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Phylogeography and paleoclimatic range dynamics explain variable outcomes to contact across a species' range
  • Keric Lamb,
  • Catherine Debban,
  • Laura Galloway
Keric Lamb
University of Virginia

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Catherine Debban
University of Virginia Center for Public Health Genomics
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Laura Galloway
University of Virginia
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Replicability of speciation and the maintenance of divergence after contact are poorly characterized processes, particularly in context of phylogeography and post-glacial range dynamics. Using contact zones located at the leading- and rear-edges of a species' range, we examined variation in outcomes to contact between divergent lineages of Campanula americana. We investigated whether contact zones vary in quantity and directionality of gene flow, how phylogeographic structure differs between contact zones, and how historic range dynamics may affect outcomes to contact. We found that all contact zones formed at similar times via secondary contact yet detected significant admixture in only the rear-edge contact zone. Across all contact zones, gene flow was asymmetric. Our results emphasize the dependence of speciation processes on phylogeographic structure, demographic history, and paleoclimatic range dynamics. Our results suggest that caution need be taken when treating species as cohesive or uniform evolutionary units.