Extensive ethnolinguistic diversity in Vietnam reflects multiple sources of genetic diversity

Abstract Vietnam features extensive ethnolinguistic diversity and occupies a key position in Mainland Southeast Asia (MSEA). Yet, the genetic diversity of Vietnam remains relatively unexplored, especially with genome-wide data, because previous studies have focused mainly on the majority Kinh group. Here we analyze newly-generated genome-wide SNP data for the Kinh and 21 additional ethnic groups in Vietnam, encompassing all five major language families in MSEA. In addition to analyzing the allele and haplotype sharing within the Vietnamese groups, we incorporate published data from both nearby modern populations and ancient samples for comparison. We find that the Vietnamese ethnolinguistic groups harbor multiple sources of genetic diversity that are associated with heterogeneous ancestry sharing profiles in each language family. However, linguistic diversity does not completely match genetic diversity; there have been extensive interactions between the Hmong-Mien and Tai-Kadai groups, and a likely case of cultural diffusion in which some Austro-Asiatic groups shifted to Austronesian languages. Overall, our results highlight the importance of genome-wide data from dense sampling of ethnolinguistic groups in providing new insights into the genetic diversity and history of an ethnolinguistically-diverse region, such as Vietnam.