BIO230H1 Lecture Notes - Lecture 9: Hox Gene, Hematopoietic Stem Cell Transplantation, Cellular Signalling
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BIO230H1 Full Course Notes
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Regulatory hierarchies: an extrinsic mechanism of cell differentiation. Related to the morphogens - similar, but happens again and again. Start with two populations of cells, morphogen acts on a to create c. C then induces a signal to create d and e cells from a and b. Can be the same morphogen, different effects due to different precursors. Results in same striping pattern seen in induction effects. Note that gene expression is what changes, not the inherent dna. These refine patterns of cell differentiation to create segmental patterns. Segments of body or developing embryo that repeat in a pattern. You change transcription patterns to get segmental patterns of gene expression. Stunted growth in larvae as segmentation can"t occur anymore. Segmentation is fundamental to body plans of animals, such as insects. Segmentation does not have to be exact - but it is very similar with some variation. Repeated patterns in other structures such as in the spine, the legs, etc.
