Saturday, June 19, 2010

Chams show closer matrilinear link to Mainland vs. Insular Southeast Asians

 A new study (abstract below) suggests that the Austronesian-speaking Cham people are more closely related in terms of mtDNA to Mainland Southeast Asians as compared to other Austronesian speakers in Island Southeast Asia.

"...our results suggested that the origin of the Cham was likely a process of assimilation of massive local Mon-Khmer populations accompanied with language shift, thus indicating that the Austronesian diffusion in MSEA was mainly mediated by cultural diffusion, at least from the matrilineal genetic perspective, an observation in agreement with the hypothesis of the Nusantao Maritime Trading and Communication Networks (NMTCN)."

Wilhelm Solheim something similar happened in the Neolithic period further north along the coast of Southeast and East Asia, with evidence of the NMTCN turning up at various coastal archaeological sites. However, in this case any linguistic influence either vanished or was submerged as adstrata.
Would be interesting to see what the Y chromosome data reveals about the Chams, who created an ancient kingdom in central Vietnam.

Mol Biol Evol. 2010 May 31. [Epub ahead of print]

Tracing the Austronesian Footprint in Mainland Southeast Asia: A Perspective from Mitochondrial DNA.

State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, P.R. China.

Abstract

As the relic of the ancient Champa Kingdom, the Cham people represent the major Austronesian speakers in Mainland Southeast Asia (MSEA) and their origin is evidently associated with the Austronesian diffusion in MSEA. Hitherto, hypotheses stemming mainly from linguistic and cultural viewpoints on the origin of the Cham people remain a welter of controversies. Among the points of dissension is the muddled issue of whether the Cham people arose from demic or cultural diffusion from the Austronesians. Addressing this issue also helps elucidate the dispersal mode of the Austronesian language. In the present study, we have analyzed mitochondrial DNA (mtDNA) control-region and coding-region sequence variations in 168 Cham and 139 Kinh individuals from Vietnam. Around 77% and 95% matrilineal components in the Chams and the Kinhs, respectively, could be assigned into the defined mtDNA haplogroups. Additionally three common East Eurasian haplogroups B, R9, and M7 account for the majority (>60%) of maternal components in both populations. Entire sequencing of 20 representative mtDNAs selected from the thus far unclassified lineages, together with four new mtDNA genome sequences from Thailand, led to the identification of one new haplogroup M77 and helped to re-evaluate several haplogroups determined previously. Comparing the Chams with other Southeast Asian populations reveals that the Chams had a closer affinity with the Mon-Khmer populations in MSEA than with the Austronesian populations from Island Southeast Asia (ISEA). Further analyses failed to detect the potential homelands of the Chams in ISEA. Therefore, our results suggested that the origin of the Cham was likely a process of assimilation of massive local Mon-Khmer populations accompanied with language shift, thus indicating that the Austronesian diffusion in MSEA was mainly mediated by cultural diffusion, at least from the matrilineal genetic perspective, an observation in agreement with the hypothesis of the Nusantao Maritime Trading and Communication Networks (NMTCN).

Regards,
Paul Kekai Manansala
Sacramento

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