title: Phylogeography of lemmings (Lemmus): no evidence for postglacial colonization of Arctic from the Beringian refugium.
abstract: Beringia is considered as an important glacial refugium that served as the main source for colonization of formerly glaciated Arctic regions. To obtain high resolution views of Arctic refugial history, we examined mitochondrial cytochrome b phylogeography in the northern genus of rodents, Lemmus (true lemmings), sampled across its circumpolar distribution. Strong phylogeographical structure suggests vicariant separation over several glacial-interglacial periods and does not provide evidence supporting the importance of Beringia for extensive colonization of formerly glaciated regions. Rather than a source of postglacial colonization, Beringia represents an area of intraspecific endemism previously undetected by biogeographical analysis. Existing phylogeographical structure suggests that vicariant separation by glacial barriers was an important factor generating genetic divergence and, thus, increasing genetic diversity in lemmings on continental and circumpolar scales. However, there is little evidence for the direct effect of the last glaciation on the level of genetic variation and allele genealogy in lemmings on a regional geographical scale. This finding implies that the population genetic models of postglacial colonization suggested for temperate taxa might have limited applicability for Arctic species.
authors.affiliation: University of Alaska Museum, Yukon Drive 907, Fairbanks, AK 99775-6960, USA. fnvf@uaf.edu
authors.forename: V B
authors.initials: VB
authors.lastname: Fedorov
authors.forename: A V
authors.initials: AV
authors.lastname: Goropashnaya
authors.forename: M
authors.initials: M
authors.lastname: Jaarola
authors.forename: J A
authors.initials: JA
authors.lastname: Cook
mesh_terms: D000818:Animals; D001110:Arctic Regions; D003411:Arvicolinae / Q000235:genetics / Q000254:growth & development*; D001483:Base Sequence; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D004641:Emigration and Immigration; D004777:Environment; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D003573:Cytochrome b Group; D004272:DNA, Mitochondrial