Last word on PIE genetics (for now)

Of course, by the time I start to figure something out, it's often old news to the real specialists in their field.  But, I can take some comfort in thinking that I largely started figuring this out a bit on my own after reading Carlos Quiles pioneering work and Davidski's take-down of his hypothesis.  That's something, right?

https://www.eupedia.com/forum/threads/34614-Oldest-R1a-M417-yet-guess-where-it-was-found

This brief discussion has a few highlights:

• R1a-M417 found in a Sredi Stog II individual, originally excavated by Dmitri Telegin in the 70s.
• Reiterates again the big difference between eastern and western steppe y-DNA, with regards to the R1a and R1b lineages that later appear in the Corded Ware and Yamnaya cultures respectively.  It is unlikely that PIE originated over the entire steppe area, or even that the entire steppe area was really all that homogeneous ethnically (and therefore, presumably linguistically) anyway.
• Proposes that actually the R1a guys are the more likely PIE originators rather than the R1b from the east that come from Khvalyinsk => Repin => Yamnaya, since the east lacked the cultural elements necessary to form the farming vocabulary of PIE
• Before everyone got all crazy with genetics, Sredni Stog was already proposed on an archaeological basis as the likely origin of Corded Ware.  After flirting faddishly with Yamnaya, it now looks like we might be back to the archaeological solution after all.
• More Sredni Stog and especially Maykop samples are needed.
• In general, sample size (and therefore assumptions of sample representativeness) are a bit of a problem with some of the sweeping generalizations and conclusions drawn from genetic evidence so far, and conclusions could get turned on their ear with just a few more samples.

Anyway, the formation of Indo-European, even within the steppe milieu, is actually and obviously much more complicated that it's sometimes been proposed.  Marija Gimbutas, J. P. Mallory and Dave Anthony have all advanced the state of knowledge of the question, but all had to work without some of the data that is available now.  On the other hand, people today are often a little too anxious to run off with some sexy new piece of data and the tail ends up wagging the dog.  This is still a collaborative and multidisciplinarian question; archaeology, linguistics and archaeogenetics all have their place in telling the story of the origin and spread of the Indo-European languages and cultural package, and the story without one of those disciplines is probably wrong, or at least incomplete.

There's still a lot of questions to be answered about the relationship between the R1a and R1b lineages on the steppe, because they still cluster and don't mingle very much (although, again—more samples could change this apparent picture.)  This is especially true for periods of proposed Indo-European unity.  Heck, even now, there's a pretty decent split between Western and Eastern Europe, although it should be noted that populations of both are Indo-European speakers.  So, what model gives them both Indo-European languages without there being much mingling between the two y-DNA lineages, anyway?  Don't know.  R1a does seem to be associated more with the satem languages, but of course, the split between R1a and R1b is way too old to be linguistically useful in that sense.  But there were at least two populations of Indo-European language speakers, with different paternal lineages in the early days of Indo-European post-unity, and there is a correlation with satem and centum languages between these two lineages.  Maybe one group is a substrate or adstrate and picked up the language without much in the way of demic diffusion.  But that was the basis for Quiles' Uralic substrate hypothesis, which probably doesn't work, because there are better candidates for the source of Uralic languages from both a linguistic and archaeological and genetic standpoint.  But, he may well have been right about one thing; there were two distinct "globs" of steppe populations, and they still remained viscous and clumpy rather than mingling together to come out the other end as a clear hybrid.  A dominant superstrate of one portion of the population over the other is the go-to solution (and even before genetics entered the picture, late Khvalynsk culturally dominant elements over Sredni Stog II and Dereivka was already being proposed.)  But we don't have enough genetic samples to test this hypothesis yet, and even if we did, it's often hard to try and suss out the relative cultural importance of the individual who was buried who we're taking DNA from.

Any solution that handwaves the distinction between these two paternal lineages as insignificant or unimportant is not convincing. The Yamnaya and Corded Ware had significantly different DNA. More work needs to be done to explain the mystery still implicit in what we know so far.

Based just on those maps, I'd almost suggest that the R1b element might be associated with CHG expansions into the steppe.  Maybe.  I think that's still an open question about the origin of the PIE and pre-PIE population of the steppes; what relationship did the CHG (Maykop, presumably) peoples have with the Dnieper-Donets and Samara and early steppe populations as they eventually evolved into more recognizably Indo-European cultural packages with Sredni Stog, Khvalynsk, Dereivka, and finally Yamnaya, anyway?  Foreign elite dominant superstrate, maybe?