CMMB 403 Lecture Notes - Lecture 25: Homeobox, Collinearity, Chromosome
4 Jan 2019
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The 39 hox genes in the mammalian (and avian) genome. Organized into 4 clusters (a, b, c, d) Clusters are found on separate chromosomes nowhere near each other. Hoxc1 was most probably lost during evolution. Paralogs: genes related by duplication within a genome. Hoxa1 and hoxb1 are paralogs, but hoxa1 and hoxa13 are not. Can tell if a gene is a paralogue if they have the same number. Paralog: gene in same species, but there are different versions of the gene. Small number of gene (eg. hoxa1) = expressed more anteriorly. The most anterior region where a hox gene is expressed is usually where its pattering function is most important. Homeobox: a dna sequence the codes for a protein domain called a homeodomain. Therefore, homeobox genes code for homeodomain-containing transcription factor proteins. Genes thought to have originated from ancestral cluster, that was thought to be duplicated twice, so you get 4 clusters.
