Mitochondrial DNA haplogrouping of the Okhotsk people based on analysis of ancient DNA: an intermediate of gene flow from the continental Sakhalin people to the Ainu

In order to further understand the genetic status of the Okhotsk people, who were distributed in southern coastal regions of the Okhotsk Sea during the 5th-13th centuries, nucleotide variations in the hypervariable region (HVR) and the coding regions of mitochondrial DNA (mtDNA) were analyzed. Targeting the coding regions provides reliable genetic information even from ancient DNAs that may have suffered post-mortem damage. MtDNA haplogroups of 38 individuals were classified according to mtDNA lineages known in northeastern Asian people. Comparisons of mtDNA haplogroup frequencies between the Okhotsk people and other Asian populations revealed that the genetic structures of the Okhotsk people are very similar to those of populations currently living around lower regions of the Amur River and the Ainu of Hokkaido. The results support our previous Study on molecular phylogeny of mtDNA HVR I sequences, and strongly suggest that the Okhotsk people originated around the lower regions of the Amur River and became an intermediate of gene flow from the continental Sakhalin people to the Ainu.