What are homeobox genes? How do patterns in the evolution of these genes show shared ancestry among all animals? How do the patterns show divergence? As you know, arthropods possess a variety of different mouth parts; since homeobox genes control the development of the head region, scientists have argued that they were instrumental in driving the diversification of arthropods. Imagine a single group of arthropods with the same mouth parts and explain the steps that might have followed to give rise to the diversity we see today.