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Wednesday, April 7, 2021

The Bacho Kiro surprise (Hajdinjak et al. 2021)

Over at Nature at this LINK. The paper focuses on Neanderthal ancestry in Initial Upper Paleolithic (IUP) humans from what is now Bulgaria. But, to me, much more interesting is the claim by its authors that present-day East Asians harbor ancient European, or, at least, European-related ancestry. From the paper, emphasis is mine:

When we explored models of population history that are compatible with the observations above using admixture graphs [28], we found that the IUP Bacho Kiro Cave individuals were related to populations that contributed ancestry to the Tianyuan individual in China as well as, to a lesser extent, to the GoyetQ116-1 and Ust’Ishim individuals (all |Z| < 3; Fig. 2d, Supplementary Information 6). This resolves the previously unclear relationship between the GoyetQ116-1 and Tianyuan individuals [13] without the need for gene flow between these two geographically distant individuals.


In conclusion, the Bacho Kiro Cave genomes show that several distinct modern human populations existed during the early Upper Palaeolithic in Eurasia. Some of these populations, represented by the Oase1 and Ust’Ishim individuals, show no detectable affinities to later populations, whereas groups related to the IUP Bacho Kiro Cave individuals contributed to later populations with Asian ancestry as well as some western Eurasian humans such as the GoyetQ116-1 individual in Belgium. This is consistent with the fact that IUP archaeological assemblages are found from central and eastern Europe to present-day Mongolia [5,15,16] (Fig. 1), and a putative IUP dispersal that reached from eastern Europe to East Asia. Eventually populations related to the IUP Bacho Kiro Cave individuals disappeared in western Eurasia without leaving a detectable genetic contribution to later populations, as indicated by the fact that later individuals, including BK1653 at Bacho Kiro Cave, were closer to present-day European populations than to present-day Asian populations [29,30].

Hajdinjak, M., Mafessoni, F., Skov, L. et al. Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry. Nature 592, 253–257 (2021).

See also...

Ust'-Ishim belongs to K-M526

Wednesday, March 31, 2021

Against the conventional wisdom

I've read some very strange theories over the years trying to explain who was responsible for the so called Caucasus/Iranian-related ancestry in the Yamnaya people.

Proto-Indo-European speaking farmers from what is now Iran? How about Uruk invaders from Mesopotamia? No, wait, they were migrants from India who spoke Sanskrit. Haha.

Nope, it seems that hunter-gatherers rich in this type of ancestry lived north of the Caucasus already during the so called Pottery Neolithic or even the Mesolithic. That's the impression that I'm getting from watching the clip HERE.

This is basically also the idea that I gradually developed at this blog during the last few years, following common sense and logic, but totally against the conventional wisdom in regards to this topic. For instance, see here...

But here's my prediction: Steppe_EMBA only has 10-15% admixture from the post-Mesolithic Near East not including the North Caucasus, and basically all of this comes via female mediated gene flow from farming communities in the Caucasus and perhaps present-day Ukraine.
Modeling Steppe_EMBA

Of course, I could've done better with many of the details in my posts, like the dates and archeological links. But hey, at least I was smart enough to ignore the conventional wisdom.

I can't wait for the new ancient samples from the Pontic-Caspian steppe that David Anthony featured in his talks recently. Once I have them we'll be able to work out the details here for ourselves.

See also...

Ahead of the pack

Ancient DNA vs Ex Oriente Lux

Understanding the Eneolithic steppe

Monday, March 29, 2021

Khvalynsk is now out of the picture

The population associated with the Khvalynsk culture was not ancestral to the Yamnaya people. Archeologist David Anthony says so HERE. So where did the Yamnaya and Corded Ware populations come from? Anthony doesn't know yet.

See also...

Understanding the Eneolithic steppe

Ancient DNA vs Ex Oriente Lux

A final note for the year

Sunday, March 14, 2021

How the Shirenzigou nomads became Proto-Tocharians

A couple of years ago, the authors of a paper about a group of Iron Age nomads from the site of Shirenzigou, in the eastern Tian Shan, made a mistake. They wrongly assigned two of these nomads to Y-haplogroup R1b-M269.

This faux pas made them believe that the Shirenzigou nomads were closely related to the M269-rich population associated with the Afanasievo culture.

Indeed, since the Afanasievo culture was often credited with the spread of Tocharian languages to the Tarim Basin, these authors, led by Chao Ning, also concluded that the Shirenzigou nomads were potentially the missing link between the Afanasievo culture and the Tocharians (see here).

Moreover, Ning et al. used formal statistics to argue that the Shirenzegou nomads harbored Afanasievo-related genome-wide ancestry, rather than Sintashta-related genome-wide ancestry, despite the fact that the latter ancestry was widespread in the Tian Shan and surrounds during the Bronze and Iron ages. Soon after, another group of authors, led by Chuan-Chao Wang, also went out of their way to link the Shirenzigou nomads to the Afanasievo people with genome-wide DNA using formal statistics (see here).

Interestingly, one of the Shirenzigou nomads belongs to Y-haplogroup R1a-Z93, which is an obvious Sintashta-related lineage. Both Ning et al. and Wang et al. missed this important fact.

They also missed the key fact that the R1b lineage found in the Shirenzigou nomads actually belongs a native Central Asian subclade, which is only very distantly related to the originally Eastern European R1b-M269.

Now, formal stats are a very useful tool for studying genome-wide ancestry. But they're not infallible, and that's actually something of an understatement. Indeed, if you don't run sanity checks when using formal stats, you're likely to come to some unusual, even arse about face, conclusions. Uniparental markers, like Y-chromosome haplogroups, can provide a robust sanity check when running formal stats on genome-wide data.

One problem with formal stats is that Sintashta-related ancestry often looks very much like Afanasievo-related ancestry when it's mixed with indigenous Central Asian ancestry. Basically, the reason why this happens is that the Central Asian ancestry dampens the Early European Farmer (EEF) signal in the Sintashta-related ancestry.

This is an artifact that once caused scientists at Harvard to believe that Central Asian Scythians and present-day South Asians lacked Sintashta-related ancestry.

Unfortunately, since the publication of the Ning et al. paper, a consensus has emerged in academia that the Shirenzigou nomads are indeed the missing link between the Afanasievo culture and the Tocharians. But, let's be objective and honest here, it's a consensus based on nothing more than a comedy of errors.

On the other hand, me and most of the commentators at this blog have formed opinions about the Shirenzigou nomads that are totally at odds with the academic consensus, that:

- they're a complex mixture of Sintashta-related, indigenous Central Asian and Tibetan-related ancestries, with no clear, unambiguous signal of Afanasievo-related ancestry

- they weren't the speakers of Proto-Tocharian or even related in any specific way to the Tocharians

- they were probably the speakers of a now extinct Indo-Iranian language, and, at least based on geographic proximity, possibly related to the Yuezhi.

Feel free to make up your own mind. But for me, the question of how Tocharian languages ended up in the Tarim Basin remains wide open. I admit though, I'm currently quite partial to the idea floated here by commentator Copper Axe that the Chemurchek culture may have had something to do with it.

See also...

Don't believe everything you read in peer reviewed papers

Saturday, February 13, 2021

The Uralic cline with kra001 - no projection this time

A whole lot of nonsense was posted online, often by people who should've known better, after I claimed that kra001 was a solid proxy for a proto-Uralic genome (see here).

For those of you who still don't get it, below are three Principal Component Analysis (PCA) plots featuring Uralic speakers and other present-day Eurasians. Kra001 is also there. These graphs are based on genotype data not reprocessed Global25 data. The relevant datasheet is available here.

Compared to my previous PCA with kra001, here I included a bigger range of East Eurasian populations to help mitigate the effects of extreme genetic drift in some of the Siberian groups, at least on the first few Principal Components (PCs). Moreover, kra001 wasn't projected onto PCs computed with modern-day samples, so he was free to influence the outcome of the PCA.

Note the east to west clines made up largely of Uralic speaking groups on the first two plots. These plots are based on PCs 1/2 and 1 /3, respectively. The third plot, based on PCs 1/4, is more complex and thus more difficult to interpret, but it also manages to isolate many of the Uralic populations from the others.

The Uralic-specific clines do intersect with the clines and clusters formed by the other linguistic groups. However, based on the three plots, the Yeniseian-speaking Kets are the only Asian group that can plausibly be confused for Uralic speakers.

Importantly, apart from the Kets, kra001 is the only Asian individual who shifts his position on all three plots as if he were a Uralic speaker. This might well be a coincidence, and we'll never know what language was spoken by kra001, but it does suggest to me that his genome is a solid proxy for a proto-Uralic genome.

See also...

First taste of Early Medieval DNA from the Ural region

The BOO people: earliest Uralic speakers in the ancient DNA record?

Fresh off the sledge

Friday, February 5, 2021

Finally, a proto-Uralic genome

Obviously, genes don't speak languages, people do. But sometimes it's possible to associate a linguistic group with a very specific genetic signature.

A while ago many of us in the blogosphere spotted an uncanny connection between the Uralic language family, Y-haplogroup N-L1026 and Nganasan-like genome-wide genetic ancestry.

As a result, we expected a Nganasan-like population rich in N-L1026 to eventually appear in the ancient DNA record, probably somewhere in Siberia and in burials from a likely proto-Uralic archeological culture. This hasn't happened yet, but we now have direct evidence that such a population must have existed somewhere deep in Siberia as early as the Bronze Age.

Kra001, whose genome was published recently along with Kilinc et al., belongs to N-L1026 and, at least in terms of genome-wide genetic structure, could well be from a population directly ancestral to present-day Nganasans. Of course, the Nganasan language is part of the Samoyedic branch of Uralic.

Below is a series of Principal Component Analyses (PCA) featuring kra001. He's labeled RUS_Krasnoyarsk_BA, after the location and age of his burial. Note the obvious Uralic cline running across the plots. That is, from west to east. Kra001 is positioned at the end of this cline very close to a small cluster of Nganasans. To see interactive versions of the plots, paste the Global25 coordinates here into the relevant field here.

Admittedly, there's no way of knowing whether this individual spoke proto-Uralic or not. Indeed, he may have spoken something totally unrelated. The important point is that the very specific genetic signature shared by almost all present-day Uralic speakers, except perhaps Hungarians, is now finally represented in the ancient DNA record. And I can reveal to you that we'll soon be seeing many more ancients very similar to kra001 in upcoming papers.

See also...

The Uralic cline with kra001 - no projection this time

The BOO people: earliest Uralic speakers in the ancient DNA record?

Fresh off the sledge

Wednesday, January 27, 2021

The great shift

Here's a Principal Component Analysis (PCA) featuring some of the ancients from the recent Saag et al. paper at Science Advances. To see an interactive version of the plot paste the Global25 coordinates here into the relevant field here.

Note that the Fatyanovo culture agropastoralists, who are rich in Y-haplogroup R1a and steppe ancestry, cluster with present-day Eastern Europeans. On the other hand, the Volosovo culture singleton sits near the European hunter-gatherer cline that no longer exists.

This Volosovo individual belongs to Y-haplogroup Q1a. However, most of the Volosovo males whose genomes are soon to be published belong to Y-haplogroup R1b.

Thus, in much of Eastern Europe during the Bronze Age, agropastoralists rich in R1a and steppe ancestry replaced hunter-gatherers rich in R1b and with no steppe ancestry. Of course, that's not where the story ends, but I'll get back to that later this year.

By the way, the relatively high coverage Fatyanovo Y-chromosome sequences are being analyzed at YFull. You can check out the results here.

See also...

Sunday, January 17, 2021

A tantalizing link

A new paper at PLoS ONE reports on the first human genomes reliably associated with the Single Grave culture (SGC). They were sequenced from remains in a burial at Gjerrild, Denmark, roughly dating to 2,500 BCE.

Surprisingly, one of the male genomes belongs to Y-haplogroup R1b-V1636, which is an exceedingly rare marker both in ancient and present-day populations.

However, the results do make sense, because the earliest instances of R1b-V1636 are in three Eneolithic males from burial sites on the Pontic-Caspian (PC) steppe in Eastern Europe, which is precisely where one would expect to find the paternal ancestors of the SGC population. The SGC, of course, is the westernmost variant of the Corded Ware culture (CWC), and there's very little doubt nowadays that the CWC had its roots on the PC steppe.

A Copper Age individual from Arslantepe in central Anatolia also belongs to R1b-V1636, which suggests that Northern Europe shared a very specific link with Anatolia via Eastern Europe during a period generally regarded to have been the time of early Indo-European dispersals.

Numerous SGC barrows or kurgans dot the landscape in what are now the Netherlands, northwestern Germany and Denmark. Unfortunately, most SGC human remains have been eaten up by the acidic soils that exist in this area.

Citation: Egfjord AF-H, Margaryan A, Fischer A, Sjögren K-G, Price TD, Johannsen NN, et al. (2021) Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark. PLoS ONE 16(1): e0244872.

See also...

Maykop ancestry in Copper Age Arslantepe

That old chestnut: Northeast vs Northwest Euros

In the last comment thread reader Greg put forth this question:

David, when are you going to explain the genetic discrepancy between Northeastern and Northwestern Europeans? You know, the one that people believe is due to Baltic Hunter-Gatherer admixture, whereas you believe it is due to genetic drift? You ought to make a post about this issue at some point, because a lot of people are wondering what's causing the differences.

Well, Greg, this issue has been discussed to the proverbial death here and elsewhere. In fact, there were two posts and rather lengthy comment threads on the same topic at this blog just a few months ago. See here and here.

Nevertheless, it seems that a fair number of people are still befuddled, so I'm going to try to explain this one last time, as briefly as a I can using just a handful of f4-stats.

Admittedly, Northeast Europeans generally do pack higher levels of indigenous European hunter-gatherer ancestry than Northwest Europeans. This is especially true of Balts, who show more of this type of ancestry than even Scandinavians in practically every type of analysis.

The f4-stats below back this up unambiguously. Note the significantly positive (>3) Z scores, which suggest that Latvians and Lithuanians harbor more Baltic hunter-gatherer-related ancestry than Norwegians and Swedes.

Chimp Baltic_HG Norwegian Latvian 0.001301 7.114
Chimp Baltic_HG Swedish Latvian 0.001017 4.205
Chimp Baltic_HG Norwegian Lithuanian 0.001023 7.341
Chimp Baltic_HG Swedish Lithuanian 0.000763 3.408

Greg, I know what you're thinking: the naysayers are right! But wait, because there's a twist to this tale. Check out these f4-stats:

Chimp Baltic_HG Norwegian Belarusian 0.000265 1.934
Chimp Baltic_HG Swedish Belarusian 0.000152 0.7
Chimp Baltic_HG Norwegian Polish 6.4E-05 0.519
Chimp Baltic_HG Swedish Polish -0.000235 -1.074

Please note, Greg, that none of the Z scores reach significance, which means that these Northwest Europeans and Slavs are symmetrically related to Baltic_HG. They're also symmetrically related to other relevant ancient groups such as the Yamnaya steppe herders. This, of course, suggests that they harbor very similar levels of basically the same ancient genetic components.

Chimp Karelia_HG Norwegian Belarusian 0.000136 0.844
Chimp Karelia_HG Swedish Belarusian 7.9E-05 0.32
Chimp Karelia_HG Norwegian Polish -4.7E-05 -0.304
Chimp Karelia_HG Swedish Polish -0.000134 -0.54

Chimp Yamnaya_Samara Norwegian Belarusian -0.000134 -1.085
Chimp Yamnaya_Samara Swedish Belarusian -6.6E-05 -0.34
Chimp Yamnaya_Samara Norwegian Polish -0.000225 -1.995
Chimp Yamnaya_Samara Swedish Polish -0.000311 -1.574

Chimp Barcin_N Norwegian Belarusian -0.000335 -2.809
Chimp Barcin_N Swedish Belarusian -0.000284 -1.491
Chimp Barcin_N Norwegian Polish -0.000222 -2.057
Chimp Barcin_N Swedish Polish -0.000318 -1.662

Chimp Baikal_N Norwegian Belarusian 0.000186 1.3
Chimp Baikal_N Swedish Belarusian -7E-05 -0.33
Chimp Baikal_N Norwegian Polish -4.6E-05 -0.351
Chimp Baikal_N Swedish Polish -0.000477 -2.277

Interestingly, pairing up Ukrainians with English samples from Cornwall and Kent produces similar outcomes. But that's because most ancient ancestry proportions in Europe show a closer correlation with latitude than longitude.

Chimp Baltic_HG English_Cornwall Ukrainian 0.000282 2.242
Chimp Baltic_HG English_Kent Ukrainian 0.000225 1.748

Chimp Karelia_HG English_Cornwall Ukrainian 0.000323 2.175
Chimp Karelia_HG English_Kent Ukrainian 0.000239 1.634

Chimp Yamnaya_Samara English_Cornwall Ukrainian -6.6E-05 -0.569
Chimp Yamnaya_Samara English_Kent Ukrainian -0.000112 -0.977

Chimp Barcin_N English_Cornwall Ukrainian -0.000519 -4.641
Chimp Barcin_N English_Kent Ukrainian -0.000598 -5.232

Chimp Baikal_N English_Cornwall Ukrainian 0.000385 2.874
Chimp Baikal_N English_Kent Ukrainian 0.00036 2.836

Now, Greg, if at least in terms of genetic ancestry, Latvians, Lithuanians, Belarusians, Poles and Ukrainians all qualify as Northeast Europeans, then what makes them different, as a group, from Northwest Europeans? Do you believe that the key factor is admixture from Baltic hunter-gatherers? Or is it genetic drift?

Of course, considering all of the f4-stats above, logic dictates that it must be relatively recent genetic drift.

Keep in mind, however, that this only applies to Balto-Slavic speaking Northeast Europeans without significant Uralian ancestry. Overall, Uralic speakers have a more complex population history, and indeed genetic differences between them and Northwest Europeans are in large part due to somewhat different ancestry proportions and also Siberian admixture.

See also...

So who's the most (indigenous) European of us all?