Meeting Abstract
In wide-ranging species, such as the painted turtle, population genetic structure is anticipated due to limitations on dispersal, particularly in conjunction with local adaptation. However, turtles evolve slowly relative to other lineages, and the painted turtle expressed little genetic variation across its entire range in a previous study. We tested the hypothesis that painted turtles exhibit population genetic structure across the range west of the Mississippi River, an area encompassing enormous temperature and precipitation gradients, using a GBS approach. We sequenced tissue samples from 172 individuals representing seven populations spanning the western range of the painted turtle (northwestern border of Illinois, northern Minnesota, central Kansas, western Nebraska, southern New Mexico, northern Idaho, and northwestern Oregon) and processed SNPs according to GATK Best Practices. We assessed putatively neutral population genetic structure across seven focal populations and tested key demographic hypotheses associated with glaciation and aridification during the Pleistocene, such as the extinction and recolonization of painted turtles in the Great Plains region. Analyses of population structure indicate that, with the exception of Idaho and Oregon, populations are genetically distinct, contrary to prior results from a single mitochondrial locus study. These population genomic patterns may reflect limited dispersal, different population histories, and local adaptation to varied environmental conditions.
