Genetic Structuring in the Thirteen-Lined Ground Squirrel (Spermophilus Tridecemlineatus): Testing the Central/Peripheral Model and Colonization Patterns

by Kalkvik, Håkon M.

The Central/Peripheral model states that because of small population size, isolation, and marginal habitat in the periphery, peripheral populations have lower genetic diversity than central populations. This model was tested on the Thirteen-lined ground squirrel, a widely distributed mammal whose eastern range expanded with the retreat of the Wisconsin glacier and landscape opening by agricultural practices and lumbering. The species may have expanded into Ohio from the northwest, from Indiana in the west, or from a refugia within central Ohio. Fresh and museum specimens were collected from across their eastern range, from central populations in Nebraska to the eastern periphery in Ohio. Quickly evolving microsatellites were used to determine genetic variation among the sample populations. The Central/Peripheral model was not supported because no difference in genetic diversity was observed between central and peripheral populations. The genetic evidence supports a southeastern Ohio colonization from Indiana in the west.