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Monday, October 16, 2017

Best of Davidski on South Asian population history

Very soon, perhaps even this year, we'll be seeing a major new paper from Harvard on the population history of South Asia. Apparently it'll be mostly based on ancient DNA from Bronze and Iron Age sites in present-day India and Pakistan. And yes, I know for a fact that it'll include Harappan samples from India.

It has to be said, unfortunately, that nearly all academic efforts to date to crack the mystery of the peopling of South Asia using DNA have been way below par, and often quite farcical. That's because ancient DNA relevant to South Asian population history hasn't been available for very long, and learning about ancient migrations and admixture events exclusively from modern-day DNA is really hard.

Also, I feel that many of these efforts have been ruined by politics. I don't want to harp on about that too much here, but it seems to me that the rather far fetched Out-of-India theory (OIT) has gained traction among many population geneticists of late simply because it's politically more palatable in the west than its main rival, the Aryan Invasion Theory (AIT). And that's mostly because the Nazis had a thing for Aryans, but also because AIT is seen by many Indians as an outdated concept used by the British during colonial times to legitimize their conquest of India.

Indeed, it's been a frustrating experience for me, and many others I'm sure, watching this nonsense unfold for the past 10-15 years. But on a positive note, it's forced me to look at this issue in more detail and produce a lot of solid work. It might be a good time now to recap this work. Below, sorted more or less in terms of awesomeness, is the best of Davidski on South Asia:

Ancient herders from the Pontic-Caspian steppe crashed into India: no ifs or buts

The Out-of-India Theory (OIT) challenge: can we hear a viable argument for once?

The peopling of South Asia: an illustrated guide

Children of the Divine Twins

The pseudo-steppe theory: last line of defense against the inevitable

A moment of clarity

Indian genetic history in three simple graphs

Caste is in the genes

The Poltavka outlier

Through time AND space?

The Indo-Europeanization of South Asia: migration or invasion?

These blog posts have already been read by many thousands of people, and, somewhat surprisingly for me, even made a decent splash on social media such as Facebook, Twitter and Reddit. The screen cap below is from a thread at a Desi Reddit community called ABCDesis (see here).

Most of these Desis are highly skeptical of my arguments, which isn't unusual, nor is it surprising, considering the massive amount of anti-AIT/pro-OIT nonsense that has been dumped online in recent years. But I promise, most of my stuff on South Asia will still be relevant after the new Harvard paper touches down.


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Rob said...

@ Al
Yes it's hard to say other than between 4000 & 2000 BC seems justified .
I'm inclined to go with Coleman's "coming" of c 3500 BC. Of course there was no conplete rupture within the PiE, and the chariots and Greek-IA convergences attest to contacts with MBA steppe.

Davidski said...

Three out of the four Mycenaean samples are from the Peloponnese, so Peloponnese_Neolithic has to be it.

But I agree that only one or two of the Peloponnese_Neolithic are valid, with the others being too old.

I3920 is dated to 3933-3706 calBCE (5000±25 BP) and is also the highest coverage Peloponnese_Neolithic with the most markers. So she is it.

And now we wait.

Samurai Jack said...

Another deluded moron shameful of his grunting barbaric European ancestors and trying to hijack Ancient Indian legacy. Just wait and watch as your bullshit is exposed in the new research paper.

Rob said...

@ Dave
Not necessarily, because I3920 is a relict. That type of EEF got replaced/ heavily admixed by another
It's probably similar to where most British BB got their neolithic ancestry form - Germany rather than direct local predecessors

Davidski said...

Yeah, a relict of pre-Mycenaean Peloponnese.

And the stats will show us if it's relevant to Mycenaean ancestry.

Rob said...

Ah Dave, i remember Matt made point that the new PCA in Mathieson, the Peloponesian Neolithics now look more like regular ANF, but with a couple shifted toward Anatolia BA, rather than southward ('ultra-basal') toward Levant. Looking at it, he's correct.
So it;ll be interesting to see what they look like, and of course, some upcoming 4000 - 2000 B 'interval' period Mainland data, if/ when that comes

Matt said...

One of the things I would comment about Lazaridis's analysis from the paper is, having looked at it, in terms of how they chose their working models with qpAdm, it seems like the methodology is that they tested for populations that would form a valid Rank=x qpWave* with Mycenaeans / Minoans, and then they ran qpAdm based on those.

So, when they haven't used models including the Peloponnese_Neolithic, this may be because these did not produce valid qpWave (e.g. sufficient P value) for them? This is actually not totally clear to me though...

It seems like a qpWave led process though, either way, rather than based on select what seems most valid or testing qpAdm fits first.

*using their 16 pop All set, then their 27 pop All+ set.

Davidski said...

It's pretty clear what happened in southern Greece during the Bronze Age and Peloponnese_Neolithic will be very important in demonstrating it, because the earliest Peloponnese_Neolithic sample clusters with Anatolia_N while the youngest and highest coverage, which is I3920, with the Minoans.

Of course, I can run qpWave as well as qpAdm analyses to make sure everything's legit, and I'm sure others can double check my work; this is not a problem.

Matt said...

@Davidski, I guess if you formally wanted to show that, Lazaridis tested whether the Mycenaeans formed a clade in qpWave by: "More formally, we tested all (4 2) = 6 pairs of Mycenaean individuals in our dataset as a Left list, using the All as the Right list. All 6 pairs were consistent with forming a clade with respect to the All set to the limits of our resolution (p-value for rank=0 ≥0.08)."

You could show that the Peloponnese Neolithic do not form a clade (e.g. some are offset in relatedness to CHG?) using the same methodology.

Davidski said...

Sure, I can run that test on the Peloponnese_Neolithic set.

Rob said...

It depends on where the 2200 BC eastern migration arrived from. If its south Anatolian Minoan, then it might bring the scenario something like:

"Tepecik_Ciftlik_N" 43.15
"Greece_LN" 25.35
"Srubnaya" 14.3

But I'm not sure. In such model, Minoans are pred. LN Greece, but then Iran Chalc. & also some minor Srubna.

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