Ancient genomes from Southeast Asia (McColl et al. 2018 preprint)

Over at bioRxiv at this LINK. I’m still reading and trying to figure out what the 25 ancient genomes from this preprint say about the peopling of Eurasia and, in particular, South Asian population structure, including the so called Ancestral South Indian (ASI) genetic component. Any ideas? Below are the abstract and Figure 4 from the preprint.

Two distinct population models have been put forward to explain present-day human diversity in Southeast Asia. The first model proposes long-term continuity (Regional Continuity model) while the other suggests two waves of dispersal (Two Layer model). Here, we use whole-genome capture in combination with shotgun sequencing to generate 25 ancient human genome sequences from mainland and island Southeast Asia, and directly test the two competing hypotheses. We find that early genomes from Hoabinhian hunter-gatherer contexts in Laos and Malaysia have genetic affinities with the Onge hunter-gatherers from the Andaman Islands, while Southeast Asian Neolithic farmers have a distinct East Asian genomic ancestry related to present-day Austroasiatic-speaking populations. We also identify two further migratory events, consistent with the expansion of speakers of Austronesian languages into Island Southeast Asia ca. 4 kya, and the expansion by East Asians into northern Vietnam ca. 2 kya. These findings support the Two Layer model for the early peopling of Southeast Asia and highlight the complexities of dispersal patterns from East Asia.

McColl et al., Ancient Genomics Reveals Four Prehistoric Migration Waves into Southeast Asia, bioRxiv, Posted March 8, 2018, doi: https://doi.org/10.1101/278374
Update 10/03/2018: Harvard and friends strike back with their own preprint on the same topic (LINK). Here’s the abstract:

Southeast Asia is home to rich human genetic and linguistic diversity, but the details of past population movements in the region are not well known. Here, we report genome-wide ancient DNA data from thirteen Southeast Asian individuals spanning from the Neolithic period through the Iron Age (4100-1700 years ago). Early agriculturalists from Man Bac in Vietnam possessed a mixture of East Asian (southern Chinese farmer) and deeply diverged eastern Eurasian (hunter-gatherer) ancestry characteristic of Austroasiatic speakers, with similar ancestry as far south as Indonesia providing evidence for an expansive initial spread of Austroasiatic languages. In a striking parallel with Europe, later sites from across the region show closer connections to present-day majority groups, reflecting a second major influx of migrants by the time of the Bronze Age.

Lipson et al., Ancient genomes document multiple waves of migration in Southeast Asian prehistory, bioRxiv, Posted March 10, 2018, doi: https://doi.org/10.1101/279646

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