中国ダフル族の歯の形質人類学的研究

抄録

Tooth crown traits of the Dafurs of Inner Mongoria province, China, were examined and compared with 23 East Asian populations in order to clarify the anthropological position of the Dafurs based on Mongoloid dental variation. Plaster models were taken from 92 male and 98 female students, 16 to 19 years of age, of the Dafurs tribe middle high school in Hailaer. Nineteen non-metric traits of tooth crown were classified using the Arizona State University dental anthropological system and counted with the individual count method.
The frequencies of 19 traits in the Dafurs were compared with those of 23 East Asian populations. Ten crown traits that indicated high frequencies were Shoveling (UI1), Double shovel (UI1), Canine medial ridge (UC), Cannine distal accessory ridge (UC), Premolar lingual cusp variation (LP2), Protosylid (LM1), Deflecting wrinkle (LM1), Cusp 6 (LM1), Cusp 7 (LM1) and 4 cusp (LM2). Those showing low frequencies were Winging (UI1²), Interruption groove (UI2), Tuberculum dentale (UI2), Odontome (UandL 1, 2), Hypocone (UM2), Cusp 5 (UM1), Carabelli's trait (UM1), Distal trigonid crest (UM1) and Y-groove pattern (LM2).
On comparing the eight crown traits that indicated significant differences between Sinodonty which is typical of Northeast Asia, and Sundadonty which is typical of Southeast Asia, the Dafurs had six Sinodont-like traits: Shoveling, Double-shovel, Carabelli's trait, Cusp 5, Deflective wrinkle and Y-groove pattern, and two Sundadont-like traits: Winging and 4 Cusp.
Two major clusters were obtained from a cluster analysis on the Ward method among 23 East Asian populations and the Dafurs, based 19 crown traits. One was Sinodonty cluster, and the other Sundodonty cluster. The Dafurs was included in the Sinodonty cluster. The Sinodonty cluster was divided into two subclusters, one was the Han and Japanese group, and the other the Chaoxian and the Man group. The Dafurs was included in the latter.
Furthermore, the multidimensional scaling analysis showed that the Dafurs was closest to the Chaoxian and the Man, and nearest to Sundadonty as contrasted with typical Sinodonty.
Judging from the above analyses, it was proved that the dentition of the Dafurs was charasteristic of both Sinodonty and Sunndadonty, and the Dafurs was the closest to the Chaoxian and the Man in the East Asian Mongoloid populations.