Phylogeography of Korean raccoon dogs: implications of peripheral isolation of a forest mammal in East Asia

The Korean Peninsula is a problematic place for tracing the evolutionary history of many East Asian species because of its location on the eastern edge of the Eurasian continent. This peninsula probably experienced peripheral isolation as one of several possible Pleistocene refugia. Historical population fluctuations and peripatric speciation of vertebrates in the Korean Peninsula are poorly understood. As an endemic species in East Asia, the raccoon dog Nyctereutes procyonoides is an appropriate model for describing the evolutionary history of mammal species in the Korean Peninsula. Therefore, we used mitochondrial cytochrome b sequences of raccoon dogs from Korea, Russia, China, Vietnam and Japan to test four hypotheses: (1) during glacial periods, a single contiguous refugium may have existed in north‐eastern Asia that permitted genetic exchange between raccoon dogs from Korea and Japan; (2) the presence of one large refugium did not permit gene flow between raccoon dogs in Korea and Japan; (3) several refugia existed on the north‐east Asian mainland, one located in the southern part of the Korean Peninsula, with some population movement to Japan; (4) the presence of several refugia, but no gene flow between the raccoon dogs of Korea and Japan. Our results support the last hypothesis. Haplotype distributions indicate postglacial expansion of raccoon dogs in the Korean Peninsula. Conspicuous genetic differences between Japanese and continental populations might be the result of limited gene flow after geographical isolation. This phylogeographical pattern shows the effect of peripheral isolation in the Korean Peninsula, the southernmost refugium for raccoon dogs.