Distribution of Group-Specific Component/Vitamin D-Binding Protein Alleles in Southwestern Japan and Geographical Clines of Allele Frequencies in Japanese Populations.

Twenty-four non-metric tooth crown traits of Miyako and Ishigaki Islanders, from the southernmost Ryukyu Islands, were investigated and compared with those of neighboring populations. The frequency of double-shoveling in Sakishima samples, and especially, Ishigaki Island, is lower than that found among Atayal people (Taiwan) and main-island Japanese. The frequencies of protostylid and cusp 6 in Miyako and Ishigaki Islanders are comparable to those in Hokkaido Ainu and lower than in main-island Japanese and Atayal. Miyako and Ishigaki Islanders, as well as other Ryukyuans, are basically more similar to main-island Japanese than to Ainu, while being situated between main-island Japanese and Ainu in terms of both mean measure of divergence (MMD) and R-matrix methods. However, Ishigaki and Miyako Islanders are relatively close to Hokkaido Ainu among Ryukyu people and main-island Japanese, as suggested in some previous preliminary studies. The estimated Fst (the ratio of among-group variation to total variation), using an average heritability rate = 0.55 for the non-metric tooth crown traits used in this study, displayed low levels of interregional variation, as already indicated in analyses of genetic, cranial and dental metric data. Meanwhile, the relatively large diversity of Ryukyu Islanders based on Fst suggested long-term isolation or poor intra-island contact among the Ryukyu Islands. The lower observed variation compared with the expected variation in most Ryukyu samples may reflect a greater degree of genetic drift in the Ryukyu Island chain.

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Non-metric dental variation of Sakishima Islanders, Okinawa, Japan: a comparative study among Sakishima and neighboring populations

Haneji

Hanihara

Sunakawa

et al. 2007

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Metric dental diversity of Ryukyu Islanders: a comparative study among Ryukyu and other Asian populations

Toma

Hanihara

Sunakawa

et al. 2007

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Mesiodistal and buccolingual crown diameters were examined to describe and compare patterns of metric dental variation in five modern samples from the Ryukyu Island chain (Miyako, Ishigaki, Tokunoshima, and two samples from Okinawa Island). Principal component analysis applied to two separate datasets, raw measurement and standardized (C-score) data, for 32 Asian and Pacific samples, including the five Ryukyu Islander series, produced an overall size factor and three shape factors (relative size of mesiodistal diameters versus buccolingual diameters and two kinds of front-back polarity). Ryukyu Islanders have similar crown dimensions as those of the predominant eastern Asian groups, characterized by mesodont dentition. In terms of shape factors, Ryukyu Islanders are distinctive among eastern Asian population groups on the one hand, and show diversity among themselves on the other hand. The inter-regional variation of Ryukyu Island groups estimated by F st falls within the range of 4-6% of the total variance, which is greater than those of Arctic population samples (Aleuts and Eskimos). The average within-group variance of the Ryukyu Island series measured by the R-matrix method (intra-regional variation) is compatible with those of East and Northeast Asians, Micronesians, and Polynesians. These findings suggest that differential patterns of long-term gene flow from an outside source, geographical isolation, and genetic drift in each island of the Ryukyu Island chain has produced the morphological diversification of modern Ryukyu Islanders.

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Distribution of Group-Specific Component/Vitamin D-Binding Protein Alleles in Southwestern Japan and Geographical Clines of Allele Frequencies in Japanese Populations.

Cited by 2 publications

References 23 publications

Non-metric dental variation of Sakishima Islanders, Okinawa, Japan: a comparative study among Sakishima and neighboring populations

Non-metric dental variation of Sakishima Islanders, Okinawa, Japan: a comparative study among Sakishima and neighboring populations

Metric dental diversity of Ryukyu Islanders: a comparative study among Ryukyu and other Asian populations

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