2024- Razib Khan on origin of East/Southeast Asian admixture in Bengalis

[okarinaofsteiner]

https://www.brownpundits.com/2024/10/04/...y-burmese/ new genetics blog post from Razib Khan on the East Eurasian ancestry in Bangladeshis

Though Burmese are a good donor for the Tibeto-Burman in Burmese [Bangladeshis?], it seems pretty clear now that I have Tibetan samples that the Bangladeshi samples are a bit more Tibetan-skewed than these Burmese samples. It may be that the early admixture into Bengal was from a Burmese population that had admixed less with the Austro-Asiatic substrate of Burma.

Note that this confirms the Austro-Asiatic populations have a totally different (more southern) East Asian ancestry source.

Anthrogenica user CodenameJungle: "I've been saying this for a while based off of some amateur QpAdm runs I did back in February but the actual Asiatic component in Banglas is way more Tibetic than actual Burmese "

https://www.brownpundits.com/2024/08/27/...-bengalis/

Doing some reading about the Tibetans for a post for my Substack, and I decide to look around and find some Tibetan genotypes. I went back to a question that has come up before, who contributed the East Asian ancestry into Bengalis? Austro-Asiatics or Tibeto-Burmans?

It’s clearly Tibeto-Burmans.

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Spoiler

Looking at the spoilered 3-way admixture plot, Orange seems to be something Yellow River Neolithic related, Green is a "southern" outgroup to Orange and Blue is a non-"Core" East Eurasian outgroup (Hoabinhian, AASI, the West Eurasian component in IVC, Indo-Aryan steppe component, West Eurasian admixture among Northern Han, Para-Papuan among Northern East Asians, etc).

The Bengali samples seem to be 85% Other, 9% YR Neolithic-related, and 6% "southern" on average- so that their East Eurasian ancestry seems to be around a 60-40 mix. By contrast, the East Eurasian ancestry of the Burmese (~85% of their total ancestry) seems to be more like a 40-60 split judging from ~50% of their total ancestry being "southern". Han_North seems more like a 45-55 split, Han_South is split into 25-75 and 17-83 clusters. Vietnamese is more of a 7-92 split in terms of East Eurasian ancestry, Dai is maybe 5-95, and Tibetan is maybe 93-6 the other way. So depending on what exactly Orange and Green represent here, the East Eurasian ancestry among Bengalis is either more "northern East Asia", more "pure Tibeto-Burman" or both.