University of Hawaii
Kewalo Marine Laboratory
41 Ahui Street
Honolulu, HI 96813

Telephone: (808) 539-7324
Fax: (808) 599-4817
E-mail Address: seaver@hawaii.edu

Research Interests:

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.

Current Research:

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, http://genome.jgipsf.org/Capca1/Capca1.home.html), 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.

Selected References:

• Meyer, N. P. and Seaver, E. C. (2009).Neurogenesis in an annelid: characterization of neural progenitors in the polychaete Capitella sp. I. Developmental Biology doi:10.1016/j.ydbio.2009.06.017.
• Boyle, M.J. and Seaver, E.C. (2009) Evidence of a dorsal pharynx in the marine polychaete, Capitella sp. I (Polychaeta: Capitellidae). Zootaxa 2: 317-328.
• Fröbius, A.C., Matus, D.Q., and Seaver E.C. (2008) Genomic Organization and Expression Demonstrate Spatial and Temporal Hox Gene Colinearity in the Lophotrochozoan Capitella sp. I. PLoS ONE 3(12): e4004. doi:10.1371/journal.pone.0004004
• Dill, K.K. and Seaver, E.C. (2008)Vasa and nanos are co-expressed in somatic and germ line tissue from early embryonic cleavage stages through adulthood in the polychaete Capitella sp. I. Development, Genes and Evolution 218(9):453-63.
• Thamm, K. and Seaver, E. C. (2008) Notch, Delta and hes gene expression during larval and juvenile segmentation in the polychaete annelid Capitella sp. I. Developmental Biology 320(1):304-318.
• Boyle, M. J. and Seaver, E. C. (2008) Developmental expression of foxA and gata genes during gut formation in the polychaete annelid, Capitella sp. I. Evolution and Development 10(1):89-105.
• Dill, K. K., Thamm, K. and Seaver, E. C. (2007) Characterization of twist and snail gene expression during mesoderm and nervous system development in the polychaete annelid Capitella sp. I. Development, Genes and Evolution 217(6):435-47.
• Fröbius, A. C. and Seaver, E. C. (2006) Capitella sp. I EBX, the first lophotrochozoan member of a novel paired-like homeobox gene family. Mechanisms of Development 6(8):985-91.
• Irvine, S. Q. and Seaver, E. C. (2006). Early Annelid Development, A Molecular Perspective. in Greg Rouse and Fredrick Pleijel, eds. Reproductive Biology and Phylogeny of Annelida. Pp. 93-140. Reproductive Biology and Phylogeny, v. 4. Barrie G.M. Jamieson, series ed. Science Publishers: Enfield, NH.
• Fröbius, A. C. and Seaver, E. C. (2006) ParaHox gene expression in the polychaete annelid Capitella sp. I. Development, Genes and Evolution 216(2): 81-88.
• Seaver, E. C. and Kaneshige, L. M. 2006. Expression of 'segmentation' genes during larval and juvenile development in the polychaetes Capitella sp. I and H. elegans. Developmental Biology 289: 179-194.
• Seaver, E. C. , Thamm, K., and Hill, S. (2005) Growth patterns during segment formation in the two annelids Capitella sp. I and Hydroides elegans: comparisons at distinct life history stages. Evolution and Development 7(4): 312-326.
• Seaver, E. C. (2003) Segmentation: mono or polyphyletic? Int. J. Dev Biol. 47: 583-595.
• Seaver, E. C., Paulson, D., Irvine, S. Q. and Martindale, M. Q. (2001) The spatial and temporal expression the Ch-en, the engrailed gene in the polychaete Chaetopterus does not support a role in body axis segmentation. Developmental Biology 236: 195-209.
• Shankland, M., and Seaver, E. C. (2000) Evolution of the bilaterean body plan: what have we learned from annelids? PNAS 97: 4434-4437.
  

seaver@hawaii.edu