Thomas J. Hilbish Professor of Biological Sciences Ph.D., 1984, State University of New York at Stony Brook. 803-777-6629 hilbish@biol.sc.edu

Ecological Genetics, Physiological Ecology of Marine Invertebrates

Dr. Hilbish's research program concentrates on the genetic and physiological properties of diverging populations. This research emphasizes marine invertebrates, particularly bivalves. A knowledge of the genetic structure physiological variation is imperative to an understanding of evolution at the physiological level. Current research programs focus in three areas. First, we are continuing studies on a genetic polymorphism at the enzyme coding gene aminopeptidase-1, in the mussel Mytilus edulis . We have previously demonstrated this locus to be the subject of strong natural selection. Coordinated studies of the population, biochemical, physiological and ecological genetics of this locus have led to a mechanistic understanding natural selection at this locus that rivals the classic studies on sickle cell in humans. Presently we are examining the effects of this locus on growth and reproduction as components of fitness. A second research area concerns the quantitative genetics of physiological variation in the marine clam, Mercenaria mercenaria . This study measures the total genetic variance for the physiological traits that make up the energy budget in this species. An understanding of the magnitude of genetic variance for these traits and the genetic interactions among traits is the key to understanding the evolution of physiological races. Our third research area concerns the evolutionary divergence of two populations of Mytilus in Europe. Populations separated during the Pleistocene have evolved discrete physiological properties that leads to them exhibiting different geographic distributions. We are presently determining the extent of this physiological evolution and are beginning to develop a genetic map of genes responsible for this divergence. This study will provide a genetic understanding of population divergence and incipient speciation in these mussels.

Selected Publications:

Hilbish, T.J. and K.M. Zimmerman. 1988. Genetic and nutritional control of the gametogonic cycle in Mytilus edulis. Mar. Biol. 98:223-228.

Rawson, P.D. and T.J. Hilbish. 1990. Heritability of juvenile growth for the hard clam Mercenaria mercenaria. Mar. Biol. 105:429-436.

Rawson, P.D. and T.J. Hilbish. 1991. Genotype-environment interaction for juvenile growth in the hard clam Mercenaria mercenaria . (L.). Evolution 45:1924-1935.

Hawkins, A. J. S. and T. J. Hilbish. 1992. The costs of cell volume regulation: protein metabolism during hyperosmotic adjustment. J. Mar. Biol. Ass. U. K. 72:569-578.

Hilbish, T. J., A. Day, and B. L. Bayne. 1994. Genetics of physiological variation within the mussel genus Mytilus. Evolution. 48:267-286.

Hilbish, T. J. and M. Goodwin. 1994. A simple demonstration of natural selection in the wild using the common dandelion. Amer. Biol. Teacher. 56:286-290.

Heath, D. D., R. H. Devlin, T. J. Hilbish, and G. K. Iwama. 1995. Multi-locus DNA fingerprints in seven species of salmonids. Can. J. Zool. 73:600-606.

Rawson, P. D. and T. J. Hilbish. 1995. Evolutionary relationships among male and female mitochondrial DNA lineages in the Mytilus edulis species complex. Molec. Biol. Evol. 12:893-901.

Rawson, P.D. and T. J. Hilbish. 1995. Distribution of male and female transmitted mitochondrial lineages in the mussels Mytilus trossulus and M. galloprovincialis on the west coast of North America. Mar. Biol. 124:245-250.

O'Foighil, D., P. M. Gaffney, and T. J. Hilbish. 1995. Differences in mitochondrial 16s ribosomal gene sequences allow discrimination among American (Crassostrea viriginica Gmelin) and Asian (C. gigas Thunberg, C. ariakensis Wakiya) oyster species. J. Exp. Mar. Biol. Ecol. 192:211-220.

O'Foighil, D., Hilbish, T. J., and R. M. Showman. 1996. Mitochondrial gene variation in Mercenaria clam sibling species reveals a relict secondary contact zone in the western Gulf of Mexico. Mar. Biol. 126:675-683.

Rawson, P. D., C. L. Secor, and T. J. Hilbish. 1996. The effects of natural hybridization on the inheritance of male and female mitochondrial DNA lineages in the blue mussel (Mytilus). Genetics. 144:241-248.

Hilbish, T. J. 1996. Population genetics of marine species: the interaction of natural selection and historically differentiated populations. J. Exp. Mar. Biol. Ecol. 200:67-84.