Influence of Quaternary environmental changes on mole populations inferred from mitochondrial sequences and evolutionary rate estimation

Quaternary environmental changes fundamentally influenced genetic diversity of the temperate-zone terrestrial animals, including those on the Japanese Archipelago. The genetic diversity of present-day populations are taxon and region specific, but its determinants are poorly understood. Here, we analyzed cytochrome b gene (Cytb) sequences (1,140 bp) of mitochondrial DNA (mtDNA) to elucidate factors determining the genetic variation in three species of large moles: Mogera imaizumii and Mogera wogura occur in Northern and Southern mainland Japan (Honshu, Shikoku, and Kyushu), and Mogera robusta occurs on the nearby Asian continent. Network construction with the Cytb sequences revealed 10 star-shaped clusters with apparent geographic affinity. Mismatch distribution analysis showed that modes of pairwise nucleotide differences (t values) were grouped into five classes in terms of the level, implying the occurrence of five stages for the rapid expansion. It is conceivable that a severe cold ...