Characteristics of dental morphology in the Xinjiang Uyghurs and correlation with the EDARV370A variant.

Teeth are one of the most important materials for anthropological studies because they are likely to be preserved in ancient remains. While the frequencies of dental characteristics can provide clues to the phylogeny of populations, genetic studies at the individual level can further reveal the biological mechanisms and evolutionary context of dental characteristics. In this study, by analyzing 38 dental characteristics of 242 Xinjiang Uyghur individuals, we found that (i) the dental characteristics of the Uyghurs showed evidence of admixture between European and East Asian populations. The admixture proportions were in line with those previously reported in population genetic studies; (ii) the Xinjiang Uyghur dental characteristics formed three clusters in pairwise correlation analysis. One of the main clusters consisted of characteristics including incisor shoveling, double shoveling and mesial ridge; and (iii) all the characteristics in this cluster were significantly correlated with the genetic variant EDARV370A. The extracted composite phenotypic factor was also significantly associated with EDARV370A, which explained 18% of the total phenotypic variance. This indicated a pleiotropic effect, i.e., the same genetic factor affects a number of dental characteristics at the same time. Our results confirmed that EDARV370A, a genetic variant that first originated in East Asia about 30000 years ago, played an important role in incisor shoveling in East Asia. This finding suggested that incisor shoveling in modern humans in East Asia is likely to have appeared after the late Pleistocene.