Phylogeography of the Brown Bear (Ursus arctos) and Bear-Human Relationships in the Far East, Including Hokkaido Island, Japan

This chapter discusses the phylogeography of the brown bear and bear-human relationships in the Far East, including Japan, based on genetic data from our lab. The maternally inherited mitochondrial DNA (mtDNA) phylogeography of brown bears in the Northern Hemisphere has been studied for the past 30 years. Given the female philopatry of this species, geographic information on mtDNA distribution provides invaluable insights into the migration history of the bears across their wide range. The brown bear population on Hokkaido Island, northern Japan, comprises three distinct mtDNA lineages, which can be called a “triple mtDNA population structure”, compared with those of the Eurasian and American continents. By contrast, an analysis of paternally inherited Y-chromosomal DNA from male bears showed no evidence of intra-population structure on Hokkaido, like that of the triple structure identified from mtDNA analyses. This difference might have arisen through male-mediated gene flow among local natal populations, combined with founder effects and subsequent genetic drift after the bears’ immigration to Hokkaido from the continent. In addition, a whole-genomic analysis revealed that the Hokkaido bear population formed a different clade from those in Europe and North America, suggesting that it maintained some genetic diversity even after geographical isolation on the island. The genetic uniformity within the Hokkaido population could have resulted from male-mediated gene flow, and this is congruent with the Y-chromosomal DNA data. Genetic data on brown bears can sometimes be useful for studies of the bear-human relationships that have developed in indigenous cultures. For example, the iomante bear-sending ritual performed in the Ainu Culture on Hokkaido involves juvenile bears, and knowing its origin is very important for understanding cultural history and development in the context of archaeology and ethnology. Analyses of ancient mtDNA from bear remains excavated from the Okhotsk Cultural archaeological site on Rebun Island, northern Hokkaido, clarified that the iomante ritual could have originated in the Okhotsk Culture, and that people in different ancient cultures had similarly imparted significance to and placed high value on juvenile brown bears, which functioned in intercultural communication and bonding.