Intraspecific phylogeny and nucleotide diversity of the least shrews, the Sorex minutissimus-S. yukonicus complex, based on nucleotide sequences of the mitochondrial cytochrome b gene and the control region

Abstract

Phylogenetic analysis was conducted for various populations of the Sorex minutissimus-S. yukonicus complex based on mitochondrial gene (cytochrome b and/or the control region) sequences. Sorex minutissimus was divided into some monophyletic groups in Eurasia; it was divided into 2 main groups, eastern and western Eurasian clades, based on combined data of the cytochrome b and the control region. Monophyly of shrews from Hokkaido-Sakhalin, Primorye, Mongolia-Transbaikalia, southeastern Finland was strongly supported respectively in most analyses. Sorex yukonicus was phylogenetically close to S. minutissimus in eastern Siberia. Some shrews from western and central Siberia were included in the clade of southeastern Finland. Also, most shrews from central-northern Finland and Norway made a clade close to but different from the southeastern Finland clade. This finding suggests that Fennoscandian shrews might consist of individuals which were recolonised from various refugia after the Last Glacial Maximum. Nucleotide diversity of shrews from Hokkaido and Alaska was low. Three regional groups in Kamchatka-Sakha, Sakhalin, and Mongolia-Transbaikalia tended to have medium nucleotide diversity. In contrast, shrews from Cisbaikalia-western Siberia and Fennoscandia had high nucleotide diversity. The S. minutissimus-S. hosonoi group appears to have experienceed a quit different biogeographic history from two shrews with similar ranges, the S. caecutiens-S. hosonoi group and S. tundrensis. © 2012 The Mammal Society of Japan.