Study on the origin and developing process of genetic diversity in brown bear populations of Hokkaido and areas around the Okhotsk Sea

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The objective of this project was to investigate molecular phylogeography of brown bear populations in Hokkaido and areas around the Okhotsk Sea, and to discuss the origin and developing process of their genetic diversity. The results obtained in this study are as follows:1) The triple population structure of the Hokkaido brown bears, based on molecular phylogeny of mitochondrial DNA (mtDNA), is specific to Hokkaido, and no similar population patterns were found around the Okhotsk Sea areas.2) Ancient mtDNA analyses were made on brown bear bones from the Kafukai A site on Rebun Island of Hokkaido, which is one of Okhotsk Cultural sites developing along coastal regions of the Okhotsk Sea during 5-12 centuries, A.D. Compared the ancient DNA data with modern DNA data of extant brown bears of Hokkaido: three mtDNA lineages occurring separately in north-central, eastern, and southern Hokkaido, ancient DNAs of the Kafukai A site were classified into the north-central or southern Hokkaido lineage. The southern Hokkaido lineage was found in juvenile ancient bears which died in autumn, while the north-central Hokkaido lineage was identified from adults which died in spring. This result indicates that juvenile bears were brought from southern Hokkaido, which was an outside area of the Okhotsk culture and which belonged to the Epi-Jomon or Satsumon culture with a close relation to the Tohoku district of Honshu. In addition, the bear-sending ceremony using kept bears had already been established by the Okhotsk people.3) Ancient DNA data of eastern Hokkaido sites show higher polymorphisms in ancient Hokkaido brown bears than the present bears.4) Two ancient bear bones of Okushiri Island possessed different types of the southern Hokkaido mtDNA lineage, indicating they were from different individuals and brought from southern Hokkaido via human activity.