The phylogeographic history of the wood frog (Rana sylvatica)

Although the range dynamics of North American amphibians during the last glacial cycle are increasingly better understood, the recolonization history of the most northern regions and the impact of southern refugia on patterns of genetic diversity in these regions are not well reconstructed. In this study I present the phylogeographic history of a widespread and primarily northern frog, Rana sylvatica. For this study, 45 individuals from 34 localities were surveyed for a 700 b p. fragment of cytochrome b and 551 individuals from 116 localities were surveyed for 650 b.p. of the NADH dehydrogenase subunit 2 and tRNATRP mitochondrial genes. Phylogenetic analyses revealed two distinct clades corresponding to eastern and western populations. Phylogeographic patterns within each of these clades revealed similarities as well as differences from patterns found in other species. Specifically, the results corroborate eastern refugia located in the southern Appalachians near present-day North and South Carolina and in the interior plains in the lower Ohio River Valley. Current Maritime populations form a subclade amongst eastern populations and appear to have been colonized from the southern refugium. However, a more northern refugium located in the Appalachian highlands seems to have been source for most other northeastern wood frog populations. Rana sylvatica populations in the Great Lakes region appear to have been colonized from a western refugium located in present-day Wisconsin. This refugium was also a likely source for populations in the species' expansive northwestern range since there is no evidence to support additional, more western refugia.