Phylogeography of Peromyscus schmidlyi: An endemic of the Sierra Madre Occidental, Mexico

Peromyscus schmidlyi is an endemic rodent from the forested highlands of the Sierra Madre Occidental (SMO) in Mexico. Using 2 genetic markers (cytochrome-b and D-loop) we explored the possible relationship between a recently proposed division of pine-oak forests of the SMO into specific regional communities and patterns of genetic and morphometric variation in P. schmidlyi. We found no genetic structure or significant relationships between either marker and ecological or morphometric variation. Phylogenetic and haplotypic network analyses revealed no geographically structured clusters; phylogenetic trees were shallow and networks were star-shaped. No signal of selection was detected for either marker at the local level. All available evidence suggests that the current distribution of P. schmidlyi is the result of dispersal into the SMO followed by rapid population expansion throughout the area in the late Pleistocene, following the glacial cooling of the SMO highlands.