https://padlet.com/gweiss1/orc3m91p8ak86so1 Made with a bold sensibility en-us 2022-03-14 16:23:45 UTC 2022-03-14 16:39:56 UTC hello@padlet.com https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094226462 “In terms of our geography analogy, cells, tissues, and organs have a specific position on the globe of the embryo defined by their longitude, latitude, altitude (if projecting out from the body), and depth (within the layers of the body), as well as a “national” identity (nerve cells, liver cells, etc.)” ]]> 2022-03-14 16:26:51 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094226462 24liuo1_1 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228143 I have described the genetic tool kit for development and how its discovery was driven by the study of spectacular mutants that made the wrong number of body parts, or put a part in the wrong place..]]> 2022-03-14 16:27:47 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228143 24liuo1_1 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228886 Our tool kit genes are just pieces of our genetic material, a small fraction of the 13,700 genes in a fruit fly or the 25,000 genes of a mammal. Granted, we have identified many critical pieces…]]> 2022-03-14 16:28:08 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228886 23gardnerem2 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228909 “While the eggs of vertebrates differ greatly in size and character, from tiny mammal eggs to the enormous shelled eggs of large birds and reptiles, and the adult forms range from guppies to elephants and dinosaurs, all vertebrate embryos pass through a stage of development where they appear somewhat similar.” (Ch. 4, 98)]]> 2022-03-14 16:28:09 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094228909 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094229314 “Our tool kit genes are just pieces of our genetic material, a small fraction of the 13,700 genes in a fruit fly or the 25,000 genes of a mammal.” (Ch. 4, pg.83)]]> 2022-03-14 16:28:23 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094229314 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094230335 2022-03-14 16:28:55 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094230335 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094230731 “There is an orderly pace of somite formation, occurring about every twenty minutes in a zebrafish embryo, every hour and a half in a chicken embryo, and every two hours in a mouse embryo.” ]]> 2022-03-14 16:29:05 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094230731 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094233051 Frog and fly embryos are very vulnerable to predators. The sprint to complete development is a survival imperative and of the hundreds of eggs produced by a female, only a fraction will reach adulthood. Humans have a different ecology, and our development takes place in maximum security and unfolds, at least initially, at a much slower pace.]]> 2022-03-14 16:30:21 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094233051 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094233716 "He showed a picture of an intact embryo, then an embryo that had been put through a blender, and finally an embryo whose blended components had been centrifuged together" (Ch. 4, Page 83).]]> 2022-03-14 16:30:42 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094233716 23gardnerel2 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094234352 “Tool kit genes, stirred into action by fertilization, are starting to mark out the geography of the developing embryo. While all cells in the growing embryo contain the same DNA (and the same genes), the tool kit genes become active.”]]> 2022-03-14 16:30:55 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094234352 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094234906 “The beauty of the limb is also sculpted by death. The seperation of digits in mice, chicks, and humans is due to the death of the tissue between the digits in the developing limb. Within the padlike hands and feet, these interdigital zones are marked by the expression of different tool kit genes that instruct the cells in the zones to undergo programmed cell death” pg 103]]> 2022-03-14 16:31:11 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094234906 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094236160 "... so it takes about as long to make a 32- cell human embryo as to make a complete frog tadpole" (Ch. 4, Page 88).]]> 2022-03-14 16:31:47 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094236160 23mulderigd https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094236586 "By visualizing tool kit genes in action and embryos- the gene stripes I first saw that night in Colorado- we can see the position and shapes of structures long before they actually form. The images of tool kit genes in embryos create a vivid, dynamic map of the geography of a growing embryo" ]]> 2022-03-14 16:32:01 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094236586 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094240262 “For example, the expression of one tool kit gene marks the future forebrain and midbrain, while a second gene marks out the hindbrain and the midbrain/hindbrain boundary.”]]> 2022-03-14 16:33:59 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094240262 https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094240932 “Just as in the construction of a building, where there is an order to the sequence of steps . . . there is an order to building animals, from the making of the basic body plan to the fine detailing of individual body parts.”]]> 2022-03-14 16:34:16 UTC https://padlet.com/gweiss1/orc3m91p8ak86so1/wish/2094240932