Indian cultural influence is remarkable in present-day Mainland Southeast Asia (MSEA), and it may have stimulated early state formation in the region. Various present-day populations in MSEA harbor a low level of South Asian ancestry, but previous studies failed to detect such ancestry in any ancient individual from MSEA. In this study, we discovered a substantial level of South Asian admixture (ca. 40% – 50%) in a Protohistoric individual from the Vat Komnou cemetery at the Angkor Borei site in Cambodia. The location and direct radiocarbon dating result on the human bone (95% confidence interval is 78 – 234 calCE) indicate that this individual lived during the early period of Funan, one of the earliest states in MSEA, which shows that the South Asian gene flow to Cambodia started about a millennium earlier than indicated by previous published results of genetic dating relying on present-day populations. Plausible proxies for the South Asian ancestry source in this individual are present-day populations in Southern India, and the individual shares more genetic drift with present-day Cambodians than with most present-day East and Southeast Asian populations.
No surprise to readers of this weblog. South Asians obsess about possible admixture/contact with West Asia and Europe for obvious reasons, but it’s been pretty clear for a while that the “Indian cultural influence” on Southeast Asia was also demographic. Mainland Southeast Asia and the western part of Maritime Southeast Asia have minor but consistent levels of Indian ancestry. It showed up decades ago in Cambodian males who carried R1a Y haplogroup. And it showed up in a 2012 methods paper that detected gene flow from Pakistanis to Cambodians (no Indian samples in the dataset):
Genetics is basically done now. You can observe, for example, that lowland Thai populations have Indian ancestry, while highland tribes don’t have it.
We now know that the influence of Indian culture of a southern flavor to Southeast Asia was mediated by large numbers of humans. Indian genetic imprint on Burma can be chalked up to being Bengal’s neighbor, but you can’t say the same about Cambodia or Bali. Who were these people? Well, in a way, you could say that they were the “Brown Rajahs” for ancient Sarawak…