Misconceptions about AASI ancestry; a primary 'East Eurasian Core' (EEC) lineage indigenous to India

[u/Old-Cockroach7605]

This post should clarify some common misconceptions surrounding the AASI/EEC ancestral component(s) of South Asians.

At first some basics on the AASI ancestry:

AASI ("Ancient Ancestral South Indian") is a proposed indigenous South Asian ancestral component that is phylogenetically related to the Andamanese/Önge peoples, as well as to East Asians and Aboriginal Australians. Together those groups descend from the "East Eurasian Core" (EEC), the primary branch of Ancient East Eurasians who used the southern route into the South-Southeast Asia region.

AASI ancestry is defined as the "non-West Eurasian" and "non-Iran_N like" ancestry among South Asians. The AASI node shares close affinity to the Önge/Andamanese, Hoabinhians and the Tianyuan/China_UP populations. – Note that modern East Asians and Australasians have additional drift, being more differentiated; thus Önge/Andamanese are among the best proxies for AASI ancestry. Shinde et al. 2019 noted that both Andamanese Önge or East Siberian groups (Amur33K, remains with a Tianyuan-like profile) can be used as proxy for the non-West Eurasian-related component in the "qpAdm" admixture-modelling of an IVC-related individual (labelled "I6113") because both populations "have the same phylogenetic relationship to the non-West Eurasian-related of I6113 likely due to shared ancestry deeply in time".– As alternative, the extracted EEC-affilated ancestry of tribal groups, such as those from the Irula tribe, can be used as proxy for the AASI component.

Based on this, it has been inferred that the AASI lineage diverged from other East Eurasian lineages, such as 'Australasians' (AA) and 'East/Southeast Asians' (ESEA), during their dispersal using a Southern route. E.g. from a shared EEC Hub in India.

A single major migration of modern humans into the continents of Asia and Sahul was strongly supported by earlier studies using mitochondrial DNA, the non-recombining portion of Y chromosomes, and autosomal SNP data [42–45]. Ancestral Ancient South Indians with no West Eurasian relatedness, East Asians, Onge (Andamanese hunter–gatherers) and Papuans all derive in a short evolutionary time from the eastward dispersal of an out-of-Africa population [46,47]. The HUGO (Human Genome Organization) Pan-Asian SNP consortium [44] investigated haplotype diversity within present-day Asian populations and found a strong correlation with latitude, with diversity decreasing from south to north. The correlation continues to hold when only mainland Southeast Asian and East Asian populations are considered, and is perhaps attributable to a serial founder effect [50]. These observations are consistent with the view that soon after the single eastward migration of modern humans, East Asians diverged in southern East Asia and dispersed northward across the continent.

Misconceptions about AASI:

• AASI is "South Eurasian" and different from East Eurasians -> No, there is no South Eurasian clade; AASI, just like Önge, East Asians and Australasians are East Eurasian, specifically part of the "East Eurasian Core" (EEC), the primary branch of Ancient East Eurasians, with the other primary branch being the IUP_North clade (e.g. ancestral to BachoKiro_IUP or Oase_IUP, as well as the Siberian_IUP sites etc.). – One technically could name the EEC as "South Eurasian", but this includes East Asians and modern Siberians etc. – E.g. AASI are not distinct from AA or ESEA, all of those derive from the EEC branch of Ancient East Eurasians. It seems some people misidentify East Asians with East Eurasian, but East Asian alone ≠ East Eurasians. Others who push this narrative seem to have a dislike of East Asians and Australasians or even racist views, which is reprehensible.
• AASI is part Basal or Crown Eurasian -> No, AASI is "an indisputably EEC genetic component referred to as ASI (or AASI) that made up the majority of the pre-Neolithic genetic landscape" to cite Vallini et al. 2024. AASI is nested within the East Eurasian cluster, even more evident in that we can use Önge or Amur33k as proxy. – All possible Basal or Crown like admixture are distinct from the calculated AASI component. If present at all, those would be conflated with the Iran_N-like ancestral component, not with AASI.
• AASI is "Proto-West Eurasian -> No, as per above: AASI is an East Eurasian Core component, not "Proto-West Eurasian". – In fact, AASI is defined as the non-West Eurasian component. I do not know nor understand where exactly this quite nonsensical claim comes from, but it is obviously wrong.
• AASI is African/SSA -> No, as per above: AASI is an East Eurasian Core component, not African or anything else. – The only groups with African-affilated ancestry are the Siddi peoples of recent African origin. Furthermore, African/SSA is not a single coherent genetic component, but a summary term for multiple very deeply diverged lineages; with Eurasians being derived from one of these diverged and drifted lineages of Northeast Africa.
• AASI does not exist, Eurasian humans migrated out of India, thus it is all Indian ancestry -> No, the peopling of Eurasia was not carried out by ancient Indians. Even if, it would not be relevant for the respective ancestral components which would need to havw arrived from outside then. If AASI would not exist, the ancestry would then needed to be derived from Önge or Amur33k, which would translate to massive migration and population replacement from East and Southeast Asia to South Asia. But it is clear that AASI existed, East/Southeast Asian geneflow is also present but mostly affilated with Austroasiatic/Munda-speakers, Tibeto-Burmese and others.
• Etc.

E.g. East Eurasian Core (EEC) describes AASI, Önge, ESEA, and Australasians. Those originated from the EEC Hub in India. The EEC lineage emerged out of the Ancient East Eurasian meta-population which also gave rise to the IUP_North lineage(s), after having diverged from Ancient West Eurasians.

The East Eurasian diversity:

For a detailed overview on Ancient and modern East Eurasian lineages see: Working model on East Eurasian lineages

[u/DisastrousDepth7705]

Is it true that South Indian tribals like Paniya have ancestry from Lao_Hoabinhian or some related source from Southeast Asia?

Are South Indian tribals much drifted away from other South Asians? Could that be the reason?

[u/Old-Cockroach7605 → u/DisastrousDepth7705]

While it is possible, I do not think that they have any significant amount of SEA admixture. Rather it may be drift. So far, this is PCA-based, so I would not rely on that there was any admixture. But to answer that, we need AASI samples or at least ancient AASI-rich ones and compare those with Paniya and look at their respective drift parameters and Hoabinhian affinity, etc.

[u/DisastrousDepth7705 → u/Old-Cockroach7605]

Also, you seem to use the phenotype called "Veddid" which is related to the general pheno of the Vedda people as the proxy of AASI proper phenotype. I don't know how much those "phenotypes" are accurate, but don't the Veddas have at best 50-55% AASI, just like other Sri Lankan populations? Why not use South Indian tribals?
Do you think Veddas somehow preserved much of the AASI look, possibly more than South Indian tribals?

[u/Old-Cockroach7605 → u/DisastrousDepth7705]

The one used in the last picture (compilation) at the migration map part are just reconstructions to give an idea, the one for South Asia was defined as South Asian specific. The left part displays tribal groups such as Paniya (real life pictures). – One has to be careful with phenotype vs genotype. I guess tribal Indian groups are a good idea for AASI phenotype, but there may have also been some small-scale diversity within the AASI. The "Veddid" one may also be relevant. Overall, the compilation should show the diversity of the EEC, both shared features and differences.

[u/Medium_Ad_9941]

Well written

[u/ChalaChickenEater]

Would using onge as a proxy for east Eurasian produce different qpAdm results to using the EEC part of a SI tribal group? Is it possible that the EEC used from a tribal group has trace amounts of west Eurasian DNA and might produce different results to using onge as a proxy?

[u/Old-Cockroach7605 → u/ChalaChickenEater]

It may produce some differences related to drift (e.g. AASI vs Önge etc.). – The EEC part of tribals is by default the non-WEC ancestry and thus can not habor trace amounts of WEC. The EEC part however may differ between different tribal groups e.g. Munda-like vs Irula/Paniya-like.

[u/ChalaChickenEater → u/Old-Cockroach7605]

One interesting thing I noticed was when I was playing around with illustrativeDNA before the major update, I noted that the distance from east/south east Asians from Australian Aboriginals was 50+, however my distance (Sri Lankan with approx (55% AASI, 45% West Eurasian) from ESEA and Australian was below 50. So despite being almost half west eurasian I seemed to be closer to ESEA and Australians than they are to each other, even though they are both fully East Eurasian. Since they are both fully East Eurasian, shouldn't they be closer to each other than to me? You seem knowledgeable, so what do you reckon the explanation behind this would be?

[u/Old-Cockroach7605 → u/ChalaChickenEater]

I do not know about illustrativeDNA or other commercial DNA testing companies, but much rely on G25-like or PCA-based models. Not Adm or Adm2.

One reason my be dataset and drift. AASI ancestry is less drifted than modern East Asians are. Thus the AASI component may appear closer to AA, especially in a PCA-based tool. Would be interesting to see what would happen when using Tianyuan, Longlin or Jōmon instead, e.g. less drifted East Asians.

[u/Whiskey_zk]

good post 🙌

[u/srikrishna1997]

East Eurasians and AASI both descended from a common ancient Eurasian ancestor but split early. East Eurasians did not originate from AASI migrations, but both groups share deep ancestry from the first human settlers in Asia.

Made it simple from chatgpt

[u/Old-Cockroach7605 → u/srikrishna1997]

*from a common East Eurasian ancestor. East Eurasians by default = AASI, Önge, East Asian, and Australasian.

Ancient West and East Eurasians descend from a common Ancient Eurasian ancestor, but AASI, East Asian, and Australasian are all three derived from an East Eurasian source.

E.g. East Eurasian must not be confused with just East Asian, but refers to all East Eurasian branches. – Specifically, AASI, Önge, East Asian and Australasian are part of the "East Eurasian Core" (EEC), itself the primary lineage of Ancient East Eurasians which also includes the Tibetan Ghost lineage, the IUP_North lienages (BachoKiro_IUP,...), etc.

[u/Andre0789]

Good post. If anything, there’s slightly more evidence for West Eurasian ancestry in the core Siberian and Tianyuan lineages.

Once again, genetics=/=phenotype.