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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Ecotoxicology
COMPARISON OF ALLOZYME FREQUENCIES IN POPULATIONS OF THE RIBBED MUSSEL, GEUKENSIA DEMISSA, IN A PCB-CONTAMINATED ESTUARY AND A REFERENCE SITE.
S.A. Roark and S.I. Guttman. Department of Zoology, Miami University, Oxford, OH 45056
Adaptation to contaminated environments may cause changes in genetic structure that affect the long-term persistence of populations. The ribbed mussel, Geukensia demissa, is abundant in the highly contaminated harbor, New Bedford Harbor (NBH), MA. Total polychlorinated biphenyl (PCB) concentrations in mussel tissues from NBH were two orders of magnitude higher than in those from West Island, a nearby reference site. The goals of this research were 1) to determine if the genetic structure or diversity of ribbed mussel populations from NBH differed from those at West Island, and 2) to determine if allozyme frequencies differed among size classes at either site. Allozyme frequencies at nine polymorphic loci were compared among sites and among size classes. No significant differences existed between sites or among size classes at either site when allele frequencies were compared across loci. Genetic structure differed among sites only at the leucine aminopeptidase (LAP*) locus. LAP* allozymes have been associated with salinity gradients in the blue mussel, Mytilus edulis, therefore salinity could be responsible for the differences observed here. Although evidence for the selective effects of contaminants on allele frequencies was not indicated by these data, genetic adaptation may have occurred at loci not surveyed in this study.
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