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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

Tuesday, August 27, 2019

Isotopes vs ancient DNA in prehistoric Scandinavia


Four of the samples from the recent Frei et al. paper on human mobility in prehistoric southern Scandinavia are in my Global25 datasheets. Their genomes were published along with Allentoft et al. back in 2015. So I thought it might be interesting to check whether their strontium isotope ratios correlated with their genomic profiles.

In the Principal Component Analysis (PCA) below, RISE61 is a subtle outlier along the horizontal axis compared to the other three Nordic ancients, as well as a Danish individual representative of the present-day Danish gene pool. Also note that RISE61 shows the most unusual strontium isotope ratio (0.712588). The PCA was run with an online tool freely available here.


To help drive the point home, here's a figure from Frei et al., edited by me to show the positions of RISE47, RISE61 and RISE71. If RISE276 was also in this graph, he'd be sitting well under the "local" baseline, in roughly the same spot along the vertical axis as RISE47.


Interestingly, RISE61 belongs to Y-chromosome haplogroup R1a-M417, while RISE47 and RISE276, who appear to have been locals, both belong to R1b-M269. My guess is that RISE61 was a recent migrant from a more northerly part of Scandinavia dominated by the Battle-Axe culture (BAC). The BAC population was probably rich in R1a-M417 because it moved into Scandinavia from the Pontic-Caspian steppe via the East Baltic. This is what Frei et al. say about RISE61 and his burial site:

The double passage grave of Kyndeløse (Fig 1, S1 File) located on the island of Zealand yielded 70 individuals as well as a large number of grave goods, including flint artefacts, ceramics, and tooth and amber beads. We conducted strontium isotope analyses of seven individuals from Kyndeløse encompassing a period of c. 1000 years, indicating the prolonged use of this passage grave. The oldest of the seven individuals is a female (RISE 65) from whom we measured a “local” strontium isotope signature ( 87 Sr/ 86 Sr = 0.7099). Similar values were measured in five other individuals, including adult males and females. Only a single individual from Kyndeløse, an adult male (RISE 61) yielded a somewhat different strontium isotope signature of 87 Sr/ 86 Sr = 0.7126 which seems to indicate a non-local provenance. The skull of this male individual revealed healed porosities in the eye orbits, cribra orbitalia, a condition which is possibly linked to a vitamin deficiency during childhood, such as iron deficiency.

By the way, RISE47 was buried in a flat grave, which suggests that he was a commoner. RISE276 was found in a peat bog in Trundholm, where the famous Trundholm sun chariot was discovered (see here). He may have been a human sacrifice.

Citation...

Frei KM, Bergerbrant S, Sjögren K-G, Jørkov ML, Lynnerup N, Harvig L, et al. (2019) Mapping human mobility during the third and second millennia BC in present-day Denmark. PLoS ONE 14(8): e0219850. https://doi.org/10.1371/journal.pone.0219850

See also...

Commoner or elite?

Who were the people of the Nordic Bronze Age?

They came, they saw, and they mixed

Tuesday, August 20, 2019

Roopkund Lake dead


Fifteen of the Roopkund Lake samples from the Harney et al. paper published today at Nature Communications made it into the Global25 datasheets. Look for the prefix IND_Roopkund here...

Global25 datasheet (scaled)

Global25 datasheet

Global25 pop averages (scaled)

Global25 pop averages

Their genotypes are freely available in a ~590K SNP dataset via the Reich Lab here. I might be able to run more of the samples at some point if and when they're released in a dataset with more SNPs.

In any case, much like everyone else, I don't have a clue how those Mediterranean migrants ended up in the Himalayas back in the 1800s, but I do know where they came from. Most appear to have been from Crete, while others from mainland Greece. However, one of the individuals that I was able to analyze with the Global25 was almost certainly an Anatolian Greek. Below are a couple of Principal Component Analyses (PCA) based on the Global25 data. The relevant datasheet is available here.


I don't yet have a strong opinion about the origins of the earlier, typically South Asian Roopkund dead. They may have been visitors from all over India, or members of different castes from northern India. A PCA with six of these individuals can be seen here and the relevant datasheet gotten here. Any thoughts? Feel free to share them in the comments below.

Update 23/08/2019: A new ~1240K SNP genotype dataset with the Roopkund Lake samples is now available here. More markers means that I can produce more accurate PCA and run almost twice as many of the samples. I've updated all of the datasheets accordingly. The links are the same.


See also...

Getting the most out of the Global25

A surprising twist to the Shirenzigou nomads story

The Poltavka outlier

Saturday, August 17, 2019

A surprising twist to the Shirenzigou nomads story


Remember those potentially Afanasievo-derived and Tocharian-related Shirenzigou nomads from the Ning et al. paper? Well, in my opinion, they're probably neither. The genotypes and other data for these Iron Age individuals from the eastern Tian Shan are available here.

Below are a few successful and not so successful qpAdm mixture models for them. Note that I tried to use a wide range of relevant "right pops", but also retain a lot of markers, specifically to be able to discriminate between different types of steppe and steppe-derived sources of gene flow (refer to the full output). Admittedly, the Shirenzigou nomads can be modeled with Afanasievo-related ancestry, but...

CHN_Shirenzigou_IA
KAZ_Botai 0.161±0.023
KAZ_Wusun 0.490±0.023
NPL_Mebrak_2125BP 0.349±0.019

chisq 5.793
tail prob 0.926172
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.143±0.022
NPL_Mebrak_2125BP 0.295±0.019
Saka_Tian_Shan 0.562±0.024

chisq 6.796
tail prob 0.870794
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.185±0.023
NPL_Mebrak_2125BP 0.428±0.021
RUS_Sintashta_MLBA 0.270±0.026
TJK_Sarazm_En 0.117±0.027

chisq 11.351
tail prob 0.414345
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.032±0.027
KAZ_Zevakinskiy_LBA 0.567±0.025
NPL_Mebrak_2125BP 0.401±0.019

chisq 15.157
tail prob 0.232961
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.452±0.031
RUS_Afanasievo 0.435±0.025
RUS_Okunevo_BA 0.114±0.049

chisq 19.808
tail prob 0.0708003
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.409±0.031
RUS_Okunevo_BA 0.173±0.050
Yamnaya_RUS_Caucasus 0.418±0.026

chisq 20.453
tail prob 0.0589872
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.464±0.033
RUS_Okunevo_BA 0.104±0.053
Yamnaya_RUS_Samara 0.432±0.027

chisq 27.189
tail prob 0.0072566
Full output

Both the Wusun and Saka are generally accepted to have been the speakers of Indo-Iranian languages. So it's possible that the Shirenzigou nomads were Indo-Iranian speakers too, or at least derived from such peoples.

Surprisingly, NPL_Mebrak_2125BP was the key to obtaining the best statistical fits. This is a trio of samples, roughly contemporaneous with the Shirenzigou nomads, from a burial site high up in the Himalayas in what is now Nepal (see here).

To be honest, I'm not quite sure why the Himalayan ancients work so well in my models. Perhaps they're just a really good proxy for an Iron Age population from the northern edge of the Tibetan Plateau?

By the way, most of the Shirenzigou nomads made it into the latest Global25 datasheets (see here). They can be analyzed in a variety of ways described in this blog post: Getting the most out of the Global25. Below is a screen cap of me comparing the effectiveness of Afanasievo, Sintashta and Wusun samples as proxies for the steppe ancestry in the Shirenzigou nomads with an online tool freely available here. As expected, the algorithm picks Sintashta ahead of Afanasievo, and the Wusun ahead of both.


See also...

They mixed up Huns with Tocharians

Some myths die hard

The mystery of the Sintashta people

Wednesday, August 14, 2019

Did South Caspian hunter-fishers really migrate to Eastern Europe?


The idea that most of the Near Eastern-related ancestry in the ancient populations of the Pontic-Caspian (PC) steppe is, one way or another, sourced from the territory of present-day Iran is a fairly popular one nowadays (for instance, see here). It might turn out to be correct, once there are enough relevant samples to test it properly, but in my opinion the chances of this are slim.

My skepticism is based on literally hours of analyses with the currently available ancients from the Caucaso-Caspian region, like, for instance, the admixture graphs below featuring foragers and early farmers from Russia, Georgia and Iran. The relevant qpGraph and dot files are available here.

Note that the further I move away from Eastern Europe in these graphs when looking for the source of the southern ancestry in the Eneolithic population from the southernmost part of the PC steppe (Piedmont_En), the more difficult it is for me to create a statistically sound model. What might this tell us about the provenance of this so called southern ancestry?




See also...

The PIE homeland controversy: August 2019 status report

Some myths die hard

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Friday, August 2, 2019

The PIE homeland controversy: August 2019 status report


Archeologist David Anthony has a new paper on the Indo-European homeland debate titled Archaeology, Genetics, and Language in the Steppes: A Comment on Bomhard. It's part of a series of articles dealing with Allan R. Bomhard's "Caucasian substrate hypothesis" in the latest edition of The Journal of Indo-European Studies. It's also available, without any restrictions, here.

Any thoughts? Feel free to share them in the comments below. Admittedly, I found this part somewhat puzzling (emphasis is mine):

It was the faint trace of WHG, perhaps 3% of whole Yamnaya genomes, that identified this admixture as coming from Europe, not the Caucasus, according to Wang et al. (2018). Colleagues in David Reich’s lab commented that this small fraction of WHG ancestry could have come from many different geographic places and populations.

I think that's highly optimistic. It really should be obvious by now thanks to archeological and ancient genomic data, including both uniparental and genome-wide variants, that the Yamnaya people were practically entirely derived from Eneolithic populations native to the Pontic-Caspian (PC) steppe. So, in all likelihood, this was also the source of their minor WHG ancestry.

Indeed, they clearly weren't some mishmash of geographically, culturally and genetically disparate groups that had just arrived in Eastern Europe, but the direct descendants of closely related and already significantly Yamnaya-like peoples associated with long-standing PC steppe archeological cultures such as Khvalynsk and Sredny Stog. I discussed this earlier this year, soon after the Wang et al. paper was published:

On Maykop ancestry in Yamnaya

I hope I'm wrong, but I get the feeling that the scientists at the Reich Lab are finding this difficult to accept, because it doesn't gel with their theory that archaic Proto-Indo-European (PIE) wasn't spoken on the PC steppe, but rather south of the Caucasus, and that late or rather nuclear PIE was introduced into the PC steppe by migrants from the Maykop culture who were somehow involved in the formation of the Yamnaya horizon.

Inexplicably, after citing Wang et al. on multiple occasions and arguing against any significant gene flow between Maykop and Yamnaya groups, Anthony fails to mention Steppe Maykop. But the Steppe Maykop people are an awesome argument against the idea that there was anything more than occasional mating between the Maykop and Yamnaya populations, because they were wedged between them, and yet clearly distinct from both, with a surprisingly high ratio of West Siberian forager-related ancestry (see here and here).


Despite all the talk lately about the potential cultural, linguistic and genetic ties between Maykop and Yamnaya, including claims that the latter possibly acquired its wagons from the former, my view is that the Steppe Maykop and Yamnaya wagon drivers may have competed with each other and eventually clashed in a big way. Indeed, take a look at what happens after Yamnaya burials rather suddenly replace those of Steppe Maykop just north of the Caucasus around 3,000 BCE.

Yamnaya_RUS_Caucasus
RUS_Progress_En_PG2001 0.808±0.058
RUS_Steppe_Maykop 0.000
UKR_Sredny_Stog_II_En_I6561 0.192±0.058
chisq 13.859
tail prob 0.383882
Full output

Yep, total population replacement with no significant gene flow between the two groups. Apparently, as far as I can tell, there's not even a hint that a few Steppe Maykop stragglers were incorporated into the ranks of the newcomers. Where did they go? Hard to say for now. Maybe they ran for the hills nearby?

Intriguingly, Anthony reveals a few details about new samples from three different Eneolithic steppe burial sites associated with the Khvalynsk culture:

The Reich lab now has whole-genome aDNA data from more than 30 individuals from three Eneolithic cemeteries in the Volga steppes between the cities of Saratov and Samara (Khlopkov Bugor, Khvalynsk, and Ekaterinovka), all dated around the middle of the fifth millennium BC.

...

Most of the males belonged to Y-chromosome haplogroup R1b1a, like almost all Yamnaya males, but Khvalynsk also had some minority Y-chromosome haplogroups (R1a, Q1a, J, I2a2) that do not appear or appear only rarely (I2a2) in Yamnaya graves.

As far as I can tell, he suggests that they'll be published in the forthcoming Narasimhan et al. paper. If so, it sounds like the paper will have many more ancient samples than its early preprint that was posted at bioRxiv last year.

For me the really fascinating thing in regards to these new samples is how scarce Y-haplogroup R1a appears to have been everywhere before the expansion by the putative Indo-European-speaking steppe ancestors of the Corded Ware culture (CWC) people. It's basically always outnumbered by other haplogroups wherever it's found prior to about 3,000 BCE, even on the PC steppe. But then, suddenly, its R1a-M417 subclade goes BOOM! And that's why I call it...

The beast among Y-haplogroups

At this stage, I'm not sure how to interpret the presence of Y-haplogroup J in the Khvalynsk population. It may or may not be important to the PIE homeland debate. Keep in mind that J is present in two foragers from Karelia and Popovo, northern Russia, dated to the Mesolithic period and with no obvious foreign ancestry. So it need not have arrived north of the Caspian as late as the Eneolithic with migrants rich in southern ancestry from the Caucasus or what is now Iran. In other words, for the time being, the steppe PIE homeland theory appears safe.

See also...

Did South Caspian hunter-fishers really migrate to Eastern Europe?

The PIE homeland controversy: January 2019 status report

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Sunday, July 28, 2019

They mixed up Huns with Tocharians


I don't yet have the genomes from the recent Ning et al. paper on the Iron Age nomads from the Shirenzigou site in the eastern Tian Shan. But I do have most of the previously published data featured in the paper, including the Damgaard et al. 2018 Hun and Saka samples from the western Tian Shan.

After reading the Ning et al. paper between the lines and running a few analyses of my own, it's clear to me that most of the supposedly Tocharian-related Shirenzigou individuals actually share a very close relationship with the Tian Shan Huns, and indeed may have been their ancestors.

For instance, Ning et al. found that a large part of the ancestry of the Shirenzigou ancients could be modeled with the Tian Shan Huns, which was an anachronistic approach because the former are older than the latter. They also found that Ulchi-related ancestry was a key part of the genetic structure of eight out of the ten Shirenzigou individuals, and this likewise appears to be an important part of the genetic structure of the Tian Shan Huns.

Note the strong statistical fits in the Global25/nMonte and qpAdm mixture models below, respectively, which characterize these Huns as a two-way mixture between the Ulchi and the earlier Tian Shan Saka. And keep in mind that the Saka also harbor significant Ulchi-related ancestry.

Hun_Tian_Shan
Saka_Tian_Shan,92
Ulchi,8

distance%=1.2553

Hun_Tian_Shan
Saka_Tian_Shan 0.928±0.009
Ulchi 0.072±0.009

chisq 4.409
tail prob 0.992464
Full output

Moreover, the Shirenzigou males belong to Y-haplogroups Q1a and R1b (two instances of each), and they share the latter with one of the Tian Shan Huns. Judging by the data from the relevant BAM files, it's also possible that the Shirenzigou males share a very rare subclade of R1b with the Hun, defined by the PH155 mutation (see here). The Y-haplogroup assignments for the other Tian Shan Huns end at R and R1, but that's almost certainly due to missing data.

On the other hand, two Tian Shan Sakas belong to Y-haplogroup R1a but none to R1b, which fits with the pattern from currently available ancient DNA that R1a was more common than R1b in Saka-related groups, such as the Scythians and Sarmatians (see here).

This is all very interesting, because the Huns replaced the Saka in the western Tian Shan, and, considering their R1b and excess Ulchi-related ancestry, very likely moved into the region from the direction of Shirenzigou. Indeed, in my opinion a strong argument can now be made that the Iron Age population from the Shirenzigou region took part in the formation of the Hunnic confederacy.

So where does that leave the theory presented by Ning et al. that the Shirenzigou ancients may have been closely related, and perhaps even ancestral, to the Tocharians, simply because they packed a lot of Yamnaya-related and possibly proto-Tocharian Afanasievo ancestry, and were living close to the Tarim Basin, where Tocharian languages were subsequently first attested?

I'm not sure, but I now find it difficult to reconcile this theory with the fact that they were closely related, and probably ancestral, to the Tian Shan Huns. As far as I'm aware, Huns cannot be linked to Tocharians in any meaningful way.

Of course it's possible that different Afanasievo-derived groups were living in the Tarim Basin and surrounds, and, as some merged with new populations pushing into the region from the east and adopted non-Indo-European languages, others retained their Tocharian speech and eventually split into communities speaking Tocharian A, B and apparently also C (see here).

But this has to be demonstrated directly with ancient DNA from archeological sites where Tocharian languages were attested. Till then, I'll keep thinking that Ning et al. wrote a paper about Tocharians that really should've been a paper about Huns.

Here's a famous wall painting of Tocharian princes from the cave of the sixteen sword-bearers in the Tarim Basin, dated to 432–538 AD. They don't look like guys with a lot of Ulchi-related admixture to me, but I might be wrong. Feel free to let me know what you think in the comments below.


Update 08/17/2019: The Shirenzigou nomads are now in my dataset. Below are a few successful and not so successful qpAdm mixture models for them. Note that I tried to use a wide range of relevant "right pops", but also retain a lot of markers, specifically to be able to discriminate between different types of steppe and steppe-derived sources of gene flow (refer to the full output). Admittedly, the Shirenzigou nomads can be modeled with Afanasievo-related ancestry, but...

CHN_Shirenzigou_IA
KAZ_Botai 0.161±0.023
KAZ_Wusun 0.490±0.023
NPL_Mebrak_2125BP 0.349±0.019

chisq 5.793
tail prob 0.926172
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.143±0.022
NPL_Mebrak_2125BP 0.295±0.019
Saka_Tian_Shan 0.562±0.024

chisq 6.796
tail prob 0.870794
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.185±0.023
NPL_Mebrak_2125BP 0.428±0.021
RUS_Sintashta_MLBA 0.270±0.026
TJK_Sarazm_En 0.117±0.027

chisq 11.351
tail prob 0.414345
Full output

CHN_Shirenzigou_IA
KAZ_Botai 0.032±0.027
KAZ_Zevakinskiy_LBA 0.567±0.025
NPL_Mebrak_2125BP 0.401±0.019

chisq 15.157
tail prob 0.232961
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.452±0.031
RUS_Afanasievo 0.435±0.025
RUS_Okunevo_BA 0.114±0.049

chisq 19.808
tail prob 0.0708003
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.409±0.031
RUS_Okunevo_BA 0.173±0.050
Yamnaya_RUS_Caucasus 0.418±0.026

chisq 20.453
tail prob 0.0589872
Full output

CHN_Shirenzigou_IA
NPL_Mebrak_2125BP 0.464±0.033
RUS_Okunevo_BA 0.104±0.053
Yamnaya_RUS_Samara 0.432±0.027

chisq 27.189
tail prob 0.0072566
Full output

Both the Wusun and Saka are generally accepted to have been the speakers of Indo-Iranian languages. So it's possible that the Shirenzigou nomads were Indo-Iranian speakers too, or at least derived from such peoples.

Surprisingly, NPL_Mebrak_2125BP was the key to obtaining the best statistical fits. This is a trio of samples, roughly contemporaneous with the Shirenzigou nomads, from a burial site high up in the Himalayas in what is now Nepal (see here).

To be honest, I'm not quite sure why the Himalayan ancients work so well in my models. Perhaps they're just a really good proxy for an Iron Age population from the northern part of the Tibetan Plateau? By the way, most of the Shirenzigou nomads made it into the latest Global25 datasheets (see here).

See also...

Almost everything you ever wanted to know about the Xiaohe-Gumugou cemeteries

The mystery of the Sintashta people

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Friday, July 26, 2019

Afanasievo people may well have been proto-Tocharian speakers (Ning et al. 2019)


Update 17/08/2019: A surprising twist to the Shirenzigou nomads story

...

During the Early Bronze Age, around 2,900 BCE, a population associated with the Yamnaya archeological culture migrated from the Pontic-Caspian steppe in Eastern Europe deep into Asia, as far as the Minusinsk Basin in South Siberia.

This rapid, long-range expansion was likely to have been the first significant migration of a Yamnaya-related group far to the east of the Ural Mountains, and it resulted in the formation of the Afanasievo archeological culture (see here).

The appearance of Tocharian languages in the Tarim Basin, in what is now western China, is often associated with the Afanasievo culture, mainly because of the confirmed presence of European-related populations in the Tarim Basin during the Bronze Age, as well as the likely highly divergent position of the Tocharian node in the Indo-European language phylogeny.

But the Afanasievo people were separated by considerable distance in space and time from the Tocharians, and can't yet be reliably linked to them with archeological or genetic data. So even though the inference that the former are linguistically ancestral to the latter is quite plausible, it's far from certain.

However, thanks to a new paper at Current Biology by Ning et al., at least we now know that a population with significant Yamnaya/Afanasievo-related ancestry was living in the eastern Tian Shan Mountains just a few hundred years before Tocharian languages were attested nearby [LINK]. Below is the paper summary, emphasis is mine:

Recent studies of early Bronze Age human genomes revealed a massive population expansion by individuals-related to the Yamnaya culture, from the Pontic Caspian steppe into Western and Eastern Eurasia, likely accompanied by the spread of Indo-European languages [1, 2, 3, 4, 5]. The south eastern extent of this migration is currently not known. Modern-day human populations from the Xinjiang region in northwestern China show a complex population history, with genetic links to both Eastern and Western Eurasia [6, 7, 8, 9, 10]. However, due to the lack of ancient genomic data, it remains unclear which source populations contributed to the Xinjiang population and what was the timing and the number of admixture events. Here, we report the first genome-wide data of 10 ancient individuals from northeastern Xinjiang. They are dated to around 2,200 years ago and were found at the Iron Age Shirenzigou site. We find them to be already genetically admixed between Eastern and Western Eurasians. We also find that the majority of the East Eurasian ancestry in the Shirenzigou individuals is-related to northeastern Asian populations, while the West Eurasian ancestry is best presented by ∼20% to 80% Yamnaya-like ancestry. Our data thus suggest a Western Eurasian steppe origin for at least part of the ancient Xinjiang population. Our findings furthermore support a Yamnaya-related origin for the now extinct Tocharian languages in the Tarim Basin, in southern Xinjiang.


Ning et al., Ancient Genomes Reveal Yamnaya-Related Ancestry and a Potential Source of Indo-European Speakers in Iron Age Tianshan, Current Biology, July 25, 2019, DOI: https://doi.org/10.1016/j.cub.2019.06.044

See also...

It was always going to be this way

The mystery of the Sintashta people

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...