The Okhotsk culture: who were the Okhotsk people who are hypothesized to have merged with the Hokkaido Jomon and Satsumon to form the Ainu people?
To investigate the phylogenetic relationships between the Okhotsk people and modern Asian populations, the NJ relationships among the 17 Asian populations were con- structed (Fig. 3). In this phylogenetic tree, the Okhotsk people were clustered with the Nivkhi, Ulchi, Negidal, Koryak, and Even. Among them, the Nivkhi and Ulchi were much closer to the Okhotsk people, and clustered with more than 70% bootstrap values. The close relatedness among the three populations was in congruence with the high degree of sharing of mtDNA haplotypes. On the other hand, the Ainu people were phylogenetically distant from the Okhotsk people (Fig. 3). However, the dA distance(0.068%, Table 3) between the Okhotsk people and the Ainu was smaller than those between the Okhotsk and other populations except the Nivkhi and Ulchi. Moreover, multidimensional scaling analysis (two-dimensional dis- play, Fig. 4) of the genetic relationships among the 17 Asian populations based on dA distances showed that the Nivkhi, Ulchi, Negidal and Ainu were much closer to the Okhotsk people than the other Asian populations. These findings demonstrate that the Okhotsk people are closely related to modern populations distributed around the Sakhalin and downstream of the Amur River as well as to the Ainu people of Hokkaido.
Six haplotypes identified (types 2, 5, 6, 10, 15, 16) were specific to the Okhotsk people (Table 1). This finding shows that the Okhotsk people were genetically differentiated from other Asian populations. On the other hand, identification of the other ten haplotypes (types 1, 3, 4, 7, 8, 9, 11, 12, 13 and 14) from the Okhotsk people implies a close genetic relationship between the Okhotsk people and other northeastern Asian populations. In particular, the Okhotsk people had higher genetic affinities with the Nivkhi and Ulchi among the compared northeastern Asian populations (Figs. 3, 4). The Nivkhi and Ulchi populations are currently distributed in areas geographically close to the Okhotsk culture sites (Figs. 1, 2). Among haplotypes 12, 13 and 14 identified from 11 Okhotsk people, a unique combination of four transitional mutations (16189C- 16231C-16266T-16519C for types 12, 13 and 14) was shared and regarded as the motif sequence for mtDNA haplogroup ‘‘Y1’’ reported by Kivisild et al. (2002). Recent studies have shown that most people with haplogroup Y1 are distributed in northern Asia and Siberia (Schurr et al. 1999; Kivisild et al. 2002). Moreover, Adachi et al. (2006) reported that haplogroup Y occurred in the Ainu of Hokkaido but not in the Jomon people of Hokkaido. In the present study, we found that the Okhotsk people shared haplogroup Y1 at a similar frequency (30%, 11/37) to the Nivkhi (35%, 20/57) and the Ulchi (31%, 27/87) (Table 2). The result also suggests that the Okhotsk people are genetically closer to the Nivkhi and Ulchi because of the similarity in the frequencies of haplogroup Y1 between them. Moreover, haplogroup Y1 was shared also by the Ainu (6%, 3/51) (Table 2). That the frequency of Y1 is higher in the Okhotsk people (30%) than the Ainu (6%) suggests gene flow from the Okhotsk people to the Ainu. In addition, other haplotypes clarified to haplogroup Y1 were found: for example, two types from two individuals of the Ulchi, two types from six individuals of the Nivkhi, and one type from seven individuals of the Ainu. When these numbers are included, the same direction of gene flow is still apparent. Tajima et al. (2004) examined mtDNA phylogeny of modern Asian people (not including the Okhotsk people) and reported that there was gene flow from the Nivkhi to the Ainu. The present study demonstrates that the Okhotsk people were an intermediate in the gene flow from the Nivkhi to the Ainu.
In previous morphological studies, Mitsuhashi and Yamaguchi (1961) reported that skeletons of the Okhotsk people had morphological characteristics similar to those of northeastern Asian people. In addition, Yamaguchi(1974) and Ishida (1988, 1996) reported, based on cranial measurements, that the Okhotsk people were closer to populations that are currently distributed downstream of the Amur River. Moreover, Utagawa (2002) reported that evidence for the occurrence of bear-sending ceremonies, as seen in the Ainu culture, was found from archaeological sites of the Okhotsk culture. Rituals using brown bears are thought to be one proto-type of ‘‘Iomante,’’ which has been performed as a bear-sending ceremony in the Ainu culture. Therefore, archaeologists have generally assumed that the Okhotsk culture joined the Satsumon culture (eighth to fourteenth centuries; direct descendants of the Jomon people in Hokkaido) resulting in establishment of the Ainu culture. The direction of gene flow obtained in the present study is in agreement with the interpretation based on previous morphological and archaeological data. These facts demonstrate that the Okhotsk people could have originated from northeastern Asian populations such as the Nivkhi and Ulchi currently living around Sakhalin and downstream of the Amur River, and support the hypothesis that the Okhotsk people could have joined the Satsumon people resulting in the Ainu culture.
Kikuchi (2004) reported that walrus tusks excavated from archaeological sites of the Okhotsk culture could have been brought from the ancient Koryak culture to the Okhotsk culture, because walrus are currently distributed in the Arctic sea and the Bering sea. In the present study, the Okhotsk people were found to have some genetic affinities with the Koryak and the Even living around the Kamchatka peninsula (Table 2; Fig. 3). These facts suggest that there were genetic and cultural exchanges between the Okhotsk people and the Koryak and Even.
In conclusion, the present study has provided new status of the Okhotsk people. Unique maternal genetic features of the Okhotsk people identified by ancient mtDNA analysis demonstrated their genetic differentiation and some genetic affinity with geographically neighboring modern populations such as the Nivkihi and Ulchi. The molecular phylogenetic data of the present study support the previous anthropological discussion based on morphological and archaeological data.
Molecular phylogenetic relationships between the Okhotsk people and modern Asian populations
Nearby Hokkaido, on the Kamchatka peninsula are possible sources of Mtdna has G, Y ( and Z).
Schurr et al., Mitochondrial DNA variation in Koryaks and Itel’men: population replacement in the Okhotsk Sea-Bering Sea region during the Neolithic.– Semantic Scholar / American journal of physical anthropology 1999DOI:10.1002/(SICI)1096-8644(199901)108:1<1::AID-AJPA1>3.0.CO;2-1
In this study, we analyzed the mitochondrial DNA (mtDNA) variation in 202 individuals representing one Itel’men and three Koryak populations from different parts of the Kamchatka peninsula. All mtDNAs were subjected to high resolution restriction (RFLP) analysis and control region (CR) sequencing, and the resulting data were combined with those available for other Siberian and east Asian populations and subjected to statistical and phylogenetic analysis. Together, the Koryaks and Itel’men were found to have mtDNAs belonging to three (A, C, and D) of the four major haplotype groups (haplogroups) observed in Siberian and Native American populations (A-D). In addition, they exhibited mtDNAs belonging to haplogroups G, Y, and Z, which were formerly called “Other” mtDNAs. While Kamchatka harbored the highest frequencies of haplogroup G mtDNAs, which were widely distributed in eastern Siberian and adjacent east Asian populations, the distribution of haplogroup Y was restricted within a relatively small area and pointed to the lower Amur River-Sakhalin Island region as its place of origin. In contrast, the pattern ofdistribution and the origin of haplogroup Z mtDNAs remained unclear. Furthermore, phylogenetic and statistical analyses showed that Koryaks and Itel’men had stronger genetic affinities with eastern Siberian/east Asian populations than to those of the north Pacific Rim. These results were consistent with colonization events associated with the relatively recent immigration to Kamchatka of new tribes from the Siberian mainland region, although remnants of ancient Beringian populations were still evident in the Koryak and Itel’men gene pools.
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