Two Genetically Distinct Lineages of the Japanese Sika Deer Based on Mitochondrial Control Regions

To investigate genetic diversity among populations of sika deer, Cervus nippon, in Japan, nucleotide sequences (705–824 bases) of the mitochondrial control regions were determined in 61 animals from localities in the Japanese islands and 13 animals from three localities in China. A phylogenetic tree constructed by the sequences indicated that the Japanese sika deer are separated into two distinct lineages: the Northern Japan group (Hokkaido Island and most of the Honshu mainland) and the Southern Japan group (a part of the southern Honshu mainland, Kyushu Island and small islands around Kyushu Island). All sika deer examined in this study shared four to seven units of repetitive sequences (37–40 bases each) within the control region sequences. The number of tandem repeats was different between the two lineages. Six or seven repeats occurred in the northern group, while four or five repeats occurred in the southern group. Based on these control region data, separation of the two lineages was estimated to have occurred approximately 0.35 million years before present. The divergence of the two groups coincides with the last glacial period during the Pleistocene and suggests that there were at least two invasions from the continent to Japan possibly through the land bridges of the Korean Strait.