Comparative studies of the Ainu, their ancestors, and neighbors: assessment based on metric and nonmetric dental data

抄録

Using Mahalanobis’ generalized distance for odontometric data and Smith’s mean measure of divergence for nonmetric dental data, interpopulation similarities between four local Ainu groups from Sakhalin Island and Hokkaido, as well as their supposedly ancestral and neighboring populations, were analyzed. In this study, multidimensional scaling and multidimensional plots by Andrews were applied to the distance matrices to visualize the intergroup relationships. The results obtained reconfirm the dental association between the prehistoric Jomon and the recent Ainu. However, the diversity of the recent Ainu in Hokkaido is not necessarily accommodated in a single regional populational lineage, the Jomon. The present findings also suggest that admixture between the immigrants from Northeast Asia as represented by the Okhotsk culture people and the indigenous inhabitants in Hokkaido during the 5th–12th centuries AD may in part have contributed to the formation of the physical characteristic of the recent Ainu. In particular, the female Okhotsk culture sample shows closer affinity to the northeastern Hokkaido and the Sakhalin Ainu in some of the analyses presented in this study. Such findings are compatible with those obtained by craniometric analyses, supporting the hypothesis of higher migration rates among females than among males due to patrilocality or the shorter matrilineal generation interval.