title: Population genetic structure of a nonmigratory estuarine fish (Fundulus heteroclitus) across a strong gradient of polychlorinated biphenyl contamination.
abstract: Populations of the estuarine fish Fundulus heteroclitus indigenous to contaminated sites exhibit heritable resistance to some of the toxic effects of early life-stage exposure to polychlorinated biphenyls (PCBs). This evolved tolerance provides evidence of strong selection by PCBs, and it suggests other potential genetic effects of these stressors on resident populations. Environmental contaminants have the potential to affect the genetic structure of populations and to reduce genetic diversity, but species life-history traits, particularly patterns of migration and dispersal, also influence the distribution of genetic variation among populations. Therefore, the present was conducted to determine whether genetic diversity or genetic structure is altered in populations of F. heteroclitus indigenous to 18 sites in Massachusetts (USA) and Rhode Island (USA), representing a steep gradient of sediment PCB contamination and culminating in a Superfund site at New Bedford Harbor (NBH; MA, USA). Allele frequencies at enzymatic loci were used to assess genetic structure and diversity. Selection experiments using a highly toxic PCB congener (3,3',4,4',5-pentachlorobiphenyl) were conducted to determine if genetic patterns at field sites could be associated with contaminant exposures. Although allele frequencies clearly reflected a pattern of isolation by distance, the results indicated neither significant loss of genetic diversity nor alteration of allele frequencies for populations of F. heteroclitus in NBH.
authors.affiliation: Department of Zoology, Miami University, Oxford, Ohio 45056, USA. shaun.roark@noaa.gov
authors.forename: Shaun A
authors.initials: SA
authors.lastname: Roark
authors.forename: Diane
authors.initials: D
authors.lastname: Nacci
authors.forename: Laura
authors.initials: L
authors.lastname: Coiro
authors.forename: Denise
authors.initials: D
authors.lastname: Champlin
authors.forename: Sheldon I
authors.initials: SI
authors.lastname: Guttman
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D004798:Enzymes / Q000235:genetics; D023781:Fundulidae / Q000235:genetics*; D005787:Gene Frequency; D014644:Genetic Variation; D005838:Genotype; D019015:Geologic Sediments / Q000032:analysis; D008404:Massachusetts; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity*; D011153:Population; D012237:Rhode Island; D016019:Survival Analysis; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D004798:Enzymes; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls