Abstract
In recent years, considerable attention has been paid on the physical characteristics of the Ainu and the Okinawa Islanders in connection with the origin of modern Japanese. In the present study, the metric traits of the dentition in the Tokunoshima Islanders, the Aogashima Islanders, the Okinawa Islanders and the Ainu were compared with each other and with those in the modern populations from Tokyo and Nagasaki, and the Aeneolithic Yayoi population. The first four populations have been isolated or at least nearly isolated for a long period from the populations of main island of Japan because of their geographic conditions.
As regards the shape factors in the dentition, the four isolated populations are closely related to each other, and they show closer affinities to the Tokyo population than to the Nagasaki and the Yayoi populations. The shape factor in the latter two populations shows similar trends but is quite different from that in the other four isolated populations as well as the Tokyo population. Using the principal component analysis method, it is elucidated that the relative size of premolars and incisors plays an important role in difference of the shape factor among the populations. Taking all the results obtained into account, the characteristics of the dentition in the isolated populations are likely under the same genetic control which is common to the Neolithic Jomon population. The origin and affinity of modern Japanese are discussed on the basis of such findings.
