A genetic record of population isolation in pocket gophers during Holocene climatic change.
A long-standing question in Quaternary paleontology is whether climate-induced, population-level phenotypic change is a result of large-scale migration or evolution in isolation. To directly measure genetic variation through time, ancient DNA and morphologic variation was measured over 2,400 years in a Holocene sequence of pocket gophers (Thomomys talpoides) from Lamar Cave, Yellowstone National Park, Wyoming. Ancient specimens and modern samples collected near Lamar Cave share mitochondrial cytochrome b sequences that are absent from adjacent localities, suggesting that the population was isolated for the entire period. In contrast, diastemal length, a morphologic character correlated with body size and nutritional level, changed predictably in response to climatic change. Our results demonstrate that small mammal populations can experience the long-term isolation assumed by many theoretical models of microevolutionary change.
Hadly
E A
EA
Mountain Research Center and Department of Biology, Montana State University, Bozeman, MT 59717, USA. liz@peak.mrc.montana.edu
Kohn
M H
MH
Leonard
J A
JA
Wayne
R K
RK
D005075:Biological Evolution; D003573:Cytochrome b Group / Q000235:genetics; D004247:DNA / Q000032:analysis*; D014644:Genetic Variation; D005828:Genetics, Population; D006801:Humans; D010163:Paleontology
D003573:Cytochrome b Group; D004247:DNA