02:56:50updated137rachel08rachel082013-11-25 02:53:13+00:002013-11-25 02:53:13updated136eyang13eyang132013-11-22 18:06:03+00:002013-11-22 18:06:03updated135xjwork17xjwork172013-11-21 23:51:06+00:002013-11-21 23:51:06updated134sydneyb9sydneyb92013-11-21 22:26:31+00:002013-11-21 22:26:31updated133improving contentbscurrybscurry2013-11-21 05:40:28+00:002013-11-21 05:40:28updated132xjwork17xjwork172013-11-14 22:08:51+00:002013-11-14 22:08:51updated131tbrownetbrowne2013-11-14 17:23:39+00:002013-11-14 17:23:39updated130dmwilsondmwilson2013-11-14 17:17:14+00:002013-11-14 17:17:14updated129tcard4tcard42013-11-14 03:18:52+00:002013-11-14 03:18:52updated128bjenk07bjenk072013-11-14 02:14:57+00:002013-11-14 02:14:57updated127dmwilsondmwilson2013-11-13 18:53:43+00:002013-11-13 18:53:43updated126tvashitvashi2013-11-13 16:12:56+00:002013-11-13 16:12:56updated125added a pictureksuf615ksuf6152013-11-12 16:14:10+00:002013-11-12 16:14:10updated124lgcarterlgcarter2013-11-12 15:44:28+00:002013-11-12 15:44:28updated123mbrdgmnmbrdgmn2013-11-10 23:25:59+00:002013-11-10 23:25:59updated122xjwork17xjwork172013-11-10 22:40:45+00:002013-11-10 22:40:45updated121samponssampons2013-11-10 22:36:35+00:002013-11-10 22:36:35updated120rachel08rachel082013-11-10 22:32:31+00:002013-11-10 22:32:31updated119re320re3202013-11-10 01:52:26+00:002013-11-10 01:52:26updated118edawg16edawg162013-11-09 23:21:00+00:002013-11-09 23:21:00updated117changed format of text to make information easier to read and interpretedawg16edawg162013-11-09 23:20:27+00:002013-11-09 23:20:27updated116deerandeeran2013-11-09 03:52:40+00:002013-11-09 03:52:40updated115improved wordingbscurrybscurry2013-11-07 23:32:57+00:002013-11-07 23:32:57updated114achenachen2013-11-04 15:54:03+00:002013-11-04 15:54:03updated113ashleyjwashleyjw2013-11-04 04:24:53+00:002013-11-04 04:24:53updated112abarton6abarton62013-11-04 00:00:40+00:002013-11-04 00:00:40updated111alomasalomas2013-11-03 23:41:15+00:002013-11-03 23:41:15updated110kdsouza9kdsouza92013-11-03 23:35:06+00:002013-11-03 23:35:06updated109tvashitvashi2013-11-03 19:17:24+00:002013-11-03 19:17:24updated108achenachen2013-11-01 22:23:27+00:002013-11-01 22:23:27updated107gloriaszgloriasz2013-11-01 02:12:10+00:002013-11-01 02:12:10updated106liishiiliishii2013-11-01 02:02:40+00:002013-11-01 02:02:40updated105liishiiliishii2013-11-01 02:02:37+00:002013-11-01 02:02:37updated104naa92naa922013-10-31 16:46:04+00:002013-10-31 16:46:04updated103mpattmpatt2013-10-31 15:29:45+00:002013-10-31 15:29:45updated102ybonillaybonilla2013-10-31 13:38:40+00:002013-10-31 13:38:40updated101ybonillaybonilla2013-10-31 13:37:04+00:002013-10-31 13:37:04updated100kde04kde042013-10-31 10:45:54+00:002013-10-31 10:45:54updated99kde04kde042013-10-31 10:43:23+00:002013-10-31 10:43:23updated98tabedintabedin2013-10-27 21:51:03+00:002013-10-27 21:51:03updated97dmdauerdmdauer2013-10-21 03:01:21+00:002013-10-21 03:01:21updated96grammarjsafkojsafko2013-10-21 02:58:41+00:002013-10-21 02:58:41updated95edwards9edwards92013-10-21 02:01:36+00:002013-10-21 02:01:36updated94kehoekkehoek2013-10-11 23:24:21+00:002013-10-11 23:24:21updated93casef10casef102013-10-11 22:44:37+00:002013-10-11 22:44:37updated92leeshahkimLeeshah Kim2013-10-11 14:54:41+00:002013-10-11 14:54:41updated91gloriaszgloriasz2013-10-11 14:49:27+00:002013-10-11 14:49:27updated90gloriaszgloriasz2013-10-11 14:47:01+00:002013-10-11 14:47:01updated89added information on farm animals sectionmbelyakombelyako2013-10-10 18:18:28+00:002013-10-10 18:18:28updated88Organization of headersddphanddphan2013-10-10 15:12:14+00:002013-10-10 15:12:14updated87formattingmia2016mia20162013-10-09 17:26:10+00:002013-10-09 17:26:10updated86snoccersnoccer2013-10-09 14:23:28+00:002013-10-09 14:23:28updated85writer44writer442013-10-09 02:43:09+00:002013-10-09 02:43:09updated84cslidecslide2013-10-07 03:06:22+00:002013-10-07 03:06:22updated83nkamnkam2013-10-02 17:35:04+00:002013-10-02 17:35:04updated82nkamnkam2013-10-02 17:34:02+00:002013-10-02 17:34:02updated81nkamnkam2013-10-02 17:32:47+00:002013-10-02 17:32:47updated80made some formatting changesmia2016mia20162013-10-01 20:57:32+00:002013-10-01 20:57:32updated79lcaplanlcaplan2013-10-01 02:54:04+00:002013-10-01 02:54:04updated78kevinmkkevinmk2013-09-30 21:51:42+00:002013-09-30 21:51:42updated77bjenk07bjenk072013-09-30 21:51:19+00:002013-09-30 21:51:19updated76bjenk07bjenk072013-09-30 21:50:08+00:002013-09-30 21:50:08updated75bjenk07bjenk072013-09-30 21:37:01+00:002013-09-30 21:37:01updated74dogs ccranccran2013-09-30 06:47:11+00:002013-09-30 06:47:11updated73added under food sectionginasanginasan2013-09-30 02:49:36+00:002013-09-30 02:49:36updated72cslidecslide2013-09-30 02:04:52+00:002013-09-30 02:04:52updated71grammatical changes jlri228jlri2282013-09-30 01:23:25+00:002013-09-30 01:23:25updated70ybonillaybonilla2013-09-29 23:27:17+00:002013-09-29 23:27:17updated69ybonillaybonilla2013-09-29 23:26:30+00:002013-09-29 23:26:30updated68ybonillaybonilla2013-09-29 23:24:52+00:002013-09-29 23:24:52updated67added info about killer beesbscurrybscurry2013-09-29 19:26:11+00:002013-09-29 19:26:11updated66fgkatzfgkatz2013-09-29 15:09:03+00:002013-09-29 15:09:03updated65kkogantikkoganti2013-09-29 02:17:35+00:002013-09-29 02:17:35updated64shree7shree72013-09-28 22:59:28+00:002013-09-28 22:59:28updated63alomasalomas2013-09-28 01:16:23+00:002013-09-28 01:16:23updated62gloriaszgloriasz2013-09-27 12:14:14+00:002013-09-27 12:14:14updated61added cat photo and bit about hypoallergenic and hairless specieshaliejhaliej2013-09-27 03:32:40+00:002013-09-27 03:32:40updated60edited/ cut/ rephrased *** section about dog inbreedinghaliejhaliej2013-09-27 03:20:10+00:002013-09-27 03:20:10updated59kristy7kristy72013-09-26 23:36:25+00:002013-09-26 23:36:25updated58gloriaszgloriasz2013-09-26 20:51:22+00:002013-09-26 20:51:22updated57rtalleyrtalley2013-09-26 15:57:14+00:002013-09-26 15:57:14updated56Added Examples from classddphanddphan2013-09-26 15:13:29+00:002013-09-26 15:13:29updated55added to dog sectiontcard4tcard42013-09-26 00:44:23+00:002013-09-26 00:44:23updated54achenachen2013-09-26 00:34:28+00:002013-09-26 00:34:28updated53reorganized a little bitlauren91lauren912013-09-24 17:23:33+00:002013-09-24 17:23:33updated52bpcroftbpcroft2013-09-24 13:28:11+00:002013-09-24 13:28:11updated51rwstrongrwstrong2013-09-24 03:19:39+00:002013-09-24 03:19:39updated50rwstrongrwstrong2013-09-24 03:02:24+00:002013-09-24 03:02:24updated49achenachen2013-09-23 22:11:53+00:002013-09-23 22:11:53updated48leeshahkimLeeshah Kim2013-09-23 22:08:58+00:002013-09-23 22:08:58updated47talathitalathi2013-09-23 20:51:07+00:002013-09-23 20:51:07updated46added detail to breeders equationduggan91duggan912013-09-23 15:00:22+00:002013-09-23 15:00:22updated45added link to bbc documentary on selective breeding in dogs jlri228jlri2282013-09-22 23:37:20+00:002013-09-22 23:37:20updated44sgamachesgamache2013-09-22 15:29:06+00:002013-09-22 15:29:06updated43grammarspenc90spenc902013-09-22 15:19:21+00:002013-09-22 15:19:21updated42sgamachesgamache2013-09-22 15:16:21+00:002013-09-22 15:16:21updated41kkogantikkoganti2013-09-22 03:35:05+00:002013-09-22 03:35:05updated40kkogantikkoganti2013-09-22 03:34:06+00:002013-09-22 03:34:06updated39Clarified that before genes were known about farmers still knew that some beneficial traits would be passed on to offspring. Saying that farmers intentionally bred cattle for traits but "unintentially utilized heretiablity" doesn't make senseadwomackadwomack2013-09-22 02:51:33+00:002013-09-22 02:51:33updated38general polishing and added additional informationbscurrybscurry2013-09-22 00:59:56+00:002013-09-22 00:59:56updated37asian108asian1082013-09-21 01:40:14+00:002013-09-21 01:40:14updated36kehoekkehoek2013-09-20 20:49:41+00:002013-09-20 20:49:41updated35added article link about Uga and description from the NY timeshaliejhaliej2013-09-20 20:09:00+00:002013-09-20 20:09:00updated34added bulldog transformation imagehaliejhaliej2013-09-20 20:05:10+00:002013-09-20 20:05:10updated33shaque3shaque32013-09-20 16:31:33+00:002013-09-20 16:31:33updated32alomasalomas2013-09-20 16:04:50+00:002013-09-20 16:04:50updated31henkhenk2013-09-20 14:43:48+00:002013-09-20 14:43:48updated30edited disease heterogeneity, added fox domestication studylauren91lauren912013-09-20 03:32:15+00:002013-09-20 03:32:15updated29kristy7kristy72013-09-20 02:44:56+00:002013-09-20 02:44:56updated28bevinbbevinb2013-09-20 01:15:42+00:002013-09-20 01:15:42updated27gloriaszgloriasz2013-09-20 00:34:06+00:002013-09-20 00:34:06updated26Added to FOODccranccran2013-09-19 21:08:37+00:002013-09-19 21:08:37updated25csharmacsharma2013-09-19 20:28:52+00:002013-09-19 20:28:52updated24added examplespjung24pjung242013-09-19 17:04:39+00:002013-09-19 17:04:39updated23bpcroftbpcroft2013-09-19 15:27:36+00:002013-09-19 15:27:36updated22karlin14karlin142013-09-19 15:16:14+00:002013-09-19 15:16:14updated21karlin14karlin142013-09-19 15:15:06+00:002013-09-19 15:15:06updated20Added Breeder's equationddphanddphan2013-09-19 15:07:05+00:002013-09-19 15:07:05updated19karlin14karlin142013-09-19 15:06:11+00:002013-09-19 15:06:11updated18kncox14kncox142013-09-19 14:23:30+00:002013-09-19 14:23:30updated17eyang13eyang132013-09-19 14:07:15+00:002013-09-19 14:07:15updated16eyang13eyang132013-09-19 13:59:54+00:002013-09-19 13:59:54updated15cass16cass162013-09-18 15:15:30+00:002013-09-18 15:15:30updated14mayabasumayabasu2013-09-18 14:59:37+00:002013-09-18 14:59:37updated13mendyhmendyh2013-09-18 14:33:25+00:002013-09-18 14:33:25updated12added bulldog stuff and fun fact about dog phenotypeslauren91lauren912013-09-18 03:10:55+00:002013-09-18 03:10:55updated11ekeatingekeating2013-09-17 20:00:37+00:002013-09-17 20:00:37updated10added a factmia2016mia20162013-09-17 19:30:50+00:002013-09-17 19:30:50updated9mia2016mia20162013-09-17 19:28:11+00:002013-09-17 19:28:11updated8artificial selection in dogsmattbossmattboss2013-09-17 15:12:03+00:002013-09-17 15:12:03updated7Added tag - selectionddphanddphan2013-09-17 15:06:02+00:002013-09-17 15:06:02addTag6Created Pageddphanddphan2013-09-17 15:02:53+00:002013-09-17 15:02:53updated5Added tag - artificial selectionddphanddphan2013-09-17 14:55:15+00:002013-09-17 14:55:15addTag4Added tag - selective breedingddphanddphan2013-09-17 14:55:09+00:002013-09-17 14:55:09addTag3Added tag - hotddphanddphan2013-09-17 14:55:04+00:002013-09-17 14:55:04addTag2First createdddphanddphan2013-09-17 14:55:00+00:002013-09-17 14:55:00created1wiki2013-11-25T03:23:57+00:00groups/evol3000/wiki/ce8b9FalseSelective Breeding or Artificial Selection/groups/evol3000/wiki/ce8b9/Selective_Breeding_or_Artificial_Selection.htmlmayabasu148 updatesSelective Breeding or Artificial Selection Artificial Selection is a form of selection in which humans actively choose which traits should be passed onto offspring. Humans have used selec...Falsemayabasu2013-11-25T03:23:57+00:00edit 9: formatting to the page... " articles, videos and diagrams section .. also added video about richard dawkinsjlri228jlri2282013-11-24 22:30:49+00:002013-11-24 22:30:49updated27added articlekkogantikkoganti2013-11-24 18:41:25+00:002013-11-24 18:41:25updated26grammarjsafkojsafko2013-10-27 21:18:58+00:002013-10-27 21:18:58updated25jnguyen1jnguyen12013-10-26 04:24:43+00:002013-10-26 04:24:43updated24jnguyen1jnguyen12013-10-26 04:23:32+00:002013-10-26 04:23:32updated23kehoekkehoek2013-10-25 19:56:42+00:002013-10-25 19:56:42updated22achenachen2013-10-24 21:34:03+00:002013-10-24 21:34:03updated21rewording and grammarhaliejhaliej2013-10-24 19:17:33+00:002013-10-24 19:17:33updated20grammar to parasite manipulate paragraphhaliejhaliej2013-10-24 19:16:59+00:002013-10-24 19:16:59updated19kristy7kristy72013-10-24 03:11:46+00:002013-10-24 03:11:46updated18Removed tag - phenotypeksuf615ksuf6152013-10-23 17:57:20+00:002013-10-23 17:57:20removeTag17Added tag - richard dawkinsksuf615ksuf6152013-10-23 17:57:09+00:002013-10-23 17:57:09addTag16Removed tag - dawkinsksuf615ksuf6152013-10-23 17:57:01+00:002013-10-23 17:57:01removeTag15added tags to pageksuf615ksuf6152013-10-22 15:20:17+00:002013-10-22 15:20:17updated14Added tag - dawkinsddphanddphan2013-10-22 15:20:06+00:002013-10-22 15:20:06addTag13Added tag - extended phenotypeddphanddphan2013-10-22 15:19:52+00:002013-10-22 15:19:52addTag12Organizationddphanddphan2013-10-22 15:04:17+00:002013-10-22 15:04:17updated11mayabasumayabasu2013-10-21 00:37:10+00:002013-10-21 00:37:10updated10typos, elaborationkkogantikkoganti2013-10-20 21:11:02+00:002013-10-20 21:11:02updated9added the 2nd and 3rd examples of EP described by Dawkinsjnunez26jnunez262013-10-20 18:20:05+00:002013-10-20 18:20:05updated8minor adjustments to 1st example of EPjnunez26jnunez262013-10-20 18:00:57+00:002013-10-20 18:00:57updated7added a pic of Dawkin's book and 1st example of EP that he describesjnunez26jnunez262013-10-20 17:55:12+00:002013-10-20 17:55:12updated6alomasalomas2013-10-20 14:19:09+00:002013-10-20 14:19:09updated5Created Pageddphanddphan2013-10-19 19:29:00+00:002013-10-19 19:29:00updated4Added tag - hotddphanddphan2013-10-19 19:28:59+00:002013-10-19 19:28:59addTag3Added tag - phenotypeddphanddphan2013-10-19 19:28:58+00:002013-10-19 19:28:58addTag2First createdddphanddphan2013-10-19 19:23:37+00:002013-10-19 19:23:37created1wiki2013-11-24T22:30:49+00:00groups/evol3000/wiki/94a1aFalseExtended Phenotype/groups/evol3000/wiki/94a1a/Extended_Phenotype.htmljlri22827 updatesExtended Phenotype An extended phenotype includes all of the traits that an organism has that can influence its fitness; the extended phenotype can include structures t...Falsejlri2282013-11-24T22:30:49+00:00hot/groups/evol3000/search/index.rss?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomelist/groups/evol3000/search/?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcomeRecent ChangesRecentChangesListUpdates?sort=modifiedDate&kind=all&sortDirection=reverse&excludePages=wiki/welcome0/groups/evol3000/sidebar/RecentChangesListmodifiedDateallRecent ChangesRecentChangesListUpdateswiki/welcomeNo recent changes.reverse5searchlist/groups/evol3000/calendar/Upcoming EventsUpcomingEventsListEvents1Getting events...

# data[].attributes.attachment_link.title
Selective Breeding or Artificial Selection

# data[].attributes.attachment_link.description
Artificial Selection is a form of selection in which humans actively choose which traits should be passed onto offspring. Humans have used selective breeding long before Darwin's Postulates and the discovery of genetics.