https://padlet.com/11301766/sqiyoxpju2rq By: Bryce Harris en-us 2018-03-30 18:33:14 UTC 2023-02-12 19:08:54 UTC hello@padlet.com 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/247539611 A small fruit fly, used extensively in genetic research because of its large chromosomes, numerous varieties, and rapid rate of reproduction.

]]> 2018-03-30 18:39:57 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/247539611 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/247539889

The fruit fly is the most extensively used and one of the most well understood of all the model organisms.

 Drosophila fruit flies measure approximately 3 mm in length.

Drosophila larvaeare small, white and glossy with a similar appearance to worms.

]]> 2018-03-30 18:42:35 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/247539889 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/247540555

Males have dark, rounded genitalia at the tip of their abdomen, whereas females have light, pointed genitalia.

 Male Drosophila are generally smaller than their female counterparts, and have a darker abdomen. The posterior segments of the Drosophila female are only pigmented in their posterior halves, whereas these segments are almost completely pigmented in the males. 

 The males also have a unique characteristic on their forelegs; the sex comb. The sex comb is a small patch of bristles visible on the forelegs of the male .

]]> 2018-03-30 18:49:11 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/247540555 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/247541218 At room temperature, fruit flies can develop into adults within one to two weeks. The egg and larval stages span approximately eight days, while the pupal stage lasts six days. The adult fruit fly lives for several weeks. Twenty-four hours after a female fruit fly lays her eggs, larvae hatch.]]> 2018-03-30 18:54:50 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/247541218 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/248603211 Fruit flies share nearly 60% of human genes and are studied by thousands of scientists around the world. The reason is that fruit flies and humans use the same or similar genes to develop into adults. And the short life cycle of the fly makes it an ideal subject for genetic experiments.]]> 2018-04-04 17:34:44 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/248603211 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249964368 Along DNA molecule which, for the largest chromosomein the fruit fly, Drosophila melanogaster, has a length of about 2.1 cm., or 62,000 kb [ref. 1; kb (kilo bases) is a unit of length equal to 1000 bases or base pairs in single-stranded or double- stranded nucleic acids].]]> 2018-04-09 18:03:41 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249964368 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249968589 In terms of the number of genes,, however, the comparison isn't nearly so lopsided: The fly has approximately 15,500 genes on its four chromosomes, whereas humanshave about 22,000 genes among their 23 chromosomes. Thus the density of genes per chromosome in Drosophila is higher than for the human genome.]]> 2018-04-09 18:09:57 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249968589 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249970299 Such a substitution could: change a codon to one that encodes a different amino acid and cause a small change in the protein produced. For example, sickle cell anemia is caused by a substitution in the beta-hemoglobin gene, which alters a single amino acid in the protein produced.]]> 2018-04-09 18:12:49 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249970299 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249974337 In contrast to DNA damage, a mutation is a change in the base sequence of the DNA. A mutation cannot be recognized by enzymes once the base change is present in both DNA strands, and thus a mutation cannot be repaired. At the cellular level, mutations can cause alterations in protein function and regulation.]]> 2018-04-09 18:20:24 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249974337 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249975570 Abstract. The isolation of chemically induced mutations in forward genetic screens is one of the hallmarks of Drosophila genetics. ... We present a strategy that allows mapping of lethal mutations, as well as viable mutations with visible phenotypes, with minimal resources.]]> 2018-04-09 18:22:40 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249975570 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249977683 Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
Meiosis is a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.]]> 2018-04-09 18:26:39 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249977683 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249979509 Mitosis produces diploid cells (46 chromosomes) whereas meiosis produces haploid cells (23 chromosomes). Mitosis produces two identical daughter cells whereas meiosis produces four genetically different daughter cells.]]> 2018-04-09 18:29:40 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249979509 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249980879 Mitosis produces diploid cells (46 chromosomes) whereas meiosis produces haploid cells (23 chromosomes). Mitosis produces two identical daughter cells whereas meiosis produces four genetically different daughter cells.
A comparison of a chiasmate meiosis (A) and the achiasmate meiosis of Drosophila males (B). ... In most organisms the synaptonemal complex, which connects paired chromosomes along their entire length, dissolves near the end of meiotic prophase (pachytene).]]> 2018-04-09 18:32:01 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249980879 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249981764 Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits.]]> 2018-04-09 18:33:37 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249981764 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249982301 Enetic variation means that biological systems – individuals and populations – are different over space. Each gene pool includes various alleles of genes. ... Genetic variation is brought about, fundamentally, by mutation, which is a permanent change in the chemical structure of chromosomes.]]> 2018-04-09 18:34:45 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249982301 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249983026 The principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors assort independentlyduring gamete production, giving different traits an equal opportunity of occurring together. Expand. Also called Mendel's second law, Mendel's law.]]> 2018-04-09 18:36:02 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249983026 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249984449 Learning about Genetics Using Flies. Model organisms are species that are studied to understand the biology of other organisms, often humans. Fruit flies share 75% of the genes that cause disease with humans, so scientists can learn about human genetics by studying fruit fly genetics.]]> 2018-04-09 18:38:45 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249984449 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/249985741 A heterozygous individual is someone who has two different alleles at a locus. For instance, using the sickle cell example, a heterozygous individual might have a genotype of AS. A homozygous individual has two identical alleles at a locus. The genotype for a homozygous individual might be AA or SS.]]> 2018-04-09 18:40:43 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/249985741 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250097153 Genotype versus phenotype. An organism's genotypeis the set of genes that it carries. An organism's phenotype is all of its observable characteristics — which are influenced both by its genotype and by the environment. ... For example, differences in the genotypes can produce different phenotypes.]]> 2018-04-10 02:41:10 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250097153 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250098478 Females are X/X and males are X/Y. Chromosome 4 is small and contains hardly any genes. Like most organisms, Drosophila have the annoying property that most genes are named after their loss-of-function phenotype, i.e. the opposite of what they do. For instance, the white gene makes eyes red.]]> 2018-04-10 02:51:08 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250098478 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250098972 That is, they describe how likely it is for a certain phenotype to pass from parent offspring. ... For arecessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent. An individual with one dominant and onerecessive allele for a gene will have the dominantphenotype.]]> 2018-04-10 02:54:00 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250098972 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250099618 Since the X-chromosome is bigger and contains more genes than the Y-chromosome, most sex-linked traits are X-linked traits. Wild-type fruit flies have dark red eyes, but there are recessive alleles of this eye color gene (called the white gene) that cause individuals to have white eyes.]]> 2018-04-10 02:58:13 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250099618 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250099988 Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.]]> 2018-04-10 03:00:49 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250099988 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250101647 The two alleles of a gene can also be co- dominant or one allele can have incomplete dominance over the other allele. Sometimes, a gene can have more than two alleles as in the case of multiple allele traits. ... However, some fruit flies have an abnormal trait.]]> 2018-04-10 03:13:57 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250101647 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250102354 This is why males exhibit some traits more frequently than females. In humans, red-green colorblindness is a recessive sex-linked trait. It is found on the X chromosome, not the Y. Because, males only have one X chromosome, they have a much greater chance of having red-green colorblindness.]]> 2018-04-10 03:18:50 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250102354 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250102832 Since the trait of white eye color is recessive and linked to sex, it shows its effect in the male because of single X-chromosome. The female flies can show white-eye trait when both its X-chromosome carry the recessive allele of the white eye.]]> 2018-04-10 03:22:12 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250102832 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250103276 A pedigree is ]]> 2018-04-10 03:25:24 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250103276 11301766 https://padlet.com/11301766/sqiyoxpju2rq/wish/250103413 This is a pedigree of my drosopila family.]]> 2018-04-10 03:26:25 UTC https://padlet.com/11301766/sqiyoxpju2rq/wish/250103413