There is a myth, created by professional geneticists, that the Proto-Indo-Europeans (PIE) were genetically 50% Eastern European Hunter-Gatherer (EHG) and 50% Caucasus Hunter-Gatherer (CHG). No doubt they run with this narrative because they are predominantly Leftists who are obsessed with overinflating the “non-European” origin of modern Europeans. David Reich has implied that this is his intention on numerous occasions.
I wouldn’t really mind if 50% of our PIE ancestry came from CHG. Yeah, okay, half of our PIE ancestry came from people who basically looked like modern Georgians. Totally owned the “racist nazis” with that one.
But this claim is simply not true. The PIE population arose predominantly from EHG men intermarrying with CHG women, which is obvious from the fact that PIE men carry EHG Y-DNA haplogroups (male lineages). Levels of CHG ancestry varied throughout the PIE population depending on the time and location of the PIE ethnic/cultural group in question. For example, Sredny Stog from Ukraine had very low levels of CHG ancestry, but PIE from the Progress and Vonyuchka cemeteries (located immediately next to the Caucasus mountains themselves) did have around 50/50 EHG:CHG ancestry.
The early Corded Ware population, which was responsible for the overwhelming majority of PIE expansion throughout Eurasia, had ~60% EHG, ~25-30% CHG, and ~10-15 ANF (Anatolian Neolithic Farmer) ancestry. Modern Northern Europeans descend ~50% from this population, and they have ~15% CHG ancestry on average. So, this is obviously accurate.
Yamnaya had ~55:35% EHG:CHG, with ~5-10% ANF. However, Yamnaya migrations appear to have been limited to the Greco-Balkans region (via Catacomb Culture) and Altai-Mongolia (via Afanasievo Culture). The origin of the Anatolians and Phrygians is currently unconfirmed, but Yamnaya may have been involved with the latter.
Below is an admixture analysis of PIE populations including all of the sample locations that I’m aware of. Non-PIE EHGs are labeled as such. WHG is West European Hunter-Gatherer and IRN is Iranian Neolithic Farmer, a population similar to CHG.
So, as you can see, some PIE groups had 50:50 EHG:CHG. However, in terms of PIE cultures that had an impact outside of the steppe and forest-steppe zone, their ancestry levels averaged at just under 60% EHG, just over 30% CHG, and around 10% Anatolian Farmer. That’s almost one grandparent of a genetic difference from the acclaimed 50:50 figure.