Development and Evolution of Marine Invertebrates
Origins of body plan novelty during evolution
I am interested in the origins of body plan novelty during evolution. My lab approaches this problem by studying the cellular and molecular changes in the developmental program that lead to changes in the adult body plan. We focus on polychaete annelids, a group more commonly known as the segmented worms. We study multiple species with distinct life history characteristics and body plan morphologies to utilize the strengths of a comparative approach.
One focus of the lab has been to develop Capitella teleta, a polychaete annelid, as a developmental model for studies of body plan evolution within the lophotrochozoan superclade. Capitella teleta, known for years as Capitella sp. I, was recently formally described by Blake, Grassle & Eckelbarger (2009). Capitella is a small benthic marine worm with a number of advantages for developmental studies including the ability to maintain it in culture in the laboratory and obtain embryos year round. During embryogenesis, Capitella undergoes an invariant early cleavage program called spiral cleavage, a pattern of early development shared with other lophotrochozoan taxa such as mollusks and nemerteans. Like many polychaetes, Capitella has an indirect life cycle, passing through a planktonic larval phase before undergoing metamorphosis into a juvenile worm. In addition, Capitella has a centralized nervous system composed of a brain and ventral nerve cord.
In addition, because polychaetes continue to add segments into adulthood and have robust regenerative capacities, they offer unique opportunities in which to study the dynamic maintenance of axial position in the adult body. The Capitella genome has recently been sequenced to 8x coverage by the Joint Genome Institute (Department of Energy), providing an important resource to facilitate our studies.
Ongoing projects of the lab include studies of the evolution of the segmented body plan, annelid nervous system development and evolution, patterning of the through gut, evolution of mesoderm, germ line development, molecular mechanisms of early fate specification, establishment of a fate map for the Capitella body plan, and comparative studies with other annelids and vermiform lophotrochozoans such as sipunculids, myzostomids and echiurans.
Elaine C. Seaver, Ph.D.
Professor of Biology
Dr. Seaver obtained a B.S. in biology at McGill University and earned her Ph.D. in biology at the University of Utah.
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