Temporal craniometric changes from the Jomon to the Modern period in western Japan

Temporal changes in morphometric features of human cranial remains from the late Jomon period (1500 B.C.-300 B.C.) to the Modern period (1900-1950 A.D.) in western Japan are examined. The results of univariate and multivariate analysis indicate that the Yayoi people (300 B.C.-300 A.D.), characterized by high faces and tall stature, show morphological discontinuity with the earlier Jomon people, who exhibit lower faces and shorter stature. This discontinuity contrasts with the relatively continuous changes among populations after the Yayoi. Comparing these changes with those documented in the Kanto region of eastern Japan indicates there are significant regional differences in the degree and rate of transformation in certain cranial features, especially facial height, between the two regions. Differences in cranial shape between the two regions become apparent during the Yayoi period and these differences tend to diminish thereafter. The most plausible explanation for these observed changes is the introduction of new genes, coinciding with the arrival of new immigrants from the Asian continent in the northern Kyushu-Yamaguchi region at the beginning of the Yayoi period. Further testing of this hypothesis will be necessary before definitive conclusions can be reached regarding the appearance of modern Japanese.