Genetic structuring of relict populations of Gapper's red-backed vole (Clethrionomys gapperi)

Abstract

We evaluated genetic variation in Gapper's red-backed vole (Clethrionomys gapperi) at 2 microsatellite DNA loci and related our results to the biogeographic history of the southern Appalachians. To investigate population genetic structuring within relictual habitats, 222 individuals were sampled from 9 sites, including 2 populations suspected to have been isolated since the Wisconsin glacial retreat. Genetic structuring was evident among the majority of the sampled populations. Unbiased estimates of exact P-values revealed significant allelic differentiation between 15 of 36 population pairs. Overall estimates of FST and ρ were 0.07 and 0.10, respectively, indicating moderate genetic subdivision. Overall gene flow was estimated indirectly with 3 methods and was 1.13-4.44 migrants/generation. The hypothesized isolation of 2 islandlike populations at Massanutten and Peaks of Otter was supported by our data and was most apparent in the Massanutten population, where genetic diversity was low compared with all other populations. The unique genetic structure of the population at Massanutten also may be related to habitat disturbances. Genetic patterns observed in relict populations of the red-backed vole may provide insight into genetic structuring of codistributed boreal populations in the southern Appalachians.