CSB328H1 Lecture Notes - Lecture 19: Hox Gene, Gene Duplication, Bilateria
28 Aug 2019
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Lecture 19: hox genes: homeotic genes are conductors of complex gene programs. Each homeotic gene orchestrates its own gene program. Results in large diversity of the body plan: homeotic genes conserved in both invertebrates and vertebrates. Homeotic/hox gene complex is conserved in animals: we have 4 hox gene classes in mammals. Homeotic genes in xenopus: dfd and abdb9 has homologous genes in all mammal hox gene clusters. Hox b most similar to homeostatic gene in drosophila (b3 not present drosophila) Abdb goes through divisions in mammals, many gene copies in mammals: segmental organization in vertebrate: Evolution of hox gene complex: trilobites had hox gene clusters (single ancestral hox gene) Ancestral bilaterian hox gene complex in them consisted of 7 genes. Although highly conserved gene cluster but changes occurring in the form duplications of particular hox genes: mammals have 4 hox gene clusters (38 genes) A duplication (2) second duplication in mammals (4: orthologs (scr-hoxa5)
