You are here:
GENETIC DIVERSITY AND STRUCTURE OF AN ESTUARINE FISH (FUNDULUS HETEROCLITIS) INDIGENOUS TO SITES ASSOCIATED WITH A HIGHLY CONTAMINATED URBAN HARBOR
Citation:
MCMILLAN, A., M. BAGLEY, S. JACKSON, AND D. E. NACCI. GENETIC DIVERSITY AND STRUCTURE OF AN ESTUARINE FISH (FUNDULUS HETEROCLITIS) INDIGENOUS TO SITES ASSOCIATED WITH A HIGHLY CONTAMINATED URBAN HARBOR. Ecotoxicology. Springer Science+Business Media, 15(6):539-548, (2006).
Impact/Purpose:
To evaluate population genetic structure and test for effects of intense, multi-generational PCB contamination on genetic diversity
Description:
Intense directional selection on isolated populations can result in loss of genetic diversity, which if persistent, reduces adaptive potential and increases extinction probability. Phenotypic evidence of inherited tolerance suggests that toxic pollutants, specifically, polychlorinated biphenyls (PCBs), have acted as strong selective agents on wild populations of a non-migratory fish, Fundulus heteroclitus, indigenous to heavily contaminated sites. To evaluate population genetic structure and test for effects of intense, multi-generational PCB contamination on genetic diversity, we used AFLP (Amplified Fragment Length Polymorphism) analysis on fish collected from two sites within each of three regions along the east coast of North America that varied widely in PCB contamination. The sites included a heavily contaminated urban harbor (New Bedford, MA), an adjacent moderately-contaminated sub-estuary (Buzzards Bay, MA), and an uncontaminated estuary about 60 km away (Narragansett, RI). AFLP markers distinguished populations at both moderate and small scales, suggesting potential limitations to gene flow at distances of two kilometers or less. No significant differences in genetic diversity were observed across the study sites. Therefore, despite limited gene flow and inferred strong selection by PCB contamination, we found no evidence of a population bottleneck. Genome-wide diversity may have been preserved because of large effective population sizes and/or because the mechanism for genetic adaptation to these contaminants affected only a small number of genetic loci. Alternatively, any loss in diversity may have been restored due to moderate levels of migration and relatively short generation time for this species.