Meeting Abstract
Homeobox transcription factors control body patterning across the diverse array of bilaterian body plans. As sister group to the Bilateria, Cnidaria provides an important evolutionary framework for understanding the evolution of body plans and the genes that pattern them. Hox and ParaHox gene homologues have been identified in the hydrozoan Hydra and in the anthozoans Nematostella vectensis and Acropora digitifera. The complete gut of bilaterians defines the anterior-posterior axis patterned by Hox and ParaHox genes, but how do these genes pattern a body that lacks anterior-posterior directionality? Hox genes have been shown to pattern the oral-aboral axis in the polyp form of hydrozoans and anthozoans, but their role is still unclear in the scyphozoan transition from polyp to medusa body plan, a process known as strobilation. Scyphozoan polyps may also bud off football-shaped propagules, which swim using cilia along the oral-aboral axis, similar to planulae, and metamorphose into new polyps. Strobilation and propagule-budding may even occur simultaneously in the same polyp. Here we investigate Hox genes in the upside-down jellyfish Cassiopea xamachana. Starting with adult, sexually mature medusae, our lab has facilitated settlement of planulae, strobilation of polyps, and growth of ephyrae into medusae, allowing investigation of Hox expression in all life stages and body forms of the animal.
