Ghalichi et al. 2024 and the Indo-European question.
A new paper with more than 100 samples provided new details about the interaction of Eastern European populations and West Asians over Caucasus.
A new Mesolithic sample from north Caucasus (Satanae cave SJG001) dated at 6100BC yielded an interesting genetic profile. It was practically identic to other Eastern European hunter gatherers (EHG). The sample had the R1a haplogroup, from a minor branch (not the same as M417) that in
most likelihood is related to later IE migrations.
This EHG result from north Caucasus means that the genetic profile of Yamnaya didn't existed since the immemorial times but formed later than the 6000BC. Yamnaya has ancestry both from EHG and from south of Caucasus. The event that triggered the formation of Yamnaya better known as Steppe genetic profile was the apparition of farmers in South Caucasus. The Shulaveri-Aratashen-Shomutepe (SAS) culture starts no later than 6200BC. And starting from this period farmers mixed both with Caucasian hunter gatherers and made attempts to colonize the steppe in north of Caucasus.
A new case of J2b2a-L283 was found in steppe zone of North Caucasus (the ZO1002 on the map). It was dated at 3800BC, older than Maykop and Kura-Araxes. And already had some EHG admixture which means that it was probably a lineage descending from Shulaveri farmers trying to settle in steppe. Later this haplotype will become a rare Yamnaya lineage and will move to Balkans where it will have an important expansion.
Despite this finding the most predominant Y DNA in Eneolithic steppe pastoralistic groups had local Eastern European origin (R1 and I2) rather than from south of Caucasus. We have another Y DNA from Nalchik farmers and this time once more it's R1b. From the V1636 branch. We have also now one of oldest R1b-M269 from Konstantinovka dated at 3800BC. KST001.
So two important question arises..
Why despite having large amount of West Asian/Caucasian ancestry the Eneolithic steppe groups and Yamnaya has so little cases of J haplogroup.
And the second question is linguistic. Who's language was the Proto Indo Anatolian? Those from Shulaveri culture farmers or those from EHG / R1 side.
Before answering the first question we should note that this phenomenon of mismatch between autosomes occurred not only in East Europe but also in West Europe. After the initial success of G2 haplogroup , later there was a widespread resurgence of local I2 haplogroup. In British islands farmers for instance had 100% of I2 haplogroup. Yet in autosomes they had 70% of Anatolian farner ancestry.
There can be numerous theories to explain this. I am personally inclined to believe that social factors played a key role. Neolithic farmers of West Asia had more egalitarian or even matriarchal culture. A recent paper from Catalhoyuk showed an obvious matrilineal culture. While eastern European hunters could have more patriarchal culture. When a matriarchal and patriarchal cultures meet each other this affects in different ways the uniparental markers. Y DNA of one side will prevail and mtdna of the other side will also prevail.
There are other theories like mass killing of males. Those theories are popular in internet. But they can't explain one important thing. Why Scythians, Saka and Turkic tribes who are known to have a warrior culture and where frequently killing all males of the competing clan had one of most diverse Y DNA. The answer is self evident. Because during a conflict it's not granted that always one haplogroup prevails while others always are defeated. The outcome of the clans conflict can be very random which will create a very random distribution of haplogroups.
When farmers moved to north of Caucasus they were the technologically advanced side. It would be strange that they lost all battles without wining any of them and expanding their lineage. So wars and mass killings can't explain the emergence of this pattern. There can be other explanations. I just demonstrated one possible.
As for the linguistic part I will dedicate another topic