High-resolution stuff

I just emailed this to the authors of High-resolution genomic ancestry reveals mobility in early medieval Europe, a new preprint at bioRxiv [LINK].

I appreciate that Polish population history is not the main focus of your preprint, and also that you're constrained by the lack of relevant and suitably high quality ancient genomes from East-Central and Eastern Europe. However, I must say that your analysis of the Medieval Polish population and resulting conclusions about Polish population history don't reflect reality.

Your Poland_Middle_Ages genomic cluster is made up of just six samples that don't fully represent the genetic complexity of the core population of Medieval Poland.

As a result, you classified PCA0148 as one of the Poland_Middle_Ages outliers, even though this sample isn't an outlier when analyzed within the context of the full set of published Polish Medieval genomes.

Moreover, PCA0148 is very similar to several Polish Viking Age samples that show Scandinavian-specific genome-wide and Y-chromosome haplotypes, and probably likewise shows some Scandinavian-related ancestry.

This is important to note when attempting to recapitulate Polish population history, because it suggests that Scandinavian-related ancestry played a formative role in the shaping of the core Polish Medieval genetic cluster.

Thus, you might be correct when you claim that the six samples in your Poland_Middle_Ages cluster don't show any "detectable" Scandinavian-related ancestry, but this doesn't necessarily mean that this type of ancestry isn't a key part of the post-Iron Age Polish population history.

Below is a self-explanatory Principal Component Analysis (PCA) plot that illustrates my points. Interestingly, Figure 3c in your preprint shows very similar outcomes in regards to the post-Iron Age Polish population history. But the style and scale of your figure makes it difficult to spot the subtle but likely genuine Northwest European-related genetic shifts shown by PCA0148, the Viking context samples and present-day Poles relative to the Poland_Middle_Ages cluster.

However, I'm also skeptical that your Poland_Middle_Ages cluster doesn't carry any detectable or even significant Scandinavian-related ancestry. That's because I suspect that there might be some technical issues with your analysis that are masking this type of ancestry in the Polish samples.

Your top mixture model for the Poland_Middle_Ages cluster is, in all likelihood, an extreme statistical abstraction of reality, rather than a close reflection of it. That's because, due to a combination of historical, geographical and genetic factors, neither Italy.Imperial(I).SG nor Lithuania.IronRoman.SG are realistic formative source populations for the Medieval Polish gene pool.

One of the reasons why you ended up with such a surprising result is probably the lack of suitable samples from East-Central and Eastern Europe, especially those associated with plausibly the earliest Slavic-speaking populations.

It's also possible that basing your mixture model on formal statistics played a key part.

Formal statistics-based mixture models are known to be biased towards outcomes involving mixture sources from the extremes of mixture clines. If your analysis is affected by this problem, then this would help to explain why you characterized the Poland_Middle_Ages cluster as simply a two-way mixture between a Middle Eastern-related group from Imperial Rome and a Baltic population with a very high cut of European hunter-gatherer ancestry.

I do note that on page 6 of your manuscript you consider the possibility that the Southern European-related signal in the Poland_Middle_Ages cluster might only be very distantly related to Italy.Imperial(I).SG, and that it may even have spread across Poland with early Slavic speakers. This is a great point, and I think it should be emphasized and expanded upon, because I suspect that the problem runs deeper than this.

For instance, if the early Slavic ancestors of Poles carried substantially more Southern European-related ancestry than Lithuania.IronRoman.SG, and this ancestry was, say, more Balkan-related than Italian-related, then this might radically change your modeling of the Poland_Middle_Ages cluster. That's because these early Slavs would be positioned in a very different genetic space than Lithuania.IronRoman.SG, which could potentially require a significant signal of Scandinavian-related ancestry to get a robust mixture model.

Finally, it might be useful to consider Isolation-by-Distance as a partial vector for the Italy.Imperial(I).SG-related signal in Medieval Poland.

The full set of published Polish Medieval genomes includes a number of outliers with obvious ancestry from Western Europe and the Balkans. These people probably don't represent any large-scale migrations into Poland, but rather the movements of individuals and small groups. Over time, such small-scale mobility may have had a fairly significant impact on the genetic character of the Polish population.

Update 26/03/2024: I sent another email to Speidel et al., this time in regards to their analysis of present-day Hungarians.

Your preprint also claims that present-day Hungarians are genetically similar to Scythians, and that this is consistent with the arrival of Magyars, Avars and other eastern groups in this part of Europe.

However, present-day Hungarians are overwhelmingly derived from Slavic and German peasants from near Hungary. This is not a controversial claim on my part; it's backed up by historical sources and a wide range of genetic analyses.

Hungarians still show some minor ancestry from Hungarian Conquerors (early Magyars), but this signal only reliably shows up in large surveys of Y-chromosome samples.

The Scythians that you used to model the ancestry of present-day Hungarians are of local, Pannonian origin, and they don't show any eastern nomad ancestry. So they're either acculturated Scythians, or, more likely, wrongly classified as Scythians by archeologists.

And since these so-called Scythians lack eastern nomad ancestry, the similarity between them and present-day Hungarians is not a sign of the impact from Avars, Hungarian Conquerors and the like, but rather a lack of significant input from such groups in present-day Hungarians.

Citation...

Speidel et al., High-resolution genomic ancestry reveals mobility in early medieval Europe, bioRxiv, Posted March 19, 2024, doi: https://doi.org/10.1101/2024.03.15.585102

See also...

Wielbark Goths were overwhelmingly of Scandinavian origin

Berkeley, we have a problem

A new preprint at bioRxiv by Kerdoncuff et al. makes the following, somewhat surprising, claim:

One of the individuals, referred to Sarazm_EN_1 (I4290) described above that was discovered with shell bangles showing affiliation with South Asia, has significant amount AHG-related ancestry, while a model without AHG-related ancestry provides the best fit for Sarazm_EN_2 (I4210) (Table S4.5).

First of all, the authors are actually referring to sample ID I4910 not I4210.

The aforementioned table, based on qpAdm output, shows that I4290 has 15.9% AHG-related ancestry and basically no Anatolian farmer-related ancestry. It also shows that I4910 has no AHG-related ancestry but 17.9% Anatolian farmer-related ancestry.

AHG stands for Andaman hunter-gatherer. The authors are using it as a proxy for South Asian hunter-gatherer ancestry.

However, I've looked at I4290 and I4910 in great detail over the years using ADMIXTURE, Principal Component Analysis (PCA), and qpAdm. And I'm quite certain that they do not show any obvious, above noise level South Asian ancestry. Indeed, I'd say that if they do have some minor South Asian ancestry, then I4910 probably has more of it than I4290.

Kerdoncuff et al. used the following "right pops" or outgroups: Ethiopia_4500BP.SG, WEHG, EEHG, ESHG, Dai.DG, Russia_Ust_Ishim_HG.DG, Iran_Mesolithic_BeltCave and Israel_Natufian.

This means they mixed data that were generated in very different ways (DG, SG and capture) and included some poor quality samples. For instance, the highest coverage version of Iran_Mesolithic_BeltCave offers just ~50K SNPs.

Mixing different types of data and relying on low coverage samples, even in part, often has negative consequences when using qpAdm. So I suspect that the above mentioned mixture results for I4290 are skewed by a poor choice of outgroups.

When I run qpAdm I try to stick to one type of data and avoid low quality singletons in the outgroups. This is the best qpAdm model that I can find for Sarazm_EN:

right pops:
Cameroon_SMA
Morocco_Iberomaurusian
Israel_Natufian
Levant_N
Iran_GanjDareh_N
Turkey_N
Russia_Karelia_HG
Russia_WestSiberia_HG
Mongolia_North_N
Brazil_LapaDoSanto_9600BP

Sarazm_EN
Kazakhstan_Botai_Eneolithic 0.113±0.017
Turkmenistan_C_Geoksyur_subset 0.887±0.017
P-value 0.06392

Sarazm_EN_1 (I4290)
Kazakhstan_Botai_Eneolithic 0.129±0.021
Turkmenistan_C_Geoksyur_subset 0.871±0.021
P-value 0.11019

Sarazm_EN_2 (I4910)
Kazakhstan_Botai_Eneolithic 0.104±0.021
Turkmenistan_C_Geoksyur_subset 0.896±0.021
P-value 0.07427

Also...

Sarazm_EN
Andaman_hunter-gatherer -0.018±0.020
Kazakhstan_Botai_Eneolithic 0.123±0.019
Turkmenistan_C_Geoksyur_subset 0.895±0.020
P-value 0.0298403
(Infeasible model)

Please note that Turkmenistan_C_Geoksyur_subset is made up of just three relatively high quality individuals: I8504, I12483 and I12487. That's because it's not possible to model the ancestry of Sarazm_EN using the full Geoksyur set, probably due to subtle genetic substructures within the latter.

Below is a PCA plot that, more or less, reflects my qpAdm model. I4290 and I4910 are sitting right next to each other in a cluster of ancient Central and Western Asians, and it's actually I4910 that is shifted slightly towards the South Asian pole of the PCA. Indeed, I can confidently say that there's no way to design a PCA in which I4290 is shifted significantly towards South Asia relative to I4910.

Citation...

Kerdoncuff et al., 50,000 years of Evolutionary History of India: Insights from ∼2,700 Whole Genome Sequences, bioRxiv, posted February 20, 2024, doi: https://doi.org/10.1101/2024.02.15.580575

See also...

The Nalchik surprise

A comedy of errors

The Nalchik surprise

If, like Iosif Lazaridis, you subscribe to the idea that the Yamnaya people carry early Anatolian farmer-related admixture that spread into Eastern Europe via the Caucasus, then I've got great news for you.

We now have a human sample from the Eneolithic site of Nalchik in the North Caucasus, labeled NL122, that packs well over a quarter of this type of ancestry (see here). Below is a quick G25/Vahaduo model to illustrate the point (please note that Turkey_N = early Anatolian farmers).

Target: Nalchik_Eneolithic:NL122
Distance: 2.1934% / 0.02193447
60.8 Russia_Steppe_Eneolithic
26.2 Turkey_N
13.0 Georgia_Kotias

On the other hand, if, again like Iosif Lazaridis, you subscribe to the idea that the Indo-European language spread into Eastern Europe via the Caucasus in association with this early Anatolian farmer-related admixture, then I've got terrible news for you.

That's because NL122 is apparently dated to a whopping 5197-4850 BCE (see here). This dating might be somewhat bloated, possibly due to what's known as the reservoir effect, because the Nalchik archeological site is generally carbon dated to 4840–4820 BCE.

However, even with the younger dating, this would still mean that early Anatolian farmer-related ancestry arrived in the North Caucasus, and thus in Eastern Europe, around 4,800 BCE at the latest. That's surprisingly early, and just too early to be relevant to any sort of Indo-European expansion from a necessarily even earlier Proto-Indo-Anatolian homeland somewhere south of the Caucasus.

This means that NL122 effectively debunks Iosif Lazaridis' Indo-Anatolian hypothesis. Unless, that is, Iosif can provide evidence for a more convoluted scenario, in which there are at least two early Anatolian farmer-related expansions into Eastern Europe via the Caucasus, and the expansion relevant to the arrival of Indo-European speech came well after 5,000 BCE.

I haven't done any detailed analyses of NL122 with formal stats and qpAdm. But my G25/Vahaduo runs suggest that it might be possible to model the ancestry of the Yamnaya people with around 10% admixture from a population similar to NL122.

Target: Russia_Samara_EBA_Yamnaya
Distance: 3.4123% / 0.03412328
72.6 Russia_Progress_Eneolithic
18.2 Ukraine_N
9.2 Nalchik_Eneolithic

However, I don't subscribe to the idea that the Yamnaya people carry early Anatolian farmer-related admixture that spread into Eastern Europe via the Caucasus (on top of what is already found in Progress Eneolithic). Based on basic logic and a wide range of my own analyses, I believe that they acquired this type of ancestry from early European farmers, probably associated with the Trypillia culture. For instance...

Target: Russia_Samara_EBA_Yamnaya
Distance: 3.2481% / 0.03248061
80.2 Russia_Progress_Eneolithic
13.6 Ukraine_Neolithic
6.2 Ukraine_VertebaCave_MLTrypillia
0.0 Nalchik_Eneolithic

Another way to show this is with a Principal Component Analysis (PCA) that highlights a Yamnaya cline made up of the Yamnaya, Steppe Eneolithic and Ukraine Neolithic samples. As you can see, dear reader, there's no special relationship between the Yamnaya cline and Nalchik_Eneolithic. The Yamnaya samples, which are sitting near the eastern end of the Yamnaya cline, instead seem to show a subtle shift towards the Trypillian farmers.

Indeed, I also don't exactly understand the recent infatuation among many academics, especially Iosif Lazaridis and his colleagues, with trying to put the Proto-Indo-Anatolian homeland somewhere south of the Caucasus. Considering all of the available multidisciplinary data, I'd say it still makes perfect sense to put it in the Sredny Stog culture of the North Pontic steppe, in what is now Ukraine.

Please note that all of the G25 coordinates used in my models and the PCA are available HERE.

See also...

The Caucasus is a semipermeable barrier to gene flow

Romans and Slavs in the Balkans (Olalde et al. 2023)

It's always amusing to see some random Jovan or Dimitar arguing online that Slavic speakers have been in the Balkans since at least the Neolithic.

Obviously, Slavic peoples only turned up in the Balkans during the early Middle Ages. It's just that their linguistic and genetic impact on the region was so profound that it may seem like they've been there forever.

A new paper at Cell by Olalde et al. makes this point well. See here.

That's not to say, however, that it's an ideal effort. The paper's qpAdm mixture models probably could've been more precise and realistic. Genes of the Ancients has a useful discussion on the topic here.

Interestingly, Olalde et al. admit that they can't detect much, if any, admixture from the Italian Peninsula in the Balkans, even in samples dating to the Roman period. And yet, this doesn't stop them from accepting that the Roman Empire had a massive cultural and demographic impact on the Balkans.

I also assume that, by extension, they don't deny that Latin was introduced into the Balkans from the Italian Peninsula.

That is, Latin spread into the Balkans without any noticeable genetic tracer dye, and it eventually gave rise to modern Romanian spoken by millions of people today in the eastern Balkans. This might be a useful data point to keep in mind when discussing the spread of Indo-European languages into Anatolia.

See also...

Dear Iosif, about that ~2%

Dear Harald #2

The ancIBD method paper from the David Reich Lab was just published in Nature (open access here). It's a very useful effort, but the authors are still somewhat confused about the origin of the Corded Ware culture (CWC) population. From the paper (emphasis is mine):

This direct evidence that most Corded Ware ancestry must have genealogical links to people associated with Yamnaya culture spanning on the order of at most a few hundred years is inconsistent with the hypothesis that the Steppe-like ancestry in the Corded Ware primarily reflects an origin in as-of-now unsampled cultures genetically similar to the Yamnaya but related to them only a millennium earlier.

This is basically a straw man argument, because it's easy to debunk. So why put it in the paper? Well, as far as I can see, to make the idea that the CWC is derived from Yamnaya look more plausible.

This idea, that the CWC is an offshoot of Yamnaya, seems to be the favorite explanation for the appearance of the CWC among the scientists at the David Reich Lab.

However, I'd say they're facing a major problem with that, because the CWC and Yamnaya populations have largely different paternal origins. That is, CWC males mostly belong to Y-haplogroups R1a-M417 and R1b-L51, while Yamnaya males almost exclusively belong to Y-haplogroup R1b-Z2103.

Indeed, as far as I know, there are no reliable instances of R1a-M417 or R1b-L51 in any published or yet to be published Yamnaya samples.

But it is possible to reconcile the Y-haplogroup data with the ancIBD results if we assume that the peoples associated with the Corded Ware, Yamnaya and also Afanasievo cultures expanded from a genetically more diverse ancestral gene pool, each taking a specific subset of the variation with them.

This gene pool would've existed somewhere in Eastern Europe, probably at the western end of the Pontic-Caspian steppe, at most a few hundred years before the appearance of the earliest CWC burials in what is now Poland.

Moreover, the split between the CWC and Yamnaya populations need not have been a clean one, with long-range contacts and largely female-mediated mixing maintained for generations, adding to the already close genealogical links between them.

Citation...

Ringbauer, H., Huang, Y., Akbari, A. et al. Accurate detection of identity-by-descent segments in human ancient DNA. Nat Genet (2023). https://doi.org/10.1038/s41588-023-01582-w

See also...

On the origin of the Corded Ware people

Musaeum Scythia on the Seima-Turbino Phenomenon

A few weeks ago bioRxiv published two preprints on the Seima-Turbino Phenomenon (see here and here).

I can't say much about these manuscripts until I see the relevant ancient DNA samples, and that might take some time.

However, for now, I will say that both preprints really need to emphasize the profound impact that the Sintashta-related early Indo-Iranian speakers had on the Seima-Turbino Phenomenon. This, of course, would require Wolfgang Haak and friends to pull their heads out of their behinds and admit that the proto-Indo-Iranian homeland was in Eastern Europe, not in Iran.

At the same time, it's likely that the Seima-Turbino Phenomenon originated deep in Siberia, and its inception was probably most closely associated with the West Siberian Hunter-Gatherer (WSHG) genetic component. It's important that the preprints emphasize this too.

Moreover, I can't see any convincing arguments in either preprint that the Seima-Turbino Phenomenon was mainly associated with proto-Uralic speakers, or even that it was an important vector for the spread of proto-Uralic. So there's not much point in forcing the Uralic angle on studies focused on the Seima-Turbino Phenomenon. Indeed, what we also need is an archaeogenetics paper dealing specifically with the proto-Uralic expansion.

Apart from that, I'd like to direct your attention to the fact that Musaeum Scythia has already written a fine blog post about these preprints:

Genomic insights into the Seima-Turbino Phenomenon

See also...

Finally, a proto-Uralic genome

The Uralic cline with kra001 - no projection this time

Slavs have little, if any, Scytho-Sarmatian ancestry

Wielbark Goths were overwhelmingly of Scandinavian origin

When used properly, Principal Component Analysis (PCA) is an extraordinarily powerful tool and one of the best ways to study fine-scale genetic substructures within Europe.

The PCA plot below is based on Global25 data and focuses on the genetic relationship between Wielbark Goths and Medieval Poles, including from the Viking Age, in the context of present-day European genetic variation.

I'd say that it's a wonderfully self-explanatory plot, but here are some key observations:

- the Wielbark Goths (Poland_Wielbark_IA) and Medieval Poles (Poland_Middle_Ages) are two distinct populations

- moreover, the Wielbark Goths form a relatively compact Scandinavian-related cluster and must surely represent a homogenous population overwhelmingly of Scandinavian origin

- on the other hand, the Medieval Poles form a more extensive and heterogeneous cluster that overlaps with present-day groups all the way from Central Europe to the East Baltic, and that's because they are likely to be in large part of mixed origin

- I know for a fact that at least some of these early Poles harbor recent admixture, because their burials are similar to those of Vikings and their haplotypes have been shown to be partly of Scandinavian origin (see here)

- one of the Wielbark females is an obvious genetic outlier (Poland_Wielbark_IA_outlier), and basically looks like a first generation mixture between a Goth and a Balt.

Please note that the PCA is only based on relatively high quality genomes, so as not to confuse the picture with spurious results and noise. Also, all outliers with potentially significant ancestry from outside of Central, Eastern and Northern Europe were removed from the analysis. The relevant datasheet is available here.

However, sanity checks are always important when studying complex topics like fine-scale genetic ancestry. To that end I've prepared a graph based on f3-statistics of the form f3(X,Cameroon_SMA,Estonia_BA)/(X,Cameroon_SMA,Ireland_Megalithic), that reproduces the key features of my PCA. The relevant datasheet is available here.

Polish groups from the Middle Ages are marked with the MA suffix, while the Iron Age Wielbark Goths are marked with the IA suffix.

If you're wondering why I plotted the f3-statistics that I did, take a look at this (all groups largely of Scandinavian origin are emboldened):

f3(X,Estonia_BA,Cameroon_SMA)
Poland_Legowo_MA 0.226406
Poland_Ostrow_Lednicki_MA 0.225996
Poland_Plonsk_MA 0.225017
Poland_Trzciniec_Culture 0.224215
Poland_Lad_MA 0.224142
Poland_Viking 0.223838
Poland_Niemcza_MA 0.223659
Poland_Weklice_IA 0.223549
Poland_Kowalewko_IA 0.222584
Poland_Pruszcz_Gdanski_IA 0.222324
Sweden_Viking 0.222091
Russia_Viking 0.222042
Poland_Maslomecz_IA 0.221914
Norway_Viking 0.221825
Denmark_EarlyViking 0.221257
Denmark_Viking 0.221174
England_Viking 0.220979

f3(X,Ireland_Megalithic,Cameroon_SMA)
Poland_Maslomecz_IA 0.219816
Poland_Weklice_IA 0.219501
Denmark_Viking 0.2192
Poland_Kowalewko_IA 0.219176
Poland_Ostrow_Lednicki_MA 0.218916
Norway_Viking 0.218854
Poland_Pruszcz_Gdanski_IA 0.218684
Sweden_Viking 0.218626
Denmark_EarlyViking 0.218529
England_Viking 0.218308
Russia_Viking 0.217999
Poland_Viking 0.217914
Poland_Plonsk_MA 0.217756
Poland_Lad_MA 0.217719
Poland_Legowo_MA 0.21765
Poland_Niemcza_MA 0.217001
Poland_Trzciniec_Culture 0.216551

Interestingly, the Middle Bronze Age samples associated with the Trzciniec Culture (Poland_Trzciniec_Culture) show a closer genetic relationship to Medieval Poles than to Wielbark Goths or Northwestern Europeans. This is indeed the case both in terms of genome-wide and uniparental markers, including some very specific lineages under Y-chromosome haplogroup R1a.

But that's a much more complex issue that I'll leave for another time. So please stay tuned.

See also...

Slavs have little, if any, Scytho-Sarmatian ancestry

Slavs have little, if any, Scytho-Sarmatian ancestry

Here's an abstract of a new study from the David Reich Lab about ancient Slavs, titled "Genetic identification of Slavs in Migration Period Europe using an IBD sharing graph". Emphasis is mine:

Popular methods of genetic analysis relying on allele frequencies such as PCA, ADMIXTURE and qpAdm are not suitable for distinguishing many populations that were important historical actors in the Migration Period Europe. For instance, differentiating Slavic, Germanic, and Celtic people is very difficult relying on these methods, but very helpful for archaeologists given a large proportion of graves with no inventory and frequent adoption of a different culture. To overcome these problems, we applied a method based on autosomal haplotypes. Imputation of missing genotypes and phasing was performed according to a protocol by Rubinacci et al. (2021), and IBD inference was done for ancient Eurasian individuals with data available at >600,000 1240K sites. IBD links for a subset of these individuals were represented as a graph, visualized with a force-directed layout algorithm, and clusters in this graph are inferred with the Leiden algorithm. One of the clusters in the IBD graph emerged that includes nearly all individuals in the dataset annotated archaeologically as “Slavic”. According to PCA a hypothesis for the origin of this population can be proposed: it was formed by admixture of a Baltic-related group with East Germanic people and Sarmatians or Scythians. The individuals belonging to the “Slavic” IBD sharing cluster form a chronological gradient on the PCA plot, with the earliest samples close to the Baltic LBA/EIA group. Later “Slavic” individuals are shifted to the right, closer to Central and Southern Europeans and probably reflecting further admixture of Slavs with local populations during the Migration Period.

Apparently this abstract is causing a bit of confusion online because of the mention of possible Sarmatian or Scythian ancestry in Slavs.

However, it's important to understand that the authors are referring to certain Slavic or even just Slavic-related individuals, usually from culturally heterogeneous frontier settlements deep in what is now Russia.

So yes, it's possible that some of these individuals carry Sarmatian, Scythian or other exotic eastern ancestry. But even if this is true, then obviously we can't extend this inference to all ancient and modern-day Slavs.

Indeed, below is a G25/Vahaduo Principal Component Analysis (PCA) that shows why modern-day Slavic speakers can't be linked genetically to Sarmatians or Scythians. To experience a more detailed version of the PCA paste the data here into the relevant field here.

As you can see, dear reader, most of the Slavs (Belarusians, Poles, Ukrainians and many Russians) cluster with the Irish near the western end of the plot.

Some Russians are shifted significantly east of them along the "Uralic cline" and, as a result, they cluster with various Uralic speakers such as Mordovians. That's because when Slavs migrated deep into what is now northern Russia they mixed with Uralic speakers who were there before them.

Most of the Sarmatians and Scythians form a cluster southeast of the Slavs and Irish because they carry significant levels of East Asian ancestry. This type of eastern ancestry is basically missing in modern-day Slavs (see here).

Several of the Scythians cluster among the Slavs and Irish, but that's because they're genetic outliers, whose existence, if anything, suggests that some Scythians had significant Slavic-related and/or Irish-related ancestry.

Now, even though most of the Slavs do cluster with the Irish in the above PCA plot, I strongly disagree with the authors of the abstract when they claim that "differentiating Slavic, Germanic, and Celtic people is very difficult" with PCA. It's actually pretty damn easy and I've been doing it successfully for many years. For instance, see here.

See also...

Wielbark Goths were overwhelmingly of Scandinavian origin

The Caucasus is a semipermeable barrier to gene flow

The story of the Khvalynsk people

I'm totally serious when I say that this video is more objective, informative and accurate than any peer-reviewed paper published to date when it comes to the genetic origins of the Khvalynsk people.

However, that's not to say it's perfect. I think it misses some important details. See here...

The Caucasus is a semipermeable barrier to gene flow

Dear David, Nick, Iosif...let's set the record straight

Understanding the Eneolithic steppe

Indo-European crackpottery

I've now had the chance to read and digest the following two papers in Science about the origin of Indo-European languages:

Language trees with sampled ancestors support a hybrid model for the origin of Indo-European languages, Heggarty et al.

The genetic history of the Southern Arc: A bridge between West Asia and Europe, Lazaridis, Alpaslan-Roodenberg et al.

The Heggarty et al. paper is pure fluff. It offers nothing useful or even remotely interesting.

For instance, the authors derive some Indo-European languages in Europe from Anatolian farmers and others from Caucasus hunter-gatherers (see here). This is not just exceedingly far fetched, but also obviously forced.

Wolfgang Haak and Johannes Krause, you should be deeply ashamed of yourselves.

I've already commented extensively about the Lazaridis, Alpaslan-Roodenberg et al. paper (for example, see here). But the one thing I need to add is that this paper is what it is due to the inherent bias of some of the lead authors to push the Indo-Anatolian homeland into West Asia. I won't even bother mentioning their names, because we all know who they are.

See also...

Crazy stuff

Dear David, Nick, Iosif...let's set the record straight

The story of R-V1636

Dear Harald...

I've started analyzing the Identity-by-Descent (IBD) data from the recent Ringbauer et al. preprint (see here). Unfortunately, it'll take me a few weeks to do this properly, so I won't be able to write anything detailed on the topic for a while.

Meantime, this is the comment that I left for the authors at bioRxiv (at this time it's still being approved, but it should appear there within a day or so, possibly along with a reply from the authors):

Hello authors,

Thanks for the interesting preprint and data. However, I'd like to see you address a couple of technical issues and perhaps one theoretical issue in the final manuscript:

- the output you posted shows some unusual results, which are potentially false positives that appear to be concentrated among the shotgun and noUDG samples. I'm guessing that this is due to the same types of ancient DNA damage creating IBD-like patterns in these samples. If so, isn't there a risk that many or even most of the individuals in your analysis are affected by this problem to some degree, which might be skewing your estimates of genealogical relatedness between them?

- many individuals from groups that have experienced founder effects, such as Ashkenazi Jews, appear to be close genetic cousins, even though they're not genealogical cousins. Basically, the reason for this is reduced haplotype diversity in such populations. Have you considered the possibility that at least some of the close relationships that you're seeing between individuals and populations might be exaggerated by founder effects?

- thanks to ancient DNA we've learned that the Yamnaya phenomenon isn't just an archeological horizon, but also a closely related and genetically very similar group of people. Indeed, in my mind, ancient DNA has helped to redefine the Yamnaya concept, with Y-chromosome haplogroup R1b-Z2103 now being one of the key traits of the Yamnaya identity. So considering that the Corded Ware people are not rich in R1b-Z2103, and even the earliest Corded Ware individuals are somewhat different from the Yamnaya people in terms of genome-wide genetic structure, it doesn't seem right to keep claiming that the Corded Ware population is derived from Yamnaya. I can't see anything in your IBD data that would preclude the idea that the Corded Ware and Yamnaya peoples were different populations derived from the same as yet unsampled pre-Yamnaya/post-Sredny steppe group.

See also...

Dear Harald #2

On the origin of the Corded Ware people

Dear David, Nick, Iosif...let me tell you about Yamnaya

Lazaridis, Alpaslan-Roodenberg et al. recently claimed that the Yamnaya people of the Pontic-Caspian (PC) steppe carried "substantial" ancestry from what is now Armenia or surrounds.

However, this claim is essentially false.

Only one individual associated with the Yamnaya culture shows an unambiguous signal of such ancestry. This is a female usually labeled Ukraine_Yamnaya_Ozera_o:I1917. The "o" suffix indicates that she is an outlier from the main Yamnaya genetic cluster.

Unlike I1917, typical Yamnaya individuals carry a few per cent of ancient European farmer admixture. This ancestry is only very distantly Armenian-related via Neolithic Anatolia (see here).

It's difficult for me to understand how Lazaridis, Alpaslan-Roodenberg et al. missed this. I suspect that they relied too heavily on formal statistics and overinterpreted their results.

Formal statistics are a very useful tool in ancient DNA work. Unfortunately, they're also a relatively blunt tool that often has problems distinguishing between similar sources of gene flow.

There are arguably better methods for studying fine scale ancestry, such as Principal Component Analysis (PCA).

Below is a somewhat special PCA featuring a wide range of ancient populations that plausibly might be relevant to the genetic origins of the Yamnaya people. Unlike most PCA with ancient samples, this PCA doesn't rely on any sort of projection, so that all of the actors are interacting with each other and directly affecting the outcome.

Here's another version of the same plot with a less complicated labeling system. Note that I designed this PCA specifically to differentiate between European populations and those from the Armenian highlands, the Iranian plateau and surrounds.

And here's a close up of the part of the plot that shows the Yamnaya cluster. This cluster is made up of samples associated with the Afanasievo, Catacomb, Poltavka and Yamnaya cultures. All of the individuals in this part of the plot are closely related, which is why they're so tightly packed together. The differentiation between them is caused by admixture from different groups mostly from outside of the PC steppe.

The Yamnaya cluster can be broadly characterized as a population that formed along the genetic continuum between the Eneolithic groups of the Progress region and Neolithic foragers from the Dnieper River valley (Progress_Eneolithic and Ukraine_N, respectively). However, this cluster also shows a slight western shift that is increasingly more pronounced in the Corded Ware samples. This shift is due to the aforementioned admixture from early European farmers.

Indeed, the plot reveals two parallel clines extending west from the Progress samples. One of the clines is made up of the Yamnaya cluster and the Corded Ware samples, and pulls towards the ancient European farmers. The other cline includes Ukraine_Yamnaya_Ozera_o:I1917 and pulls towards samples from the Armenian highlands and surrounds.

Being aware of these two clines and knowing how they came about is important to understanding the genetic prehistory of the PC steppe and indeed of much of Eurasia.

At some point, probably during the late Eneolithic, a Progress-related group experienced gene flow from the west and became the Yamnaya and Corded Ware populations. Sporadically, admixture from the Armenian highlands and the Iranian plateau also entered the PC steppe, giving rise to people like the Steppe Maykop outliers and Ukraine_Yamnaya_Ozera_o:I1917.

Unfortunately, this sort of PCA doesn't offer output suitable for mixture modeling, basically because the recent genetic drift shared by many of the samples creates significant noise.

However, to check that my inferences based on the plot are correct I can create composites with specific ancestry proportions to see how they behave. In the plot below Mix1 is 80% Progress_Eneolithic and 20% Iran_Hajji_Firuz_N, Mix2 is 80% Progress_Eneolithic and 20% Armenia_EBA_Kura_Araxes, while Mix3 is 80% Progress_Eneolithic, 15% Ukraine_N and 5% Hungary_MN_Vinca (Middle Neolithic farmers from the Carpathian Basin).

Obviously, we can't get Yamnaya by mixing Progress_Eneolithic with any ancients from the Armenian highlands or the Iranian plateau. On the other hand, Mix3 works quite well, at least in the first two dimensions. In some of the other dimensions genetic drift specific to Ukraine_N pulls it away from the Yamnaya cluster, but this is to be expected.

By the way, the plots were created with the excellent Vahaduo Custom PCA tool freely available here. It's well worth trying the interactive 3D option using my PCA data. The relevant datasheet is available here.

See also...

Dear David, Nick, Iosif...let's set the record straight

The Caucasus is a semipermeable barrier to gene flow

Dear David, Nick, Iosif...let's set the record straight

Almost a decade ago scientists at the David Reich Lab extracted DNA from the remains of three men from the Khvalynsk II cemetery at the northern end of the Pontic-Caspian (PC) steppe.

These Eneolithic Eastern Europeans showed significant genetic heterogeneity, with highly variable levels of Eastern Hunter-Gatherer (EHG) and Near Eastern-related ancestry components.

As a result, the people at the David Reich Lab concluded that the Eneolithic populations of the PC steppe formed from a relatively recent admixture between local hunter-gatherers and Near Eastern migrants.

Unfortunately, this view has since become the consensus among scientists working with ancient DNA.

I say unfortunately because there's a more straightforward and indeed obvious explanation for the genetic heterogeneity among the samples from Khvalynsk II. It's also the only correct explanation, and it doesn't involve any recent gene flow from the Near East.

Here it is, in point form, as simply as I can put it:

- EHG is best represented by samples from Karelia and Lebyazhinka, which are modern-day Russian localities in the forest zone and on the border between the steppe and the forest-steppe, respectively

- Khvalynsk II is also located on the boundary between the steppe and the forest-steppe, and very far from the Near East

- so the genetic structure of the people buried at Khvalynsk II does represent an admixture event

- however, this admixture event simply involved an EHG population from the forest-steppe and a very distantly Near Eastern-related group native to the steppe (that is, two different Eastern European populations).

I've written this blog post because I think David Reich, Nick Patterson, Iosif Lazaridis and colleagues should finally admit that they didn't quite get this right. And it'd be nice if they could put out a paper sometime soon in which they set the record straight.

See also...

A reappraisal of Ashkenazic maternal ancestry

Kevin Brook, who occasionally comments on this blog, has published a peer-reviewed book titled The Maternal Genetic Lineages of Ashkenazic Jews.

The book focuses on 129 mitochondrial (mtDNA) haplogroups that are found in present-day Ashkenazic Jews, and reveals that these lineages can be traced back to a wide range of places, such as Israel, Italy, Poland, Germany, North Africa, and China.

Ergo, it argues that both Israelites and converts to Judaism from a variety of gentile groups made lasting contributions to the Ashkenazic maternal gene pool. In Kevin's own words, the book also:

- shows that all Ashkenazim remain genetically linked to a significant degree to other types of Jewish populations, not only paternally but maternally as well

- disproves the myth that Cossack rapists were responsible for any of the non-Israelite DNA in Ashkenazim

- presents new DNA evidence in favor of a small contribution of Khazarian and Alan converts to Judaism to the Ashkenazic gene pool.

That makes good sense based on what I've learned over the years from studying modern and ancient genome-wide Ashkenazic DNA. More information about Kevin's book is available at the Khazaria.com website HERE.

See also...

My take on the Erfurt Jews

The Kura-Araxes people deserve better

When discussing the Kura-Araxes culture and its people it's important to understand these key points:

- there is Eastern European steppe ancestry in Kura-Araxes samples, and if you're not seeing it then you're not looking hard enough

- Armenian Kura-Araxes samples are mainly a mixture between three different groups currently best represented in the ancient DNA record by ARM_Areni_C, IRN_Hajji_Firuz_C and RUS_Darkveti-Meshoko_En

- ergo, most of the steppe ancestry in the Kura-Araxes population of what is now Armenia must have been mediated via local Chalcolithic groups like ARM_Areni_C

- Kura-Araxes samples show Mesopotamian-related ancestry, and this mustn't be ignored.

Oh, you don't believe it because you just read a big paper in Science claiming otherwise?

Well, the authors of that paper, Lazaridis, Alpaslan-Roodenberg et al., used distal mixture models to study the ancestry of their Kura-Araxes samples, and such models can miss important details.

Consider these three proximate mixture models for a relatively high quality and very homogenous Kura-Araxes sample set from the aforementioned paper. They were done with the qpAdm software

ARM_Kura-Araxes_Berkaber
ARM_Areni_C 0.239±0.068
IRN_Hajji_Firuz_C 0.379±0.068
RUS_Darkveti-Meshoko_En 0.382±0.054
P-value 0.285122 (Pass)
Full output

ARM_Kura-Araxes_Berkaber
IRN_Hajji_Firuz_C 0.569±0.051
RUS_Darkveti-Meshoko_En 0.363±0.058
RUS_Progress_En 0.068±0.020
P-value 0.20306 (Pass)
Full output

ARM_Kura-Araxes_Berkaber
IRN_Hajji_Firuz_C 0.531±0.060
RUS_Darkveti-Meshoko_En 0.469±0.060
P-value 0.0132579 (Fail)
Full output

Some caveats apply. For instance, the pass threshold (P-value ≥0.05) is arbitrary. But the point is that the models look much better with steppe-related and steppe reference populations (ARM_Areni_C and RUS_Progress_En, respectively).

Moreover, the unique and vital Darkveti-Meshoko population is represented by just one individual. I also have the genotypes of his brother and sister, but relatives aren't allowed in these sorts of tests.

Including a singleton in the analysis means that I can't use the inbreed: YES option, which apparently can be a bad thing. Nevertheless, these models do look very solid.

Indeed, I can also model ARM_Kura-Araxes_Berkaber as practically 100% RUS_Maykop_Novosvobodnaya, perhaps with some excess ARM_Areni_C-related input.

ARM_Kura-Araxes_Berkaber
ARM_Areni_C 0.094±0.087
RUS_Maykop_Novosvobodnaya 0.906±0.087
P-value 0.284259 (Pass)
Full ouput

This makes good sense, because RUS_Maykop_Novosvobodnaya can also be modeled solidly as a mixture between IRN_Hajji_Firuz_C, RUS_Darkveti-Meshoko_En and RUS_Progress_En.

RUS_Maykop_Novosvobodnaya
IRN_Hajji_Firuz_C 0.614±0.056
RUS_Darkveti-Meshoko_En 0.307±0.064
RUS_Progress_En 0.080±0.022
P-value 0.141468 (Pass)
Full output

I don't know whether the genetic relationship between ARM_Kura-Araxes_Berkaber and RUS_Maykop_Novosvobodnaya shown in my model is due to Maykop ancestry in the former. It might just be a coincidence in the sense that the same or similar processes led to the formation of both groups. Feel free to let me know your thoughts about that in the comments.

The fact that the Kura-Araxes people harbored steppe ancestry might be very important in the debate over the location of the so called Indo-Anatolian homeland. For instance, it's possible that the proto-Anatolian language spread from the North Caucasus into Anatolia via the Kura-Araxes culture.

But, admittedly, such a solution doesn't have strong support from historical linguistics data, which suggest that the Indo-Anatolian homeland was located in what is now Ukraine and that Anatolian speakers entered West Asia via the Balkans:

Indo-European cereal terminology suggests a Northwest Pontic homeland for the core Indo-European languages

See also...

R-V1636: Eneolithic steppe > Kura-Araxes?

Dear Iosif...Yamnaya

But Iosif, what about the Phrygians?

Balto-Slavs and Sarmatians in the Battle of Himera

G25 coordinates for most of the samples from the recent Reitsema et al. paper are available in a text file here. They're also in the G25 datasheets at the usual link here.

A basic distance analysis with the G25 data at Vahaduo shows that the two samples labeled Himera_480BCE_3 are either early Balts or Slavs. I suspect that they're Slavs, because I believe that early Slavs had this type of Baltic-like genetic structure before mixing with their non-Slavic-speaking neighbors. Well, that's my pet theory for now, so take it or leave it.

Distance to: ITA_Sicily_Himera_480BCE_3:I10943
0.03393838 HUN_IA_La_Tene_o:I18226
0.03572886 DEU_MA_Krakauer_Berg:KRA001
0.03618075 RUS_Pskov_VA:VK159
0.03899963 SWE_Gotland_VA:VK463
0.03915018 Baltic_EST_IA:s19_V12_1

Distance to: ITA_Sicily_Himera_480BCE_3:I10949
0.03573636 HUN_IA_La_Tene_o3:I25524
0.03698768 HUN_IA_La_Tene_o:I18226
0.03732752 SWE_Skara_VA:VK397
0.03767022 Baltic_EST_IA:s19_V12_1
0.03772687 DEU_MA_Krakauer_Berg:KRA001

On the other hand, I'm almost certain that the two Himera_480BCE_4 samples are Sarmatians. The good old G25 does it again!

Distance to: ITA_Sicily_Himera_480BCE_4:I10944
0.03100861 KAZ_Segizsay_Sarmatian:SGZ002
0.03548059 MDA_Sarmatian:I11925
0.03619219 RUS_Urals_Sarmatian:MJ56
0.03626538 RUS_Urals_Sarmatian:chy001
0.03904260 RUS_Urals_Sarmatian:MJ41

Distance to: ITA_Sicily_Himera_480BCE_4:I10947
0.02989458 RUS_Urals_Sarmatian:MJ43
0.03052790 RUS_Urals_Sarmatian:chy002
0.03170622 KAZ_Kangju:DA226
0.03288789 TUR_BlackSea_Samsun_Anc_C:I4529
0.03310149 KAZ_Aigyrly_Sarmatian:AIG003

See also...

Slavic-like Medieval Germans

Dear Iosif, about that ~2%

The debate over the location of the so called Indo-Anatolian homeland won't be decided by the persistence of any type of genetic ancestry in ancient Anatolia.

It'll be decided by a multidisciplinary study on the interactions between the ancient peoples of the North Pontic steppe, the eastern Balkans, and western Anatolia.

If such a study finds a pulse of steppe-related gene flow from the Balkans into Anatolia sometime during the early metal ages, it'll corroborate the linguistic hypothesis that a language ancestral to Hittite, Luwian and related tongues moved into Anatolia from Eastern Europe.

Why do we only need a pulse of gene flow, you might ask? Obviously, because:

- language and genetic ancestry can start with a strong association but, since they're not linked, they can eventually follow very different trajectories

- the dilution of genetic ancestry is an important factor, especially in ancient West Asia, and it must be taken into account in models of language spread, rather than ignored in favor of simple, elegant models that do not reflect reality.

Here's my favorite quote from the recent Lazaridis, Alpaslan-Roodenberg et al. paper, because, probably unbeknownst to the authors, it's exceptionally revealing about the spread of a wide range of Indo-European speakers into Anatolia.

However, in individuals from Gordion, a Central Anatolian city that was under the control of Hittites before becoming the Phrygian capital and then coming under the control of Persian and Hellenistic rulers, the proportion of Eastern hunter-gatherer ancestry is only ~2%, a tiny fraction for a region controlled by at least four different Indo-European–speaking groups.

Indeed, this is exactly what the Lazaridis, Alpaslan-Roodenberg et al. paper should've been about. That is, the authors should've given us a painstaking account of the spread of different ancient Indo-European speaking groups into Anatolia and explained how, overall, their DNA was rapidly diluted to a trace amount.

However, instead they treated us to a make-believe tale about a so called Indo-Anatolian homeland in what is now Armenia.

See also...

Dear Iosif...Yamnaya

But Iosif, what about the Phrygians?

Dear Iosif...

Dear Iosif #2

Dear Iosif #3

Dear Iosif...

Update 29/08/22: Dear Iosif #2

...


I'm skimming through the Lazaridis, Alpaslan-Roodenberg et al. paper that just came out at Science. And I feel like someone punched me in the face.

Nevertheless, I'll try to be diplomatic. Suffice to say, for now, that there's some rather strange stuff in this paper.

The main problem is that the authors are attempting to study fine scale ancestry with a somewhat rough distal model. As a result, they miss important details.

For instance, this quote is from the paper's supplementary PDF file, freely available here.

However, the complete lack of association of R-haplogroup descendants and EHG ancestry in either Armenia or Iran is consistent with either a massive dilution of EHG ancestry in these populations resulting in the dissociation of Y-chromosome lineages from autosomal ancestry over time, or with a scenario in which R-M269 was not associated with substantial EHG ancestry to begin with.

Obviously, EHG means Eastern European Hunter-Gatherer. But why focus on EHG? Surely, this makes little sense when looking at the genetic prehistory of West Asia, because no one ever argued that this region was settled by EHG populations. It was widely settled by Yamnaya-related groups, with already heavily diluted EHG ancestry, during the metal ages.

OK, so the authors are actually aware about the potential dilution of EHG ancestry, but they don't really do anything about it.

If we're looking at the origins of West Asian R1b-M269, and using its association with autosomal DNA components as a guide, then we should be focusing on Yamnaya-related ancestry.

For instance, here's a fine scale ancient ancestry model based on Principal Component Analysis (PCA) data. It shows the ancestry proportions of two relatively high coverage Iron Age males from two different sites in Iran from the Lazaridis, Alpaslan-Roodenberg et al. dataset. Both belong to R1b-M269 and both show significant Yamnaya-related ancestry.

Target: IRN_HajjiFiruz_IA:I2327_all
Distance: 2.2930% / 0.02292994
39.6 Kura-Araxes_ARM_Kaps
24.2 IRN_Ganj_Dareh_N
18.2 Levant_PPNB
12.4 Yamnaya_RUS_Samara
4.4 Anatolia_Tepecik_Ciftlik_N
1.2 Han

Target: IRN_Hasanlu_IA:I4232_all
Distance: 2.5179% / 0.02517895
26.0 IRN_Ganj_Dareh_N
25.6 Kura-Araxes_ARM_Kaps
24.4 Anatolia_Tepecik_Ciftlik_N
15.8 Yamnaya_RUS_Samara
7.6 Levant_PPNB
0.6 IRN_Shahr_I_Sokhta_BA2

As a control, here's an earlier, Chalcolithic sample bearing Y-haplogroup J2b from the same region. Not surprisingly, this individual totally lacks the Yamnaya-related signal.

Target: IRN_HajjiFiruz_ChL:I4241_all
Distance: 2.7938% / 0.02793782
32.6 Kura-Araxes_ARM_Kaps
25.6 IRN_Ganj_Dareh_N
23.6 Anatolia_Tepecik_Ciftlik_N
18.2 Levant_PPNB

Overall, these results make perfect sense. I could probably locate very minor signals of EHG ancestry in the Iron Age samples, but that would be more difficult and much less certain, so I won't bother.

Soon I'll be able to rerun these analyses with Bronze Age samples from Dagestan and surrounds. That should bump up the levels of Yamnaya-related ancestry and improve the statistical fits (wink, wink, nudge, nudge).

Disappointingly, Lazaridis, Alpaslan-Roodenberg et al. go so far as to suggest that R1b-M269 may have originated in West Asia.

However, considering the scores of ancient Eastern European populations rich in R1b-M269 and many near and far related subclades of R1b, this makes no sense whatsoever.

Indeed, contemplating nowadays that R1b-M269 might be native to West Asia, where R1b only starts showing up in the ancient DNA record during the Copper Age, is about as stupid as claiming that gravity doesn't exist.

Largely due to their distal model approach, Lazaridis, Alpaslan-Roodenberg et al. also argue that the Indo-Anatolian homeland was located in what is now Armenia and surrounds. I'm far from convinced that this solution will stand the test of time.

In terms of the more widely accepted theory that the Indo-Anatolian homeland was located on the Pontic-Caspian steppe in Eastern Europe, the most important samples in the paper are the three Bronze Age individuals from Yassitepe in western Anatolia. That's because they're from a region that is traditionally seen as the entry point of Indo-Anatolian speakers into Anatolia from the European steppe via the Balkans.

Interestingly, individual I5737, dated to 2035-1900 calBCE or the Middle Bronze Age, belongs to Y-chromosome haplogroup I2a-P78, which surely must be a signal of European ancestry. I see this as a significant result.

Here's how the trio from Yassitepe look in my fine scale ancient ancestry model. Minor Yamnaya-related ancestry does show up, although, admittedly, it might just be noise in individual I5735.

Target: TUR_Aegean_Izmir_Yassitepe_MBA:I5737
Distance: 2.7507% / 0.02750748
58.4 Anatolia_Barcin_N
20.4 Kura-Araxes_ARM_Kaps
9.2 Anatolia_Tepecik_Ciftlik_N
5.6 IRN_Ganj_Dareh_N
3.8 Yamnaya_RUS_Samara
2.6 Levant_PPNB

Target: TUR_Aegean_Izmir_Yassıtepe_EBA:I5733
Distance: 2.7969% / 0.02796887
52.0 Anatolia_Barcin_N
27.2 Kura-Araxes_ARM_Kaps
8.6 Levant_PPNB
6.2 Yamnaya_RUS_Samara
6.0 IRN_Ganj_Dareh_N

Target: TUR_Aegean_Izmir_Yassıtepe_EBA:I5735
Distance: 3.1270% / 0.03127009
36.0 Kura-Araxes_ARM_Kaps
32.4 Anatolia_Tepecik_Ciftlik_N
26.0 Anatolia_Barcin_N
2.8 IRN_Shahr_I_Sokhta_BA2
1.2 Yamnaya_RUS_Samara
1.0 Levant_PPNB
0.6 MAR_Taforalt

This isn't much, especially considering it's already late 2022, but it's better than nothing. Fortunately, more samples from Bronze Age western Anatolia are on the way (wink, wink, nudge, nudge).

However, I'm not done with the Lazaridis, Alpaslan-Roodenberg et al. dataset yet. I'm planning to spend much more time on this blog in the coming weeks and months and will be using their samples in a wide range of analyses.

Citation...

Iosif Lazaridis, Songül Alpaslan-Roodenberg et al., The genetic history of the Southern Arc:A bridge between West Asia and Europe, Science 377, eabm4247 (2022)

See also...

Dear Iosif #3

But Iosif, what about the Phrygians?

Dear Iosif, about that ~2%

Dear Iosif...Yamnaya

My take on the Erfurt Jews

I had a quick look at the genotype data from the recent Waldman et al. preprint focusing on the ancestry of early Jews from Erfurt, Germany. My impression is that the genetic origins of these Jews are somewhat more complex than claimed in the manuscript.

Indeed, I'd say the Waldman et al. characterization of the Erfurt Jews as a three-way mixture between populations similar to present-day Lebanese, South Italians and Russians doesn't exactly reflect reality.

Unlike Waldman et al., I designed an ADMIXTURE analysis that separated East Asian ancestry into East Asian and Siberian clusters, and also included Mediterranean and North African clusters. The output is available in a spreadsheet HERE. Below is a bar graph based on some of the output.

Now, keeping in mind that ADMIXTURE is not a formal mixture test, and that it estimates ancestry proportions from inferred populations, as opposed to ancient groups that actually existed, here are some key observations:

- in terms of fine scale ancestry, the Erfurt Jews show enough variation to be divided into three or four clusters, as opposed to just two as per Waldman et al.

- some of the Erfurt Jews show excess "Mediterranean" ancestry, while others excess "North African" ancestry, and this cannot be explained with ancestral populations similar to Lebanese and/or South Italians, but rather with significant gene flow from the western Mediterranean and possibly North Africa

- several of the Erfurt Jews show relatively high levels of "East Asian" ancestry that cannot be explained by admixture from Russians, or even any Russian-like populations, because such populations almost lack this type of ancestry, and instead show significant "Siberian" admixture

- as far as I can see, there are no correlations between any of the observations above and the quality of the samples. That is, low coverage doesn't appear to be causing the aforementioned excess "Mediterranean", "North African" and/or "East Asian" ancestry proportions.

Investigating this in more detail with, say, formal statistics will take some time. But I was able to reproduce the results from the above ADMIXTURE run using several somewhat different datasets, so that's something.

It seems to me that Waldman et al. want a simple and elegant model to explain the data, which is understandable, but I do think they should at least expand their ADMIXTURE analysis to include "Siberian", "Mediterranean" and "North African" clusters, and go from there depending on what they find.

Citation...

Waldman et al., Genome-wide data from medieval German Jews show that the Ashkenazi founder event pre-dated the 14th century, bioRxiv, posted May 16, 2022, doi: https://doi.org/10.1101/2022.05.13.491805

See also...

Mediterranean PCA update

Balto-Slavic drift

A few years ago I began using the term "Balto-Slavic genetic drift" to describe the fine-scale genetic signal that is shared by the speakers of Baltic and Slavic languages to the exclusion of Europeans without significant Balto-Slavic ancestry.

As a result, nowadays, many people online use the term "Balto-Slavic drift" when referring to this phenomenon.

The easiest way to prove that Balto-Slavic drift exists is to run a fine-scale Principal Component Analysis (PCA) of European genetic variation with a lot of Balto-Slavic samples in the mix. Indeed, my Global25 PCA analysis does a great job of illustrating the impact of Balto-Slavic drift on the population structure of Europe both in PCA plots and mixture models (for instance, see here).

It's also possible to tease out Balto-Slavic drift with formal statistics. I showed this indirectly in a recent blog post about Greek population structure (see here). In this post I'm going to demonstrate how to explicitly and formally test for Balto-Slavic drift both in ancient and present-day samples.

To do this we need to find stats that basically split Baltic and Slavic speakers from other Europeans, such as f4(Outgroup,Test;Bell_Beaker_NDL,Baltic_LVA_BA). In this f4-stat, Baltic_LVA_BA is the ancient reference population with an unusually high level of Balto-Slavic drift, while Bell_Beaker_NDL is a fairly similar population overall in terms of ancient ancestry components, but with practically zero Balto-Slavic drift.

Note that the statistics with the most significant Z scores (>3) involve populations that speak Baltic or Slavic languages, or their neighbors who plausibly harbor significant Baltic and/or Slavic ancestry. Among the ancient, mostly Scandinavian, populations (from Margaryan et al. 2020 and marked with the VK2020 prefix), significant Balto-Slavic drift only appears in the more easterly and/or later groups from the Viking Age (VA).

Unfortunately, one of the problems with this analysis is that Baltic_LVA_BA and Bell_Beaker_NDL aren't identical in terms of their ancient ancestry proportions. For one, the latter has significantly more Neolithic farmer ancestry. No wonder then, that Greeks, who are mostly of early farmer stock, don't show a significant Z score, despite probably packing a significant amount of Balto-Slavic ancestry dating to the Middle Ages.

In the near future, as more ancient samples become available, it might be possible to find better reference populations for the job and create more accurate, finer-scaled tests.

See also...

Uralian genes

That old chestnut: Northeast vs Northwest Euros