# Population Genetics > Autosomal Genetics >  Iranian Genetics

## Angela

See:
https://journals.plos.org/plosgeneti...l.pgen.1008385

"*Abstract*Iran, despite its size, geographic location and past cultural influence, has largely been a blind spot for human population genetic studies. With only sparse genetic information on the Iranian population available, we pursued its genome-wide and geographic characterization based on 1021 samples from eleven ethnic groups. We show that Iranians, while close to neighboring populations, present distinct genetic variation consistent with long-standing genetic continuity, harbor high heterogeneity and different levels of consanguinity, fall apart into a cluster of similar groups and several admixed ones and have experienced numerous language adoption events in the past. Our findings render Iran an important source for human genetic variation in Western and Central Asia, will guide adequate study sampling and assist the interpretation of putative disease-implicated genetic variation. Given Iran’s internal genetic heterogeneity, future studies will have to consider ethnic affiliations and possible admixture.

*Author summary*Based on genome-wide genotype data on over 1000 samples from eleven ethnic groups present in Iran and by comparison to reference data sets of both extant populations and ancient DNA samples, we show that the Iranian population comprises distinct genetic variation with respect to populations in close geographic proximity, a cluster of genetically largely overlapping ethnic groups as well as a number of strongly admixed groups. These observations, also corroborated by _f3_ migration statistics and other approaches, indicate genetic continuity of and limited influx into the cluster groups over several millennia, despite Iran’s geographic position at a crossroads in West Asia. They also suggest, correspondingly, several instances of language adoption instead of demic replacement in the past. Future human genetic studies, both with a focus on population and medical genetics, will have to consider differences in heterogeneity, consanguinity and degree of admixture between the ethnic groups for an adequate design and interpretation."

The major groups are very close to one another, including the Iranian Arabs, who don't look very Arabic.

"*Seven groups (Iranian Arabs, Azeris, Gilaks, Kurds, Mazanderanis, Lurs and Persians) strongly overlapped in their overall autosomal diversity in an MDS analysis (Fig 1B), suggesting the existence of a Central Iranian Cluster (CIC), notably also including Iranian Arabs and Azeris. The other four groups (Iranian Baluchis, Persian Gulf (PG) Islanders, Sistanis and Turkmen) presented as strongly admixed populations with contributions by different ancestral populations but always with an orientation towards the CIC, being strikingly different from the CIC and from each other, except for Baluchis and Sistanis who partially overlapped (Fig 1A). On a global scale (Fig 2 including “Old World” populations only; see S2 Fig for all 1000G populations), CIC Iranians closely clustered with Europeans, while Iranian Turkmen showed similar yet distinct degrees of admixture compared to other South Asians. The degree was less pronounced for Baluchis, Sistanis and PG Islanders, with the latter showing a pointed orientation towards Sub-Saharan Africans and a co-localization with numerous Latin American samples. Notably, Iranian Arabs now showed some detachment from the CIC towards Sub-Saharan populations.* A local comparison corroborated the distinct genetic diversity of CIC Iranians relative to other geographically close populations [2, 6, 44] (Fig 3 and S3 Fig). Strikingly, the relative genetic location of the Iranian ethnic groups mirrored their geographic location at the nexus between South and Central Asia and West Asia, Northern Africa and the Caucasus. Iranian Baluchis and Sistanis clustered with or nearby Pakistani and other South Asian populations, whereas Iranian Turkmen located next or atop Central Asian populations, respectively. Iranian Arabs appeared distinct from other Arab populations in West Asia and Northern Africa. Furthermore, Zoroastrian samples [6] located as essential CIC members. These results were closely mirrored by the pairwise fixation index (FST) values (Table 2 and S5 Table). CIC groups showed little differentiation (FST~0.0008–0.0033), whereas non-CIC groups consistently yielded much larger values, most extreme for PG Islanders _vs_ Iranian Turkmen (FST = 0.0110). *Still, genetic substructure was much smaller among Iranian groups than in relation to any of the 1000G populations, supporting the view that the CIC groups form a distinct genetic entity, despite internal heterogeneity."

*Some people aren't going to be happy about the following:

" When relating our extant Iranian samples with published ancient DNA (aDNA) samples of different time strata from Iran and beyond to trace temporal-spatial movements of human populations, we did not find indications for substantial migrations into the CIC groups except for Caucasus populations during Neolithic through Bronze Age times (Figs 5–7), with the latter presenting either as a source or as a refuge, i.e. a migration target. In particular, contributions by Steppe people were apparently very limited and restricted to the Bronze Age or briefly before (Fig 6). Overall, the CIC groups appeared to have experienced a largely autochthonous development over at least the past 5,000 years. Remarkably, Early Neolithic Iranian samples [6, 107] from Western Iran and Tappeh Hesar co-localized with the more remotely located extant PG Islanders (Fig 5), whereas later Bronze Age samples from Tappeh Hesar showed a trend towards the CIC (Fig 6), possibly indicating ongoing admixture between these groups. Of note, Central Asian aDNA samples from the Neolithic and the Bronze Age also co-localized with PG Islanders and showed a similar trend (Figs 5 and 6). Sistani samples most distant from the CIC clustered close to Iron Age Pakistani samples (Fig 7) and may have undergone a similar admixture with CIC groups, however, a lack of samples from the past millennia renders this an open question."

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## Anfänger

So there were no steppe people going south into Iran in the Bronze Age ? I don't really understand the authors.

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## Angela

That seems to be what they're saying, or at least that very little moved south, and what little was present is so diluted that it's difficult to find traces of it.

The largest impact seems to be among the PG Islanders, which I don't quite understand. Is it an indication of movement from the east, i.e. Pakistan? Or, perhaps, is it because of the isolation of those islands, and so that is the indicator of the original admixture?

I don't know. I'm not that familiar with possible population movements into Iran, and the authors sort of dropped the ball.

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## Anfänger

I thought those islands are uninhabited or basically arabs from the other side of the gulf lol. There is little know about them in Iranian history except that those islands were once part of the Portuguese Colonial Empire and used as trading centers.

No steppe people in Iran in the Bronze Age. So how did Iranian_Assyrians,Armenians and Iranian_Lurs become R1b-M269 dominant?
Besides that I like the fact that Iranian Arabs are very close to other Iranians. Maybe hatred and discrimination from Iranian Nationalists towards them will stop.

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## Angela

> I thought those islands are uninhabited or basically arabs from the other side of the gulf lol. There is little know about them in Iranian history except that those islands were once part of the Portuguese Colonial Empire and used as trading centers.
> 
> No steppe people in Iran in the Bronze Age. So how did Iranian_Assyrians,Armenians and Iranian_Lurs become R1b-M269 dominant?
> Besides that I like the fact that Iranian Arabs are very close to other Iranians. Maybe hatred and discrimination from Iranian Nationalists towards them will stop.


I don't think they're saying no steppe people. The language changed. They're saying there's very little steppe.

Uniparentals are not good indicators, especially in populations that practice endogamy.

It's not quite the same, but, for example, where my father's family originates almost all the men seem to be U-152. Yet, like all northern Italians, I doubt if their steppe component is more than 25 or so percent, maybe 30% in some cases.

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## Joey37

The larger population there is in an area when the Steppe guys invade, the smaller trace there is of their genes, it appears.

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## Anfänger

> I don't think they're saying no steppe people. The language changed. They're saying there's very little steppe.
> 
> Uniparentals are not good indicators, especially in populations that practice endogamy.
> 
> It's not quite the same, but, for example, where my father's family originates almost all the men seem to be U-152. Yet, like all northern Italians, I doubt if their steppe component is more than 25 or so percent, maybe 30% in some cases.


Sure the language changed but this happened in Iran in Iron Age (about 1200-1000BC). We have historic sources from Assyrians that the Iranian tribes of the Medians,Persians,Parthians all came from the East (Central Asia/South Central Asia). The Persians for example lived in Northern Iran around Lake Urmia before migrating south into Persis. The steppe ancestry those tribes had must have been very low compared to other IE migrations because they had lived in former BMAC regions for 800 to 1000 years. 

Before this Paper I speculated that there was another migration in Early Bronze Age which could have brought the Armenian language and maybe IE Gutian and with them R1b to the western parts of Iran. It could also be that they were very few compared to the advanced agricultral civilizations of the Near East. Anatolia kinda looks the same.

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## MOESAN

I don't know if this could be help but I put it here because I was unaware of these "details" affirmed by Bernard SERGENT (around the 2000's); it could be that the well separated Iranians groups came after these ones who were more ancient there and after a longer contact with BMAC? 

[... The most ancient traces of Indian languages come from documents of Near-East, of the 2nd millenarium BC, which show Indian elements mixed on one side with the Hurrites people, which expanded into the North of the Mesopotamian and Syrian worlds since the 3th millenarium end, on another side with the Kassite people who, from Zagros, invaded the Lower Mesopotamia during the 18th century BC. In the Mitanni empire, founded by the Hurrites, the royal dynasty members wear for a part Hurrite names, for the other part Indian names; among Kassites, the Indians presence is visible through some divinities names. Otherwise, these Indian elements spred until Palestine where the kings wore frequently Indian names ( at the time of the paharaonAmenophis IV, discovered in Tell-el-Amarna (14th Cy))...]


_B. Sergent adds that before it had been supposed these elements were not already Indians, but undifferentiated Indo-Iranians; but the linguistic elements and divinities names confirm a differentiated Indian origin._

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## Angela

Thanks, guys.

Both very helpful posts in figuring this out.

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## nornosh

Could R1b folks were not part of the IE migrations from East and were native to the region since Neolithic as remains of the group of PIEs which didn't settle Pontic steppe.

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## jack456

Based on genome-wide genotype data on over 1000 samples from eleven ethnic groups present in Iran and by comparison to reference data sets of both extant populations and ancient DNA samples.

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