In 2015 Massive migration from the steppe was a source for Indo-European languages in Europe and Population genomics of Bronze Age Eurasia were published. These two papers were game-changers. They established that the Yamnaya pastoralists of the Pontic steppe contributed a substantial proportion of ancestry to modern Europeans (later, the same was found to be the case in Indians and other Asians). As I’ve been reading and thinking about the expansion of Indo-Europeans ~3000 BC for my Substack series on the steppe, I have come to the conclusion that the populations sampled in these two papers were actually marginal to the primary expansion.
The first thing to note is that the Yamnaya samples were R1b, but of a haplogroup distinctive from that of the R1b common in Western Europe, and brought by the Bell Beakers. The Yamnaya R1b is the same as that in the Afanesievo culture of western Mongolia though. The early Corded Ware tended to be R1a. How to resolve this issue? On my podcast about Indo-Europeans with David Anthony, he posits that the elite during the early period was R1b, but that later on R1a (and Bell Beaker R1b) came to the fore due to social convulsions. Perhaps.
I think the other option, that there’s unsampled paternal diversity, is more plausible. I labeled where the 2015 Yamnaya were sampled from. It seems like they’re on the eastern end of the Yamnaya range. Anthony in The Horse, The Wheel, and Language, seems to lean toward the position that these eastern Yamnaya were culturally more significant than the less nomadic western Yamnaya. That’s fine, but I think it was the western Yamnaya that were the precursors to the Bell Beaker and Corded Ware. In my conversation with Nick Patterson he mentions that the Reich lab has detected Corded Ware who descend from the Yamnaya samples genealogically. How to square this with what I’m saying above?
The people of the Yamnaya horizon were patrilineal and exogamous. If Corded Ware men took Neolithic wives, they almost certainly took Yamnaya wives. The western and eastern Yamnaya may have had different paternal lineages, and even been different ethnolinguistically, but still shared similar gods and folkways so that intermarriage occurred. Their autosomal genome was very similar because exchanging wives across these patrilineal kindreds was common and prevent whole-genome distinctiveness from building up.
It needs to be noted that it turns out direct descendants of the Yamnaya R1b variant are present in Eastern Europe and the steppe to this day. A Russian group has found Yamnaya R1b in Crimean Tatars, and this lineage is also found in Chuvash. Basically, the eastern Yamnaya ancestry has been sloshing around the steppe for thousands of years. After 2000 BC they were absorbed into Indo-Iranians, but their far eastern outliers, the Afanesievo maintained some cultural continuity in the form of the Tocharian languages.
Finally, an issue in regards to time depth. The R1a division between Asian and European variants seems to date to 3500 BC. The paper above suggests that the division between Yamnaya R1b and Bell Beaker R1b dates to 4000 BC. The Yamnaya horizon people underwent a cultural revolution in the century or so prior to 3000 BC. But, they have differentiated already. On Clubhouse, I was talking to Jack V. of the Ancient Greece Decoded podcast, and he has a hard time believing that Indo-European diversified around 3000 BC. He says he can already read and understand Mycenanaen Greek from 1500 BC.
I put “Yamnaya”, “Corded Ware” and “Bell Beakers” in quotes. This isn’t what they called themselves. We’ll never know their ethnolinguistic divisions. They were probably part of a broad array of related peoples, more united by lifestyle and religion than language.
Note: the main issue I wonder about is the new samples that the Reich lab has and what they know.