Genetic structure of the Mon-Khmer speaking groups and their affinity to the neighbouring Tai populations in Northern Thailand
- Equal contributors
1 Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
2 Dipartimento di Biologia ed Evoluzione, Universita di Ferrara, Ferrara, Italy
3 Department of Sociology and Anthropology, Faculty of Social Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
4 Department of Laboratory Medicine & Institute for Human Genetics, University of California San Francisco, California, 94143, USA
BMC Genetics 2011, 12:56 doi:10.1186/1471-2156-12-56Published: 15 June 2011
The Mon-Khmer speaking peoples inhabited northern Thailand before the arrival of the Tai speaking people from southern China in the thirteenth century A.D. Historical and anthropological evidence suggests a close relationship between the Mon-Khmer groups and the present day majority northern Thai groups. In this study, mitochondrial and Y-chromosomal DNA polymorphisms in more than 800 volunteers from eight Mon-Khmer and ten Tai speaking populations were investigated to estimate the degree of genetic divergence between these major linguistic groups and their internal structure.
A large fraction of genetic variation is observed within populations (about 80% and 90% for mtDNA and the Y-chromosome, respectively). The genetic divergence between populations is much higher in Mon-Khmer than in Tai speaking groups, especially at the paternally inherited markers. The two major linguistic groups are genetically distinct, but only for a marginal fraction (1 to 2%) of the total genetic variation. Genetic distances between populations correlate with their linguistic differences, whereas the geographic distance does not explain the genetic divergence pattern.
The Mon-Khmer speaking populations in northern Thailand exhibited the genetic divergence among each other and also when compared to Tai speaking peoples. The different drift effects and the post-marital residence patterns between the two linguistic groups are the explanation for a small but significant fraction of the genetic variation pattern within and between them.