Friday, March 9, 2018

A Re-Examination of Sundadonty Origin Models

Shannon A. Klainer and G. Richard Scott
AAPA 2018, Meeting Program Abstracts
April 11-14, 2018

Abstract:

The Sinodont and Sundadont dental complexes distinguish East Asians from Southeast Asians. There are two models regarding the origin of Sundadonty: (1) it was a longstanding complex throughout Asia that was ultimately ancestral to the specialized Sinodont complex in northeast Asia; and (2) it arose through gene flow between East Asian Neolithic farmers (Sinodonts) and Austral-Melanesians, the original inhabitants of Southeast Asia. To address these models, frequencies were analyzed for 23 crown and root traits in 15 groups from East Asia, Southeast Asia, Polynesia, Micronesia, and Australia using the Mean Measure of Divergence distance statistic and cluster analysis. Two distinct clusters were found. The first cluster includes four Australian populations, differentiated at a high level from all Asian populations. The second cluster shows two major subclusters: the first contains five East Asian groups, with Japan linked tightly with Mongolia (Urga) and north China (An-yang) while the second includes ten Southeast Asian and Pacific populations. In Japan, modern Japanese exhibit the Sinodont pattern while the ancient Jomon and recent Ainu exhibit Sundadonty. It seems unlikely that the Sundadont pattern was a product of Sinodont X Austral-Melanesian admixture given that the earlier populations of Japan and the widely dispersed populations of the Pacific were all Sundadonts. The pattern of dental variation is more consistent with the idea that Sundadonty is an ancient dental complex in Asia that was ancestral to the Sinodont complex that arose in north Asia during the late Pleistocene.

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