Most animals, including humans, display an obvious organization of specific body parts and organs along the anterior to posterior axis (A-P axis, head to toe for humans), and over the past several decades scientists have discovered a set of genes, known as homeotic genes, which control the placement of organs and appendages along the A-P axis. While these genes were first discovered in fruit flies, they were subsequently identified in all animals and found to play a common role in controlling the development of such varied species as flies, mice, humans, and worms. While the overall functions of these genes are well conserved, changes in where and when these genes are activated can create remarkable changes in body organization. The aim of this research is to understand the role that these genes have played in the evolutionary processes that have generated animal biodiversity. To do this, the investigators will focus on a group of animals that shows the greatest diversity in the organization of their appendages, the crustaceans, which include shrimp, crabs, lobsters, and an emerging model system called Parhyale. Using modern genetic approaches, the investigators will determine the specific roles of individual homeotic genes in Parhyale, and then use comparative methods to determine if changes in the patterns of homeotic gene expression are responsible for the differences between appendage organization in the various species. The research is expected to reveal the specific types of developmental and evolutionary changes that can be mediated by these genes. This research will train students in the laboratory and will be used to illustrate evolutionary principles to K-12 students and local community college students. Broader outreach to the general public will include public lectures and media presentations.
