Mitochondrial DNA-HVR1 Variation Reveals Genetic Heterogeneity in Thai-Isan Peoples from the Lower Region of Northeastern Thailand

摘要

The Thai-Isan are the largest ethnic group in Northeastern Thailand, who migrated from the territory of present-day Laos around 200 years ago. There are a limited number of previous studies of mtDNA diversity in Northeastern Thai populations. The present study investigates genetic variation and genetic structure in three Thai-Isan populations by analyzing mitochondrial DNA variation in hypervariable region 1. We also evaluate genetic relationship and admixture between Thai-Isan and surrounding populations from Northeastern Thailand, and neighboring countries. The studied Thai-Isan populations reveal genetic differentiation from each other and from compared populations. Thai-Isan exhibit a close relationship with surrounding populations, particularly the Lao and Khmer, reflecting extensive gene flow among them. Admixture proportions observed in most Thai-Isan populations exhibit a higher contribution from the parental Lao than the Khmer. Different admixture patterns reflect genetic heterogeneity of Thai-Isan groups. The lower the latitude, the higher the Khmer contribution might be associated with the ethnic constitution of parental populations in each Thai-Isan population. More genetic data from HVR2 and coding regions, as well as different marker systems are needed to infer population history of Thai-Isan populations.