AP BIOLOGY

Detailed explanation-1: -Hox genes are an evolutionary highly conserved gene family. They determine the anterior-posterior body axis in bilateral organisms and influence the developmental fate of cells.

Detailed explanation-2: -The role of the Hox genes is to specify positional identity in the embryo rather than the development of any specific structure. These positional values are interpreted differently in different embryos to influence how the cells in a region develop into, for example, segments and appendages.

Detailed explanation-3: -Hox genes code for proteins that attach to molecular switches on DNA, turning other genes on and off. The DNA-binding piece of a Hox protein is called the homeodomain, and it’s encoded by the homeobox. The homeodomains in different Hox proteins are similar but not identical-they bind to different DNA sequences.

Detailed explanation-4: -Hox genes are turned on in specific patterns by the protein products of the gap genes and pair-rule genes. Their expression patterns are refined-by the products of these genes and through interactions with other Hox proteins-as the embryo develops.