HMB265H1 Chapter Notes - Chapter 20: Pleiotropy, Cell Surface Receptor, Arthropod Eye
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HMB265H1 Full Course Notes
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Not all genes turned on in all tissues. Cells regulate expression of genes so each gene"s protein product appears only when and where it"s needed. Easier to identify genes whose mutant alleles have phenotypic effects on development. Cells of all eukaryotic organisms have common structural features (nucleus + mitochondria) Ex: eyes of insects + vertebrates evolved from same pathway. If nematode loses 1 cell, can"t develop b/c both cells already differentiated. If human embryo loses 1 cell, will get identical twins b/c human embryo can regulate fates according to their environment. Examine mutant organisms, identify rare individuals w/ phenotype of interest. Ex: find all the individuals w/ bad eyes. Genetic screens identify genes required for specific developmental processes. Molecular mechanisms that guide development of fruit fly compound eye. Each one made of small number of cells that assemble in same order every time. If have defect will be iterated 800 times in each eye = easy to see mutant.