Spatial patterns of neutral and functional genetic variations reveal patterns of local adaptation in raccoon (Procyon lotor) populations exposed to raccoon rabies Journal Articles uri icon

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abstract

  • AbstractLocal adaptation is necessary for population survival and depends on the interplay between responses to selective forces and demographic processes that introduce or retain adaptive and maladaptive attributes. Host–parasite systems are dynamic, varying in space and time, where both host and parasites must adapt to their ever‐changing environment in order to survive. We investigated patterns of local adaptation in raccoon populations with varying temporal exposure to the raccoon rabies virus (RRV).RRVinfects approximately 85% of the population when epizootic and has been presumed to be completely lethal once contracted; however, disease challenge experiments and varying spatial patterns ofRRVspread suggest some level of immunity may exist. We first assessed patterns of local adaptation in raccoon populations along the eastern seaboard ofNorthAmerica by contrasting spatial patterns of neutral (microsatellite loci) and functional, major histocompatibility complex (MHC) genetic diversity and structure. We explored variation ofMHCallele frequencies in the light of temporal population exposure toRRV(0–60 years) and specificRRVstrains in infected raccoons. Our results revealed high levels ofMHCvariation (66DRBexon 2 alleles) and pronounced genetic structure relative to neutral microsatellite loci, indicative of local adaptation. We found a positive association linkingMHCgenetic diversity and temporalRRVexposure, but no association with susceptibility and resistance toRRVstrains. These results have implications for landscape epidemiology studies seeking to predict the spread ofRRVand present an example of how population demographics influence the degree to which populations adapt to local selective pressures.

authors

  • Kyle, Christopher J
  • Rico, Yessica
  • Castillo, Sarrah
  • Srithayakumar, Vythegi
  • Cullingham, Catherine I
  • White, Bradley
  • Pond, Bruce A

publication date

  • May 2014