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When evolution is the solution to pollution...
Citation:
Nacci, D. When evolution is the solution to pollution... Wesleyan University Seminar, MIddletown, CT, April 05, 2018.
Impact/Purpose:
This presentation describes genomic evaluations that contribute to our understanding of the ecological and evolutionary risks associated with chronic contaminant exposures to wildlife populations. Here, we assessed genetic and genomic patterns associated with long-term response to an important class of highly toxic environmental pollutants. Specifically, chemical-specific tolerance has rapidly and repeatedly evolved in an estuarine fish species resident to estuaries of the Atlantic U.S. coast. We used field and laboratory studies to characterize variation among fish from populations known to vary in their sensitivity to these pollutants and infer mechanisms of toxicity and tolerance. Results of these studies demonstrate the value of molecular tools to diagnose and predict effects of chemical stressors and characterize the mechanisms and costs of toxic and compensatory responses to chemical stressors by wild populations. General impacts from this contribution include improved understanding by managers and scientists of links between human activities, natural dynamics, ecological stressors and ecosystem condition.
Description:
Rapid evolutionary adaptation is not expected to be sufficiently rapid to buffer the effects of human-mediated environmental changes for most species. Yet large persistent populations of small bodied fish residing in some of the most contaminated estuaries of the US have provided some of the first insights into the types of genomic changes that enable rapid evolutionary rescue from complexly degraded environments. Here we describe how selection by industrial pollutants and other stressors has acted on multiple populations of the Atlantic killifish, Fundulus heteroclitus, and posit that extreme nucleotide diversity uniquely positions this species for successful evolutionary adaptation. Mechanistic studies have identified some of the genetic underpinnings of adaptation to a well-studied class of toxic pollutants; however, multiple genetic regions under selection in wild populations seem to reflect more complex responses to diverse native stressors and/or compensatory responses to primary adaptation. The discovery of these pollution-adapted killifish populations suggests that the evolutionary influence of anthropogenic stressors as selective agents occurs widely. Yet adaptation to chemical pollution in terrestrial and aquatic wildlife will never be a successful ‘solution to pollution’ because potentially adaptive phenotypes may be complex and therefore unlikely to evolve quickly enough, especially in species with small population sizes.