title: Genetic structure of the Mon-Khmer speaking groups and their affinity to the neighbouring Tai populations in Northern Thailand.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Wibhu
authors.initials: W
authors.lastname: Kutanan
authors.forename: Jatupol
authors.initials: J
authors.lastname: Kampuansai
authors.forename: Silvia
authors.initials: S
authors.lastname: Fuselli
authors.forename: Supaporn
authors.initials: S
authors.lastname: Nakbunlung
authors.forename: Mark
authors.initials: M
authors.lastname: Seielstad
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bertorelle
authors.forename: Daoroong
authors.initials: D
authors.lastname: Kangwanpong
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D041322:Chromosomes, Human, Y / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D056426:Genetic Loci; D005828:Genetics, Population / Q000379:methods; D005838:Genotype; D006801:Humans; D007802:Language; D008297:Male; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D044382:Population Groups / Q000235:genetics*; D013785:Thailand / Q000208:ethnology
chemical_list: D004272:DNA, Mitochondrial