Project title: Population genetic structure of eastern painted turtles in Rhode Island
Mentors: Scott W. Buchanan and Dr. Nancy E. Karraker
Abstract: Roads can be a major obstacle to movement across the landscape for certain animals, potentially isolating wildlife populations genetically. The objective of this study was to find out whether interstate highways serve as barriers to genetic connectivity among Rhode Island’s eastern painted turtle (Chrysemys p. picta) populations. We sampled 658 individuals from 23 wetlands throughout the state and genotyped them across 18 microsatellite loci. A STRUCTURE analysis revealed population genetic structure that showed no differentiation based on position to the interstate highways. This was confirmed with low FST values between populations and similar values for indices of diversity across all populations (mean AR = 5.593, SE = 0.049; mean HO = 0.659, SE = 0.018; mean HE = 0.632, SE = 0.017). Contrary to expectations, our results suggest that the population of eastern painted turtles in Rhode Island is panmictic and not subject to gene flow restriction due to the interstate highways. This might be explained by the recent construction of the highways relative to post-glacial recolonization of the Northeast. Gene flow can also be maintained through use of waterways that flow under the highways or human-mediated factors such as pet release.