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Research Publications: UM-SG-RS-2006-11
Title:
Isolation by distance in the eastern oyster, Crassostrea virginica, in Chesapeake Bay.
Year:
2006Authors:
Rose, CG; Paynter, KT; Hare, MPSource:
Journal of Heredity 97 ( 2 ) : 158 - 170DOI:
10.1093/jhered/esj019Abstract:
Intensive efforts are underway to restore depleted stocks of Crassostrea virginica in Chesapeake Bay. However, the extent of gene flow among local populations, an important force mediating the success of these endeavors, is poorly understood. Spatial and temporal population structures were examined in C. virginica from Chesapeake Bay using eight microsatellite loci. Deficits in heterozygosity relative to Hardy-Weinberg expectations were seen at all loci and were best explained by null alleles. Permutation tests indicated that heterozygote deficiency reduced power in tests of differentiation. Nonetheless, genotypic exact tests demonstrated significant levels of geographic differentiation overall, and a subtle pattern of isolation by distance (IBD) was observed. Comparisons between age classes failed to show differences in genotype frequencies, allelic richness, gene diversity, or differentiation as measured by F(ST), contrary to predictions made by the sweepstakes hypothesis. The IBD pattern could reflect an evolutionary equilibrium established because local gene flow predominates, or be influenced in either direction by recent anthropogenic activities. An evolutionary interpretation appears justified as more parsimonious, implying that local efforts to restore oyster populations will have local demographic payoffs, perhaps at the scale of tributaries or regional subestuaries within Chesapeake Bay.
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Featured Fellow
Leone Yisrael is a cephalopod-loving scuba diver, cook, and loves to try new activities. She conducts genetic analysis and fieldwork at the Smithsonian Environmental Research Center through the Coastal Disease Ecology Lab.
Featured Research Project
Developing a habitat model for mysids, an important link in Chesapeake Bay food webs
Mysids are important mesozooplankton prey for many species of fish in Chesapeake Bay and are an important link in transferring energy from lower to upper trophic levels. Mysids also serve as biological vectors for benthic-pelagic coupling due to their diel vertical migration and omnivorous prey-switching behavior, which makes mysids important regulators of food web architecture. Despite their central role in coastal food webs, surprisingly little is known about mysid ecology and dynamics in Chesapeake Bay.
