Yamnaya isn’t from Iran just like R1a isn’t from India

A strange thing sometimes happens in population genetics: highly capable and experienced researches come up with stupid ideas and push them so hard that, despite all the evidence to the contrary, they become accepted as truths. At least for a little while.
It’s obvious now, thanks to full genome sequencing and ancient DNA, that Y-chromosome haplogroup R1a cannot be native to India. It arrived there rather recently from the Eurasian steppe, in all likelihood during the Bronze Age, probably as the Indus Valley Civilization (IVC) was collapsing or, perhaps, just after it had collapsed.
But for quite a few years this was something of a taboo, even politically incorrect, narrative, and it was vehemently rubbished by many Indians, including Indian scientists, and their western academic sympathizers.
Indeed, a whole series of papers came out, often in high brow scientific journals, claiming that R1a originated in South Asia, and that it spread from there to Europe. This, it was also claimed, was the final nail in the coffin of the so called Aryan Invasion Theory (AIT), because R1a was often described as the “Aryan” haplogroup.
I wasn’t impressed by any of this nonsense. I said so here and elsewhere, to the great annoyance of those who believed, against all reason and logic, that the Indo-Aryans, and even Indo-Europeans, were indigenous to India. Here’s a taste of some of my work on the topic going back to 2013.

South Asian R1a in the 1000 Genomes Project
Children of the Divine Twins
The Poltavka outlier

Looking back, it’s all a bit rough, but very cool nonetheless. However, I was often accused of being biased, unscientific and even bigoted and racist as a result of offering such commentary and research. Make no mistake, my detractors were seething that I would dare to question what was apparently a scientific reality, and they wanted to shut me up. It was a nasty experience, but it now feels great to be vindicated.
Nowadays, no objective person who, more or less, knows their stuff would argue that the vast majority of the R1a in India doesn’t ultimately derive from the Pontic-Caspian steppe in Eastern Europe.
But otherwise things haven’t changed all that much in the last few years. For instance, despite a whole heap of ancient DNA data being available from Eastern Europe and West Asia, there’s a widely accepted idea that the Early Bronze Age (EBA) Yamnaya culture formed on the Pontic-Caspian steppe as a result of migrations from what is now Iran.
This is not true. It can’t be true, because it’s contradicted by all of the data. I’ve tried to explain this every time new data streamed in, but generally to no avail.

Yamnaya =/= Eastern Hunter-Gatherers + Iran Chalcolithic
Another look at the genetic structure of Yamnaya
Likely Yamnaya incursion(s) into Northwestern Iran

Thus, the Yamnaya people and culture were indigenous to Eastern Europe, and basically formed as a result of the amalgamation of at least three different populations closely related to Eastern European Hunter-Gatherers (EHG), Caucasus Hunter-Gatherers (CHG), Early European Farmers (EEF) and Western European Hunter-Gatherers (WHG). They did not harbor any significant ancestry from what is now Iran; at least not from within any reasonable time frame.
However, me communicating this fact has resulted in some rather strange and unsavory reactions from a number of individuals who appear to have a big emotional investment in this issue. They become frustrated and even angry when I try to explain to them that there’s no sense in looking for the genetic origins of Yamnaya in Iran, much like the people who argued with me when I tried to reason with them that R1a wasn’t native to India. Here’s an example from a recent blog post (for the full conversation scroll down to the comments here).

Heh, here we go again with the accusations of bias, scientific impropriety and whatnot. Ironically, the poor chap just couldn’t comprehend that he never had an argument to begin with, quite obviously due to his own bias in regards to this topic. Well, at least he didn’t call me a racist.
In a recent preprint, Wang et al. correctly characterized Yamnaya as, by and large, a mixture of populations closely related to EHG, CHG, EEF and WHG (see here), with no obvious input from what is now Iran. Sounds familiar, right?
They also discovered that, during the Chalcolithic and Bronze Age, the Caucasus and nearby steppes were mainly home to three quite distinct populations: 1) Steppe groups, including Eneolithic steppe and Caucasus Yamnaya, 2) Caucasus groups, including Kura-Araxes and Maykop, and 3) Steppe Maykop, which they classified as part of 1. These populations were all separated by clear genetic and cultural borders, with significant and unambiguous mixture from the Caucasus cluster only in a couple of Steppe Maykop outliers and one Yamnaya outlier from what is now Ukraine.
Clearly, this leaves no room for any migrations from what is now Iran to the steppe that would potentially give rise to Yamnaya. In other words, the main genetic ingredients for what was to become Yamnaya were already on the steppe well before Yamnaya, during the Eneolithic, and it’s quite likely that they were indigenous to the region.
However, interestingly, Wang et al. did appear to try to save the link between Yamnaya and Iran by constantly referring to the CHG-related ancestry in Yamnaya as “CHG/Iranian”. I’m not surprised because most of these authors are associated with the Max Planck Institute for the Science of Human History (MPI-SHH), which is currently pushing a proposal that the Proto-Indo-European (PIE) homeland was located in what is now Iran and surrounds (see here). So, obviously, they need to somehow show a relationship between Yamnaya and Iran, because Yamnaya and the closely related Corded Ware archaeological complex are generally seen as early Indo-European cultural horizons. Good luck with that.
Actually, let me make it clear once and for all that I couldn’t care less where the very first Indo-European words were uttered. It’s just something that I find interesting. I rather doubt that this was within the borders of present-day Iran, and I explained in some detail why in a post almost two years ago (see here). But if someone manages to prove that the PIE homeland was indeed located partly of wholly within what is now Iran, that’s OK. I will not be emotionally traumatized as a result.
However, obviously, this will have to be done with the assumption in mind that Yamnaya and Corded Ware became Indo-European-speaking purely via an linguistic transmission, with hardly any associated gene flow. It’s possible, I guess. But then there’s almost 200 years of scholarship based on linguistics and archaeological data that generally agrees in favor of the Pontic-Caspian steppe as the PIE homeland.
On a related note, I also couldn’t care less whether the Aryan Invasion Theory (AIT) reflects what really happened during the Indo-Europeanization of South Asia, or if it’s more appropriate to call it the Aryan Migration Theory (AMT). I’ll accept whatever an objective analysis of all of the relevant data shows when we have enough of it to make an informed decision.
However, currently, I see nothing in the data that would prevent the AIT from being true. To me, the profound impact that the Bronze Age steppe peoples obviously had on South Asia, and especially on the Indo-European-speaking Indian upper castes, suggests that, overall, an invasion-like scenario is quite plausible. But I might be wrong, and so what if I am?

Of horses and men

Y-HT-1 is today by far the most common Y-chromosome haplogroup in domesticated horse breeds. According to Wutke et al. 2018, this is probably the result of artificial, human induced selection for this lineage, initially on the Eurasian steppe during the Iron Age, and then subsequently in Europe during the Roman period (see here).
However, during the Bronze and Iron Ages, before Y-HT-1 reached fixation, another very important Y-haplogroup in domesticated horses was its older sister clade Y-HT-4.
Indeed, it’s likely that both Y-HT-1 and Y-HT-4 first dominated the domesticated horse gene pool during the Bronze Age, probably because they happened to have been present in the horse population exploited by the early Indo-Europeans. This was missed, or at least not directly discussed by Wutke et al., but I’d say it’s a fairly obvious conclusion that can be drawn from their data, especially if we consider the fact that horses are the most important animal in the Indo-European pantheon.
Thus, the story of Y-HT-1 and, up to a point, Y-HT-4 is probably very similar to that of two human Y-haplogroups, R1a-M417 and R1b-M269. Both of these lineages also rose to prominence rather suddenly during the Eneolithic and Bronze Age, in all likelihood because they were present amongst early Indo-European-speaking males (see here).
Below is a map of the earliest reliably called and dated instances of Y-HT-1, Y-HT-4, R1a-M417 and R1b-M269 in the ancient DNA record. Not surprisingly, all of the points on the map are located on or very close to the Pontic-Caspian steppe, which is generally accepted to have been the Proto-Indo-European homeland. Fascinating stuff.

See also…
Central Asia as the PIE urheimat? Forget it
Cultural hitchhiking and competition between patrilineal kin groups may have led to the post-Neolithic Y-chromosome bottleneck (Zeng et al. 2018)
Was Ukraine_Eneolithic I6561 a Proto-Indo-European?