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Tuesday, January 22, 2019

Hungarian Yamnaya predictions

About ten thousand ancient burial mounds still stand in the Carpathian Basin and surrounds. Many of these kurgans or tumuli show direct archeological links with the highly mobile Yamnaya culture of the Pontic-Caspian steppe to the east, and may have been built by Yamnaya migrants.

The testing of ancient DNA from the remains in these burials is important, because the results are likely to be informative about the profound genetic, cultural and linguistic changes that took place in what is now Hungary and the Balkans during the Copper and Bronze Ages.

But, alas, probably to the disappointment of some readers, my great prediction is that they're not going to be overly relevant to what happened at this time in Northern and Western Europe, and won't upend the current consensus that the Corded Ware culture (CWC) was the main vector for the spread of steppe ancestry and Indo-European languages into these parts of the continent.

The important thing to understand about the Yamnaya expansion into the Carpathian Basin is that it mostly stopped at the Tisza River. It's true that some archeological cultures west of the Tisza, such as Mako and Vucedol, do show fairly strong Yamnaya influences, but they can't be regarded as part of the Yamnaya colonization of Central Europe. Below is a slightly modified map from Heyd 2011 to illustrate my point.

In fact, four early Yamnaya period samples from one of the few kurgans west of the Tisza have already been published along with the Olalde et al. 2018 paper on the Bell Beaker culture (BBC). And one of these samples, labeled I5117, even represents a male buried in a Yamnaya-like pose. But this is how three of these individuals cluster in my Principal Component Analysis (PCA) of ancient West Eurasian genetic variation.

They sit firmly among other Copper Age and Neolithic samples from west of the Pontic-Caspian steppe. In other words, they show practically zero Yamnaya-related or steppe ancestry. Moreover, both of the males belong to Y-haplogroup G2a-L91, which is yet to be found in any samples from the Copper and Bronze Age steppe.

That's not to suggest, however, that the spread of the Yamnaya culture into the Carpathian Basin was a cultural process with little or no genetic impact. It probably wasn't, because five samples labeled "Yamnaya Hungary" were featured in the Wang et al. 2018 preprint on the genetic prehistory of the Greater Caucasus, and judging by their PCA and ADMIXTURE results (in the figure below from the said preprint) they're not very different from most other Yamnaya samples, such as those from far to the east in Kalmykia or Samara.

But the point I'm making is that not every one of the ten thousand kurgans and tumuli in the Carpathian Basin and surrounds was built by newcomers from the steppe, and, thus, my other prediction is that a fair proportion of the Yamnaya-related burial mounds, especially west of the Tisza, might contain remains without any steppe ancestry.

As far as I know, the Y-haplogroups of the aforementioned Yamnaya Hungary samples haven't yet been reported anywhere. But there are three ancients in the Mathieson et al. 2018 paper on the genetic prehistory of southeastern Europe that are probably highly informative about what we can expect in this context, because based on their archeology and ancestry, they're likely to be closely related to the Hungarian Yamnaya population. They are:

Balkans_BronzeAge I2165: Y-hg I2a-L699 3020-2895 calBCE

Vucedol_Croatia I3499: Y-hg R1b-Z2103 2884-2666 calBCE

Yamnaya_Bulgaria Bul4: Y-hg I2a-L699 3012-2900 calBCE

That's not much to work with, you might say. Perhaps, but keep in mind that R1b-Z2103 has now been reported in Yamnaya samples from Ciscaucasia, Kalmykia, and Samara, and I2a-L699 in a Yamnaya singleton from Kalmykia. Thus, a lot of outcomes are still possible, but some are more likely than others. So I'm expecting most Hungarian Yamnaya males to belong to R1b-Z2103 and I2a-L699, or perhaps even the other way around!

However, in line with my great prediction, I don't expect to see any R1a-M417 or R1b-L51, the two most common Y-halogroups among present-day Europeans living north and west of the Balkans. And I think that if these markers do actually show up, then they'll be represented by nowadays rare or even extinct lineages that aren't very important to the peopling of Europe. Any thoughts? Feel free to share them in the comments.

See also...

Hungarian Yamnaya > Bell Beakers?

Single Grave > Bell Beakers

Dutch Beakers: like no other Beakers

Saturday, January 19, 2019

Dutch Beakers: like no other Beakers

In my last two blog posts I tried to explain why the so called Bell Beakers of prehistoric Europe cannot be confidently derived in any significant way from the Yamnaya population of the Carpathian Basin, and are more likely to have been an offshoot, in varying degrees, of the Single Grave or Corded Ware people of the Lower Rhine region (see here and here).

To help drive my message home, below is a series of new Principal Component Analysis (PCA) plots that illustrate the unique position of Dutch Beakers from the Lower Rhine relative to the Corded Ware population of Germany and all the other Beaker groups sampled to date. The relevant datasheet is available here.

The Dutch Beakers don't exactly sit between the Corded Ware and the other Beaker samples, but generally at the apex of their clusters, suggesting to me that they're not a mixture between Corded Ware and one or more of the other Beaker groups, but rather, as per my recent argumentation, a genetically homogeneous, relatively unique and thus long-standing Corded Ware-related population that may have contributed significant gene flow to the other Beaker groups.

Please note also that all of these outcomes can be confirmed with various types of formal statistics. I know this because I've done it.

See also...

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

Wednesday, January 16, 2019

Single Grave > Bell Beakers

I've been studying in detail the genetic substructures within the Bell Beaker population with formal statistics and Principal Component Analyses (PCA). As far as I can see, among the two most homogeneous, and thus least likely to be recently admixed, Beaker groups are the Dutch Beakers and also the Dutch and British Beaker males belonging to Y-haplogroup R1b-P312. This, of course, makes good sense, because both the Dutch and British Beakers are so called Rhenish Beakers.

The results are also in line with the observation that the Dutch Beakers are the quintessential Beakers in terms of physique, with three quarters or more sporting exceedingly brachycephalic, planoccipital skulls (like this).

Moreover, these two Beaker groups are among the most Yamnaya-like Beakers, with almost as much Yamnaya-related ancestry as the Corded Ware culture samples from Germany (~60% vs ~70%). As a result, in my PCA of ancient West Eurasian genetic variation the Dutch Beakers form a more or less continuous, west to east cline with these and other Corded Ware individuals that runs all the way to the Yamnaya cluster.

In the same PCA, the R1b-P312 Dutch and British Beaker males form a tight cluster at the apex of a Beaker cline that stretches to European Neolithic groups with no steppe ancestry. The only Beaker who is positioned clearly east of the Dutch/British R1b-P312 Beaker cluster is from Hungary, and in all likelihood he harbors recent Yamnaya ancestry because his Y-haplogroup is the Yamnaya-specific R1b-Z2103.

These findings potentially have important implications for the origins of the Dutch Beakers and the Beakers who dominated much of Central and Western Europe during the Late Neolithic and Bronze Age, and these are:

- the Dutch Beakers are unlikely to be the result of a recent migration from afar into what is now The Netherlands and surrounds, but rather the descendants, by and large, of the earlier local Single Grave (and thus Corded Ware) populations

- the R1b-P312 lineages in the Dutch and British Beakers probably derive from Single Grave R1b-P312, which suggests that R1b-P312 was common among some clans within the Corded Ware culture

- the spread of most of the Yamnaya-related or steppe ancestry and quintessential Beaker physique across the Beaker world and into Western Europe can probably be blamed on the massive expansions of Beakers from what is now The Netherlands and surrounds (ie. the Lower Rhine region)

- late Yamnaya groups contributed some ancestry to eastern Beaker groups, such as those in the Carpathian Basin, but the Dutch Beakers acquired their high level of Yamnaya-related ancestry from their Single Grave predecessors, who, in turn, acquired it from their proto-Corded Ware ancestors from the steppe.

Admittedly, I find the discussion about the origin of the Bell Beaker cultural package somewhat confusing. For all I know, it might have come from Iberia, the Carpathian Basin, or even North Africa. But this post isn't about that, it's about the homeland of the classic Beaker warrior male, with his R1b-P312, Corded Ware-like genome-wide genetic structure and brachycephalic skull. I'm almost certain now that this was the Lower Rhine region.

See also...

Hungarian Yamnaya > Bell Beakers?

Dutch Beakers: like no other Beakers

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

Friday, January 11, 2019

Hungarian Yamnaya > Bell Beakers?

Ever since the publication of the Olalde et al. Beaker paper (see here), there's been a lot of talk online about Hungarian Yamnaya as the most likely source of the Yamnaya-related, R1b-P312-rich northern Bell Beakers who went on to dominate much of Central and Western Europe during the Late Neolithic and Bronze Age.

Certainly, this is still possible, and we might find out soon if it's true because several Hungarian Yamnaya samples are apparently about to be published. But I wouldn't bet the proverbial farm on it just yet.

The most Yamnaya-like Beaker in the Olalde et al. dataset and ancient DNA record to date is from the Szigetszentmiklós burial site, which is indeed in present-day Hungary. But this individual, labeled I2787, is dated to just 2457–2201 calBCE, which isn't an early date for a Beaker and probably a couple hundred years past the proto-Beaker time frame.

Moreover, he belongs to Y-haplogroup R1b-Z2103, a paternal marker most closely associated in the ancient DNA record with eastern Yamnaya groups. And he doesn't exactly look like a classic northern Beaker, because he doesn't have a brachycephalic head with an exceedingly flat occiput (like this).

So I'd say that this is either an acculturated Beaker of recent Yamnaya origin, or perhaps the son of a Yamnaya father and Beaker mother. Below are several qpAdm mixture models that I ran to explore the latter possibility. They look very solid.

Beaker_Bavaria 0.442±0.045
Yamnaya_Samara 0.558±0.045

chisq 8.562
tail prob 0.73982
Full output

Beaker_Czech 0.441±0.045
Yamnaya_Samara 0.559±0.045

chisq 10.009
tail prob 0.61513
Full output

Beaker_The_Netherlands 0.576±0.062
Yamnaya_Samara 0.424±0.062

chisq 11.469
tail prob 0.489238
Full output

The idea that I2787 is a Beaker with recent Yamnaya ancestry isn't an original one. It was put forth very eloquently and convincingly months ago by the Bell Beaker Blogger himself:

Szigetszentmiklós Cemetery (Santa's Six Foot Elves)

I2786 is another Beaker male from the Szigetszentmiklós site who shows excess Yamnaya-related ancestry compared to most other Beakers. Again, it's likely that this individual harbors recent Yamnaya ancestry, because his Y-haplogroup is I2a-M223, which has been recorded in eastern Yamnaya alongside R1b-Z2103.

So my gut feeling for now is that Hungarian Yamnaya samples will mostly belong to Y-haplogroups R1b-Z2103 and I2a-M223, rather than R1b-P312, and thus they won't fit the bill in any obvious way as the population that may have given rise to northern Beakers.

One of the oldest individuals in the ancient DNA record belonging to R1b-P312 is I5748, a Beaker dated to 2579–2233 calBCE from the Oostwoud-Tuithoorn burial site in what is now West Frisia, The Netherlands.

Interestingly, this part of Northwestern Europe was home to the Single Grave population shortly before I5748 was alive. And the Single Grave culture is a variant of the Corded Ware culture. So can anyone tell me if there's any evidence that I5748 and his kind were relative newcomers to West Frisia, from, say, somewhere in the direction of the Carpathian Basin? If not, then what are the chances that northern Beakers are by and large the descendants of the Single Grave people?

In fact, there's not much difference in terms of genome-wide genetic structure between the Beakers from the Oostwoud-Tuithoorn site and Corded Ware people from what is now Germany. The Principal Component Analysis (PCA) below illustrates this well. But, you might say, Corded Ware males by and large belong to Y-haplogroup R1a-M417. Yep, but this doesn't mean that R1b-P312 wasn't common in some Single Grave clans.

At this stage, I don't have a clue where the northern Beakers might have come from, and unfortunately I don't have any inside information about the Y-haplogroups of Hungarian Yamnaya. I don't even know if any Single Grave samples are being analyzed. But I'll leave you with this map from a recent paper by French archeologist and Beaker expert Olivier Lemercier (see here). To me it suggests rather strongly that northern Beakers developed from the synthesis of Corded Ware newcomers to Western Europe and indigenous Western Europeans. As far as I can tell, that's what the paper basically argues as well.

See also...

Single Grave > Bell Beakers

Dutch Beakers: like no other Beakers

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

Monday, January 7, 2019

PIE Urheimat poll: two or three options left

If we let ancient DNA dictate the terms in the Proto-Indo-European (PIE) homeland debate ahead of historical linguistics and archeology, then, as far as I can see, there are two or three realistic options for the location of the said homeland. Here they are, in order of my own preference:

1) The Don-Caspian steppe around 4,300 BCE (see here). The ancestors of the Hittites and other Anatolian speakers also came from this homeland and entered Anatolia via the Balkans (or, less likely, the Caucasus) in fairly small groups sometime between 4,000 and 2,000 BCE. A lot of samples from Bronze Age Anatolia are needed to confirm or debunk the presence of steppe ancestry there.

2) The eastern Balkans during the peak of the ostentatious Copper Age in the region. Proto-Indo-European developed in the wealthy Chalcolithic communities of the western Black Sea coast and quickly spread both into the steppes and Anatolia via elite and trade contacts, and thus with minimal gene flow. Proto-Indo-European minus Anatolian, or PNIE, then spread from Eastern Europe during the Bronze Age with the mass migrations of the Yamnaya and closely related populations. A lot of samples from Chalcolithic western Anatolia are needed to confirm or debunk that people moved from the Balkans into Anatolia at this time.

3) Transcaucasia and/or nearby around 10,000 BCE. Proto-Indo-European, or rather Indo-Hittite, is much older than generally accepted, and came from the Epipaleolithic northern Near East. It was introduced into the steppes by foragers of the so called Caucasus Hunter-Gatherer (CHG) type, where it eventually became Proto-Indo-European minus Anatolian, or PNIE. Proto-Anatolian was spoken by closely related CHG-like foragers who stayed in the northern Near East.

Admittedly, that last theory is way out there, and at the moment, has about as much chance of being accepted by most historical linguists as Out-of-India. But the one advantage that is has over the other two proposals is that it doesn't need any additional sampling of ancient DNA.

I'll probably get grilled in the comments as to why I didn't include a proposal with the Maykop culture as the PIE community, or at least the Indo-Europeanizing agent in the steppe. Honestly, after seeing the ancient DNA from a wide range of Maykop remains courtesy of Wang et al., I think the chances that Maykop was an Indo-European-speaking culture are low. Indeed, both the Maykop genome-wide data and uniparental markers scream "Northwest Caucasian" to me.

Also, if the Caucasus was the PIE homeland, or even a major expansion point for early Indo-European languages, then considering its widely accepted status as a linguistic hotspot and refuge, it's fair to expect that it should still harbor at least one highly diverged Indo-European language. Is there any evidence that it ever did?

Below is an interactive poll. Please vote for one of the three options and feel free to let us know in the comments why you made the choice that you did. I might add more options to the poll if compelling reasons are given in the comments to do so.

PIE Urheimat poll
Don-Caspian steppe around 4,300 BCE
Chalcolithic eastern Balkans
Epipaleolithic northern Near East
Created with PollMaker
See also...

Yamnaya: home-grown

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

On the doorstep of India

Tuesday, January 1, 2019

The PIE homeland controversy: January 2019 status report

Last year, the preprint that claimed to have presented archaeogenetic data that opened up the possibility of the Proto-Indo-European (PIE) homeland being located south of the Caucasus was, ironically, also the preprint that considerably strengthened my confidence that the said homeland was actually located north of the Caucasus.

Of course, I'm talking about the Wang et al. manuscript at bioRxiv, which is apparently soon to be published as a peer-reviewed paper in Nature Communications (see here).

It'll be fascinating to observe if and how the peer-review process has impacted on the preprint, and especially its conclusion. My impression was that the authors seemed pretty sure that the Maykop people gave rise to the Yamnaya culture, or at least Indo-Europeanized it. But, as far as I saw, the archaeogenetic data didn't bear this out at all, and instead showed a lack of any direct, recent and meaningful genetic relationship between Maykop and Yamnaya (see here). Was this also picked up by the peer reviewers? We shall see.

Moreover, there was some exceedingly interesting fine print in the manuscript's supplementary information:

Complementary to the southern [Darkveti-Meshoko] Eneolithic component, a northern component started to expand between 4300 and 4100 calBCE manifested in low burial mounds with inhumations densely packed in bright red ochre. Burial sites of this type, like the investigated sites of Progress and Vonyuchka, are found in the Don-Caspian steppe [10], but they are related to a much larger supra-regional network linking elites of the steppe zone between the Balkans and the Caspian Sea [16]. These groups introduced the so-called kurgan, a specific type of burial monument, which soon spread across the entire steppe zone.

Always read the fine print, they say. And they're right. Imagine if I only read the preprint's conclusion and missed this little gem; I'd probably think that the PIE homeland was located south of the Caucasus rather than on the Don-Caspian steppe.

Wow, proto-kurgans with inhumations densely packed in bright red ochre? A supra-regional network linking the elites of the steppe all way from the Balkans to the Caspian Sea? An expansionist culture? And, as evidenced by the ancient DNA from the Progress and Vonyuchka sites, a people who may well have been in large part ancestral to the Yamnaya, Corded Ware and Andronovo populations, that have been identified based on archeological and historical linguistics data as the main vectors for the spread of Indo-European languages as far as Iberia in the west and the Indian subcontinent in the east.

I wonder if the authors actually asked themselves who these people may have been, before so haphazardly turning to Maykop and, ultimately, the Near East, as the likely sources of the Yamnaya culture? To me they look like the Proto-Indo-Europeans and true antecedents of Yamnaya.

So as things stand, my pick for the PIE homeland is firmly the Don-Caspian steppe. And I genuinely thank Wang et al., and indeed the Max-Planck-Institut für Menschheitsgeschichte (aka MPI-SHH), for their assistance.

But, you might ask, what about the Hittites? Yes, I realize that no one apart from me and a few of my readers here can find any steppe ancestry in the so called Hittite genomes published to date. However, consider this: if the PIE homeland really was on the steppe, and a dense sampling strategy of Hittite era Anatolia fails to turn up any unambiguous steppe ancestry in at least a few individuals, then there has to be an explanation for it. But let's wait and see what a dense sampling strategy of Hittite era Anatolia actually reveals before we go that far.

See also...

The PIE homeland controversy: August 2019 status report

Yamnaya: home-grown

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