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Wednesday, September 11, 2019

Y-haplogroup R1a and mental health


I've updated my map of pre-Corded Ware culture R1a samples with a couple of new entries from Central and South Asia (the original is still here). However, before any of you get overly excited, please note that these samples aren't older than the Corded Ware culture. The reason I added them to my map is to counter the ongoing absurd claims online that South Asian R1a isn't derived from European R1a.


Just in case the map can't be viewed in all of its glory in some devices, here's what the fine print says:

The oldest example of R1a in ancient DNA from Central Asia is dated to 2132-1940 calBCE (ID I3770, Narasimhan 2019). Moreover, this sequence is closely related to much older R1a samples from Central, Eastern and Northern Europe, and phylogenetically nested within their diversity. Thus, it must surely represent a population expansion from Europe to Central Asia. Indeed, it's also associated with the Bronze Age Andronovo archeological culture, which is usually seen as an offshoot of the Corded Ware culture (CWC) of Late Neolithic Europe. The vast majority of present-day R1a lineages in Central Asia are closely related to that of I3770, and so must also ultimately derive from Europe.

The oldest instance of R1a in ancient DNA from South Asia is dated to just 1044-922 calBCE (ID I12457, Narasimhan 2019). This sequence, as well as the vast majority of present-day South Asian R1a lineages, are closely related to much older R1a samples from Central, Eastern and Northern Europe, and phylogenetically nested within their diversity. Thus, they must surely represent a population expansion from Europe to South Asia via Central Asia, in all likelihood during the Bronze Age. Even if R1a existed in South Asia before the Bronze Age, which is extremely unlikely, because it's found in samples from indigenous European hunter-gatherers, the vast majority of present-day R1a lineages in South Asia must be ultimately from Europe.

The idea that most, if not all, South Asian R1a is derived from European R1a seriously scares a lot of people. This is obvious in many online discussions on the topic. I suspect they're so frightened by it because, in their minds, it has the potential to encourage discrimination and even racism, perhaps by re-defining the colonization of much of the world by European nations in the recent past as the natural order of things?

In any case, clearly we're dealing with some sort of mass phobia here. I've got advice for those of you suffering from this problem: if you're honestly worried that the geographic provenance and expansion history of some Y-haplogroup is going to negatively impact on your life in any meaningful way, then it's time to find yourself a quality mental health professional. All the best with that.

See also...

The mystery of the Sintashta people

The Poltavka outlier

Yamnaya isn't from Iran just like R1a isn't from India

Thursday, September 5, 2019

On the surprising genetic origins of the Harappan people (Shinde et al. 2019)


The long awaited paper with ancient DNA from the Indus Valley Civilization (IVC) site of Rakhigarhi has finally arrived. Courtesy of Shinde et al. at Current Biology:

An ancient Harappan genome lacks ancestry from Steppe pastoralists or Iranian farmers

The bad news is that the paper features just one low coverage IVC genome, and it belongs to a female, so there's no Y-haplogroup. However, importantly, this individual is very similar to genetic outliers from Bronze Age West and Central Asia known as Indus_Periphery. So much so, in fact, that they could easily be from the same gene pool.

This, of course, gives strong support to the idea that Indus_Periphery is a useful stand-in for the real IVC population (see here).

Surprisingly, despite being largely of West Eurasian origin, the IVC people possibly didn't harbor any ancestry from the Neolithic farmers of the Fertile Crescent or even the Iranian Plateau.

That's because, according to Shinde et al., their West Eurasian ancestors separated genetically from those of the early Holocene populations of what is now western and northern Iran around 12,000 BCE. In other words, well before the advent of agriculture.


This surely complicates matters for those arguing that Indo-European languages may have arrived in the Indian subcontinent with early farmers via the Iranian Plateau. The more widely accepted theory is that Indo-European languages spread into South Asia with Bronze Age pastoralists from the Eurasian steppes. See here...


Update 05/09/2019: I had a quick look at the ancient Rakhigarhi individual with qpAdm, just to confirm for myself that she was indeed largely of West Eurasian origin and practically indistinguishable from Indus_Periphery. The genotype data that I used are freely available here.

IND_Rakhigarhi_BA
IRN_Ganj_Dareh_N 0.711±0.065
Onge 0.232±0.067
RUS_Tyumen_HG 0.057±0.059
chisq 13.251
tail prob 0.0392147
Full output

Indus_Periphery
IRN_Ganj_Dareh_N 0.674±0.015
Onge 0.237±0.014
RUS_Tyumen_HG 0.090±0.012
chisq 14.877
tail prob 0.0212326
Full output

Indus_Periphery
IND_Rakhigarhi_BA 0.946±0.074
Onge 0.054±0.074
chisq 10.358
tail prob 0.169152
Full output

This does appear to be the case, although it's also obvious that my models are missing something important because their statistical fits are rather poor. I'm guessing the main problem is trying to use the Onge people of the Andaman Islands as a proxy for the indigenous foragers of the Indian subcontinent.

See also...

Y-haplogroup R1a and mental health

Monday, September 2, 2019

Commoner or elite?


I recently started looking at the correlations between Y-chromosome haplogroups and social standing in ancient Europe, and was surprised by what I learned about the five currently sampled prehistoric Scandinavians belonging to Y-haplogroup R1b. I certainly wasn't expecting to uncover these stories about a mass human sacrifice, a bog body, and an Arctic circle warrior:

- The earliest Scandinavian in the ancient DNA record belonging to R1b comes from a grave site in what is now northern Norway (VK531, Margaryan et al. 2019). This individual has a genome-wide profile similar to that of local Mesolithic hunter-gatherers, but is dated to just ~2,400 BCE. During this time, Scandinavia was dominated by a "new" population associated with the Battle-Axe culture (BAC), with high levels of ancestry from the steppes of Eastern Europe. Since VK531 wasn't buried with any BAC grave goods, and indeed with no grave goods at all, it's possible that he may have been from a remnant forager population that was displaced and ultimately forced into extinction.

- R1b-U106 is today by far the most common R1b subclade in Scandinavia, but it's not yet clear how it managed to attain this status. Was it perhaps through elite dominance? The earliest ancient individual belonging to R1b-U106 is dated to 2275-2032 calBCE and comes from a Late Neolithic, likely post-BAC burial ground in what is now Sweden (RISE98, Lilla Beddinge, grave 49, southern skeleton, Allentoft et al. 2015). However, RISE98 wasn't buried in any way that would suggest he was an individual of high social standing. In fact, he was found in a mass grave, along with two other adults and two infants, possibly representing a human sacrifice. The only artefact in the grave was a bone needle. More details are available here.

- During the Nordic Bronze Age it became customary for Scandinavian elites to be laid to rest in richly furnished barrows, while commoners were buried in flat graves with few or no offerings. Human remains recovered from a "commoner" flat grave cemetery dated to the Early Bronze Age near the present-day city of Aalborg, northern Denmark, included the skeleton of a male belonging to Y-haplogroup R1b-M269 (RISE47, grave 3, skeleton 8, Allentoft et al. 2015). Keep in mind, however, that this might have been another case of an ancient Scandinavian R1b-U106 if not for missing data. A flint dagger was found alongside one of the skeletons in this cemetery, but RISE47 wasn't accompanied by any grave goods (see here).

- One of the most amazing archeological discoveries made in Scandinavia is the Trundholm Sun Chariot. Found in a peat bog on the island of Zealand, Denmark, in 1902, it's thought to be an Indo-European religious artefact dating back to the Nordic Bronze Age; a representation of a horse pulling the sun and perhaps also the moon in a spoked wheel chariot. Another important discovery in a peat bog near Trundholm dating to the Nordic Bronze Age was the body of a man belonging to R1b-M269 (RISE276, Trundholm mose II, bog find 1940, Allentoft et al. 2015). However, chances are slim that RISE276 was a charioteer or, say, a spiritual guru who accidentally drowned in the bog. Most Danish bog bodies are thought to have belonged to sacrificial victims or executed criminals.

- Interestingly, the earliest likely Scandinavian warrior belonging to R1b, and also R1b-U106, is from an early Iron Age burial in present-day northwestern Norway (VK418, Margaryan et al. 2019). This site isn't quite as far north as the grave of the above mentioned VK531, but it's still well within the Arctic circle. Apparently, VK418 was buried with some impressive weapons, potentially of "eastern origin", including a shield, spearheads and a sword. Who knows, he may even have been an elite warrior for his time and place?

The other two main Scandinavian Y-haplogroups, I1a and R1a, haven't yet been found in prehistoric Nordic remains from such, shall we say, depressing burials. That's not to say, of course, that they won't be sooner or later. RISE175, from Allentoft et al. 2015, is currently the only individual who fits the bill as a representative of the Nordic Bronze Age elite. He was buried in a barrow grave in what is now southwest Sweden and probably belongs to Y-haplogroup I1a. That's not much to go on, but perhaps it's a sign of things to come?


See also...

Isotopes vs ancient DNA in prehistoric Scandinavia

Who were the people of the Nordic Bronze Age?

They came, they saw, and they mixed