Confirmation bias

Every time I put up a thread that is even remotely linked to the Proto-Indo-European (PIE) homeland debate it gets hijacked by people who appear to have a pathological hate for the Kurgan PIE theory.

You'd think that considering the latest ancient DNA results from across Eurasia, which have thus far been very favorable to the Kurgan theory, these people would pipe down a little, at least for the time being, until something shows up that genuinely supports their stance. But nope.

The amount of confirmation bias in such threads is phenomenal. I'm going to start blocking and deleting the worst examples of this nonsense from now on. I'd also urge all reasonable and objective commentators here to try and ignore such comments, so that the offenders are left with no one to talk to.

If you're not quite sure how to spot an off-the-dial confirmation bias effort, here's an example from the last thread. I couldn't be bothered replying to this claptrap initially, but I will now, just to illustrate how off the mark it really is.

The truth is coming out.

Wonderful. Let's hear it.

EBA in South Asians is closer to Afanasievo than to Andronovo.

Maybe, but Afanasievo and Andronovo genomes aren't all that different, and at the moment we only have four Andronovo individuals, presumably from elite burials.

Who knows what more sampling from the territory of the vast Andronovo horizon, and a wider cross section of the Andronovo population, is going to uncover? We might find Andronovo samples that are perfect proxies for the Early Bronze Age (EBA) steppe admixture in South Asians; better than Afanasievo even.

Andronovo is different from Afanasievo because of Western/Caucasus expansions.

No, actually, Andronovo has Middle Neolithic farmer admixture from deep in Europe that Afanasievo lacks, or at least has much less of. Considering the preponderance of Y-haplogroup R1a in Andronovo remains, this admixture was probably mediated via female gene flow at the western edge of the Western Steppe, not near the Caucasus.

Afanasievo is leaning exclusively (for now) R1b. South Asians do not have Andronovo DNA.

As per above, South Asians may well have Andronovo ancestry. Or they may have ancestry from an R1a-rich sister group to the early Corded Ware population, which, based on an early Baltic Corded Ware genome, was in all likelihood basically identical to Afanasievo and Yamnaya in terms of genome-wide genetic structure (see here).

Ergo, EBA in South Asians did not come from Afanasievo. And R1a did not arrive in South Asia with Yamnayans or Andronovo/Afan.

But like I say, R1a may have arrived in South Asia with a Corded Ware-related population basically identical to Afanasievo and Yamnaya. Or with an Andronovo group basically identical to Afanasievo and Yamnaya.

This leads to at least three options:

1) PIE did not come from R1a or R1b, but J2. @Nirjhar J2 is present is UC Indians.

Y-haplogroups don't speak languages, so there's that. But we might be able to say, with a high degree of confidence, which Y-haplogroups were common in the PIE community based on their frequencies in ancient and modern-day populations.

Clearly, as things stand, the best candidates for so called PIE markers are R1a and R1b, and probably more specifically R1a-M417 and R1b-M269. J2 is a poor candidate for an PIE marker. See here: Y-hg J2 cannot be a Proto-Indo-European marker

2) R1a is source of PIE and did not come from Yamnaya, Andronovo, Afanasievo.

Well, most of the R1a in the world today may well be from an as yet unsampled Yamnaya population from the Pontic Steppe north of the Black Sea.

3) PIE came from several haplogroups, likely Caucasus area.

But why, considering the predominance of R1a and R1b on the ancient steppe and in modern-day speakers of Indo-European languages?

There are two potential locations for R1a. And I'm fine with both because they've made sense from the very beginning, unlike Yamnaya.

You mean the two potential main expansion points for most of the R1a in the world today? Surely either the Pontic Steppe or the Caspian Steppe?

One thing certain, R1a does not come from anywhere near Europe.

Hard to say where R1a comes from originally. My bet is that it was born in Upper Paleolithic Siberia, on the Mammoth Steppe that straddled Europe and Asia, possibly at a location very close to Europe.

R1a was the invasion that pushed R1b to the oceans of the Atlantic.

Actually, it seems that R1a-rich and R1b-rich steppe clans did their own thing when expanding into Asia and Europe during the Eneolithic and Early Bronze Age, and there's no evidence that they got in each other's way.

It's only during the Middle and Late Bronze Age that we see a population shift from R1b-rich to R1a-rich groups on the Caspian Steppe. This shift may have been accompanied by violence and language change, but if so, it's likely that one Indo-European language replaced another.

Also, please note that this R1a-rich population came from somewhere west of the Caspian Steppe, possibly the Pontic Steppe or the nearby forest steppe, because it had a higher level of Middle Neolithic European farmer admixture than the R1b-rich population that it replaced. So it's impossible to posit that this was an invasion from Asia, that pushed the R1b-rich population to the Atlantic.

This reply didn't take me long to put together. All I did was knock down the proverbial straw man over and over again. Easy work. But, at the same time, irritating and depressing.

Main take away point: if someone claims to know the "truth", chances are they're full of shit.