BIOL 103 Chapter Notes - Chapter 17: Morphogen, Gap Gene, Homeobox
11 Mar 2014
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Development in animals: oocyte is critical to establishing pattern of development that will produce an adult organism. Has anterior + posterior ends: blastoderm; developed from a zygote. Lots of nuclei scattered throughout yolk; eventually they migrate/line up along cell membrane: gastrulation: involves well-ordered rearrangement of cells in the embryo. Produces a gastrula: made of the layers ectoderm (outside), mesoderm (in between), endoderm (inside) and: embryo divided into segmented body pattern. Head, thorax, abdomen: larva: free-living organism that is morphologically very different from the adult, pupa: through metamorphosis, changes into a mature adult. Phase 1: maternal effect genes promote formation of main body axes. Maternal effect genes controls where morphogen concentrations are. Morphogen activates certain genes in certain regions of the embryo, depending on if it"s in high [ ] Morphogen activates genes in certain regions but not others; role in pattern formation + segregation. Segmentation genes: genes required for embryo to develop a segmented pattern.
