Genetic basis for rapidly evolved tolerance in the wild: adaptation to toxic pollutants by an estuarine fish species.
Atlantic killifish (Fundulus heteroclitus) residing in some urban and industrialized estuaries of the US eastern seaboard demonstrate recently evolved and extreme tolerance to toxic aryl hydrocarbon pollutants, characterized as dioxin-like compounds (DLCs). Here, we provide an unusually comprehensive accounting (69%) through quantitative trait locus (QTL) analysis of the genetic basis for DLC tolerance in killifish inhabiting an urban estuary contaminated with PCB congeners, the most toxic of which are DLCs. Consistent with mechanistic knowledge of DLC toxicity in fish and other vertebrates, the aryl hydrocarbon receptor (ahr2) region accounts for 17% of trait variation; however, QTL on independent linkage groups and their interactions have even greater explanatory power (44%). QTL interpreted within the context of recently available Fundulus genomic resources and shared synteny among fish species suggest adaptation via interacting components of a complex stress response network. Some QTL were also enriched in other killifish populations characterized as DLC-tolerant and residing in distant urban estuaries contaminated with unique mixtures of pollutants. Together, our results suggest that DLC tolerance in killifish represents an emerging example of parallel contemporary evolution that has been driven by intense human-mediated selection on natural populations.
U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, 27 Tarzwell Dr., Narragansett, RI, 02882, USA. Nacci.diane@epa.gov.
Diane
D
Nacci
U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, 27 Tarzwell Dr., Narragansett, RI, 02882, USA.
Dina
D
Proestou
U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, 27 Tarzwell Dr., Narragansett, RI, 02882, USA.
Denise
D
Champlin
U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA.
John
J
Martinson
U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA.
Eric R
ER
Waits
D000222:Adaptation, Physiological / Q000235:genetics*; D000818:Animals; D004147:Dioxins; D063366:Estuaries; D019143:Evolution, Molecular; D005260:Female; D029941:Fish Proteins / Q000235:genetics; D023781:Fundulidae / Q000235:genetics*; D008281:Maine; D008297:Male; D040641:Quantitative Trait Loci; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics*; D012237:Rhode Island; D014874:Water Pollutants, Chemical
D004147:Dioxins; D029941:Fish Proteins; D018336:Receptors, Aryl Hydrocarbon; D014874:Water Pollutants, Chemical
adaptation; contemporary evolution; dioxin; evolved tolerance; quantitative trait locus