Both Razib and Dienekes have reviewed a paper on the population genetics of Central Asian peoples. To make sense of Central Asian ancestry has been challenging, to say the least. In particular, the problem is compounded by nomadic peoples without much written history nor uncovered archaeological record.
Ethnicities of Central Asia
What we do have are the linguistic, physical features, and now because of this paper some of the allelic traits of the different populations. Razib has pointed out some strange phrases from the paper that make me wonder about how much background on Central Asian cultures, migrations and phenotypes the authors really knew before publishing. There is really no confusion that more western Central Asian people look more western while more eastern Central Asian people look eastern, with some but little, shared traits. But I don’t put total blame on them for not doing their research, it’s hard to make sense of the ancestry of Central Asia.
Razib has done a nice job explaining some of the previous cultures. Do check his post out. But a quick introduction for those who want to know, the steppes of Central Asia during the pre-Islamic periods, were predominated by sedentary Iranian peoples like the Sogdians, Chorasmians, Scythians, and Alans. Between the 5th-10th century, Turkic peoples moved from the east through the west. Turkic is a name given to a group of people who share a linguistic ancestry, Altaic. Some of these groups you may know are the Uyghur and Tatars. The Hun are possibly Turkic. Another major Altaic, but not Turkic, migration occurred with the Mongols during the 13th century.
There has been some confusion regarding the folklore and historical record compared to the phenotypic and linguistic differences on just how impactful the Turkic replacement been. The western historical record indicates that the invading Hun of the 5th centuries and Mongols later made a significant impact, wiping out large portions of ancient ethnic Iranian populations. This understanding is both true and false. There is evidence of entire cities being destroyed. At the same time, in texts like Ghenghis Khan and the Making of the Modern World, you read statements on how the Altaic invasions was much less of a violent horde and was demonized because of their comparative weakness in written language. In other words, the captors of the Mongolian Empire wrote their account of their overlords.
To this day, this has lead to “nationalistic” and ethnic conflicts and confusion, as evidenced by the June massacres of the Uzbeks by Kyrgyz groups regarding ancestry and heritage. The general consensus is the Tajik and Uzbeks were once a majority Indo-European-speaking population that were assimilated by migrating Turkic-speaking groups. The divergence from Middle Iranian to Turkic and New Persian was predominantly the result of an elite dominance process, as Razib points out.
So, just to which ancestry do Tajiks and Uzbeks, who share a Indo-Iranian language family and the Karakalpaks, Kazaks, and Turkmen, who share a Turkic language family belong to? With a 1,500 year shared regional history but linguistic separation, is it possible to flesh out if Turkic people invaded the West and replaced populations, or was there a back flow of Westerners who moved east?
Geographic-Linguistic-Genetic location of 26 Central Asian populations
The results from the paper out in The European Journal of Human Genetics, indicate that,
“The analysis of genetic variation reveals that Central Asian diversity is mainly shaped by linguistic affiliation, with Turkic-speaking populations forming a cluster more closely related to East-Asian populations and Indo-Iranian speakers forming a cluster closer to Western Eurasians. “
STRUCTURE plot on Central Asian Populations
Dieneke points out how the STRUCTURE plot (above) lets us see the that eastern Hazaras and Uyghurs have remained relatively separate from the more western peoples. Furthermore, supplemented by Razib’s comment,
“The eastern Turkic groups seem the least impacted by the Iranian substrate which was dominant before the arrival of Turks, while the Turcoman group sampled from western Uzbekistan seems to have been the most genetically “Iranized.”
…the correspondence analysis shows the Turkic groups exhibited a linear distribution toward East Asia, while the Iranian ones were placed where you’d expect them geographically.”
The data from this paper indicates that Turkic people did in fact move west, especially the men, since there’s high degree of genetic homogeneity on the Y chromosomal lineage. They remained more genetic and linguistically unified and did not assimilate into Iranian genetics and languages. Additionally, contrary to popular belief, they did not absorb large populations of Iranians as their genetics and languages remained more separate than integrate.
A disclaimer, this is but one paper, with limitations on the number allelic markers that would make fine population differences more noticeable. But we can still see large trends regarding the ancestry of Central Asian people.
Martínez-Cruz B, Vitalis R, Ségurel L, Austerlitz F, Georges M, Théry S, Quintana-Murci L, Hegay T, Aldashev A, Nasyrova F, & Heyer E (2010). In the heartland of Eurasia: the multilocus genetic landscape of Central Asian populations. European journal of human genetics : EJHG PMID: 20823912