Modern Iranian Speaking groups + An ancient Sassanian in Mongolia?

 A short post on the Iranian-speaking groups and their ancestry components.

It is well known that the steppe groups themselves had only a minor genetic impact on the Iranian-speaking groups in Iran and the middle east.

In the rough ancestry modeling of the Balochis, Iranians, and Kurds available on G25, the Bactriana Margiana Archaeological Complex ancestry, (as proxied by the samples from 2000-1500bce Bustan in Uzbekistan) is a common link averaging to 35%. Whereas Steppe ancestry being another common link only averages 13%.

It is important to note that none of the other sources have hidden steppe ancestry (Shahr_Sokhta_BA2 = IVC/Indus Periphery, Kura-Araxes = 4000-2000bce South Caucasus, Ashkelon_LBA = 1500bce Levant ancestry). Bustan_BA = 2200-1600bce BMAC ancestry. BMAC has 0% steppe ancestry itself.

Viktor Sarianidi, the excavator of the main BMAC sites, had famously associated BMAC culture with Zoroastrians given the abundance of fire worship activities (1). While I feel that is a stretch, the evidence is strong that they were proto/Iranian speakers and had an IE culture.

If we replace IVC ancestry with Swat_Iron age ancestry proxied by Katelai_IA, we get the below.

I think we can generally agree that Pakistan_IA sort of ancestry is not the progenitor of the Iranian language family but is more related to the Aryan languages of South Asia. That again leaves the BMAC ancestry as the major common link between the Iranian groups.

Also note the roughly 20-25:80-75 ratio of Steppe:BMAC. I will use it in the next section to make a point.

TUK001: The outlier sample from Xianbei Culture, Mongolia.

This is a very important outlier sample which I guess was missed by most people including me. She is a female and dated to around 300 cal CE. She was a migrant to the Mongolian region. Her ancestry was plublished in the Jeong et al 2020 study.  The paper notes -

Individual TUK001 (250–383 cal. CE), whose burial was an intrusion into an earlier Xiongnu cemetery, has the highest western Eurasian affinity. This ancestry is distinct from that of the Sarmatians and closer to ancient populations with BMAC/Iranian-related ancestry

Elsewhere, the paper notes -

One individual in this study (TUK001) at the site of Tamiryn Ulaan Khoshuu (Burkhan Tolgoi) dates to the era of Xianbei power in Inner Asia; however, there is no cultural context that could affirm affiliation with the Xianbei or other groups of northeastern China. Instead, recent excavations at this site have yielded artifacts, such as pottery from the Kwarezm oasis cultures near the Aral Sea and coins of the Sassanian Persian empire, that indicate significant interactions with areas in Central Asia and much farther west.

The ancestry of TUK001 is something like this

Adding near eastern ancestry reduces the distance (improves fit) further. Confirmation that this woman was indeed a migrant from the modern Iranian region.

TUK001 has mtDNA haplogroup H2a2b, and the ancient DNA database with this haplogroup all belong to either England, Sweden, Germany, Estonia, Czechia, or Poland. The oldest H2a2b samples are from Poland_CordedWare and Czech_Unetice. So we can safely assume that the steppe ancestry in TUK001 is mediated via her mother, while the BMAC related ancestry is via her father.So now we have evidence of a roughly 75:25 bmac:Steppe sample, most likely from the Khwarazm (Chorasmia) or Sassanian Iranian-speaking region existing as late as 300 cal CE. This is a very similar ratio required for the Iranian-speaking modern groups noted above. This sample also disproves Narasimhan et al's 2019 claim that post 1500bce, the Central Asian region had a significant amount of East Asian-related ancestry uniformly present across all groups. 

Modeling Iranian Groups with TUK001 instead of BMAC + Sintashta as sources

TUK001 is a good source for these groups.
*Pashtun_Afg does better with additional Steppe source provided to it.

The overall fit worsens a bit, but TUK001 is a decent source for the ancestry in Iranian groups, and I would bet that this 35% Sassanian/Chorasmian ancestry or a similar ancestry is the common causal link between these Iranian groups, whose genetic roots ultimately lie in the 2200-1700bce BMAC culture.

Thoughts?

Edited to Add:

Let's do a comparison between Aryan groups and Iranian groups.

Aryan groups differ from Iranian in a few ways:

1. Aryan groups have more IVC ancestry than Iranian groups.

2. Iranian groups have significantly more BMAC (Bustan) ancestry than Aryan groups.

3. Iranian groups have significantly more Levant ancestry than Aryan groups who have none. (But we can dismiss this as a source of Iranian languages for obvious reasons).

4. Similar minor levels of Sintashta ancestry in all these groups. (avg 15%).

The almost complete absence of BMAC ancestry in available modern Brahmin groups, but a ~35% presence in Iranian groups points to BMAC ancestry as a possible origin for the Iranian language family.

CONCLUSION:

The null hypothesis that BMAC ancestry is significantly related to Iranian speaking modern groups whereas IVC-like ancestry is significantly related to Aryan speaking modern groups cannot be rejected if a simple t-test is conducted.  The differentiation is so clear that I do not even see a need to conduct such a formal test. Whereas Sintashta related steppe ancestry is equally related to both sets of groups in a lesser proportion.

In my next post, I'll write about the Iran/Armenian origin of Anatolian languages and prove the genetic absence of a steppe link. 

References:

Jeong, C., Wang, K., Wilkin, S., Taylor, W. T. T., Miller, B. K., Bemmann, J. H., et al. (2020). A dynamic 6,000-year genetic history of Eurasia’s eastern steppe. Cell, 183(4), 890-904.e29. doi:10.1016/j.cell.2020.10.015.

Sarianidi, V. (2014). The Indo-Iranian Problem in the Light of the Latest Excavations in Margiana. Studia Orientalia Electronica, 94, 417–442. Retrieved from https://journal.fi/store/article/view/43986