Summary: Molecular Ecology (2003) 12, 711724
© 2003 Blackwell Publishing Ltd
Blackwell Publishing Ltd.
Historical demography and genetic structure of sister
species: deermice (Peromyscus) in the North American
temperate rain forest
XIAOGUANG ZHENG, BRIAN S. ARBOGAST* and G. J. KENAGY
Burke Museum and Department of Zoology, University of Washington, Seattle, Washington 98195, USA
To investigate the evolutionary and biogeographical history of Peromyscus keeni and P.
maniculatus within the coastal forest ecosystem of the Pacific Northwest of North America,
we sampled 128 individuals from 43 localities from southeastern Alaska through Oregon.
We analysed mitochondrial DNA variation using DNA sequence data from the mitochon-
drial cytochrome-b (cyt-b) gene and control region, and we found two distinct clades con-
sistent with the morphological designation of the two species. The sequence divergence
between the two clades was 0.0484 substitutions per site for cyt-b and 0.0396 for the control
region, suggesting that divergence of the two clades occurred during the middle to late
Pleistocene. We also examined the historical demography of the two clades using stepwise
and exponential expansion models, both of which indicated recent rapid population
growth. Furthermore, using the program MIGRATE we found evidence of migration from