Meeting Abstract
The endoderm, through extensive anterior–posterior (AP) patterning, gives rise to an array of specialized cell types and organs. This regionalization is the result of transcription factors and other signaling molecules being expressed in a highly regulated spatial–temporal manner. While this process has been well characterized in mammals, the same cannot be said for other vertebrates. Here we present a developmental series of the endoderm and its derivatives in the little skate (Leucoraja erinacea) and zebrafish (Danio rerio ). We report expression of genes known to be involved in mammalian gut regionalization to test the hypotheses of their conserved function across jawed vertebrates. We then focus on the development of the unique “spiral valve” structure of the little skate intestine. The unique spiral valve structure may play a role in the ability of chondrichthyans to colonize new niches. Furthermore, understanding how these unique structures develop can help us better understand major developmental changes, for example those that might have occurred in the water-to-land transition of vertebrates.
