When did Celtic languages arrive in Britain?

A new paper at Nature by Patterson et al. argues that Celtic languages spread into Britain during the Bronze Age rather than the Iron Age [LINK]. This argument is based on the observation that there was a large-scale shift in deep ancestry proportions in Britain during the Bronze Age.

In particular, the ratio of Early European Farmer (EEF) ancestry increased significantly in what is now England during the Late Bronze Age (LBA). On the other hand, the English Iron Age was a much more stable period in this context.

I don't have any strong opinions about the spread of Celtic languages into Britain, and Patterson et al. might well be correct, but their argument is potentially flawed because:

- significant population shifts need not result in any noticeable changes in ancient ancestry proportions

- ancient ancestry proportions can shift without significant migrations from afar due to cryptic population substructures

- large-scale population shifts need not result in langage shifts, especially if they're gradual

- small-scale population shifts can result in language shifts, especially if they're sudden.

Indeed, when I plot some of the key ancient samples from the paper in my ultra fine scale Principal Component Analyses (PCA) of Northern and Western Europe, it appears that it's only the Early Iron Age (EIA) population from England that overlaps significantly with a roughly contemporaneous group from nearby Celtic-speaking continental Europe. The relevant PCA data are available here and here, respectively.

See also...

Celtic vs Germanic Europe

Avalon vs Valhalla revisited

R1a vs R1b in third millennium BCE central Europe

Looking forward to a post-Covid world

I was hoping that the Covid-19 pandemic wouldn't have an immediate impact on the publication of ancient DNA papers and new data, but considering how much things have slowed down in this respect, it seems that I was fooling myself.

So let's take a break until early next year, and then see what happens.

Trust me, we've got a lot to look forward to in the post-Covid-19 world. Based on what I've heard from various sources, here are some predictions about what we might see:

- the search for the Proto-Indo-European homeland will shift west to the North Pontic steppe

- on the other hand, the search for the Proto-Uralic homeland will move deep into Siberia

- the key role of the Single Grave (westernmost Corded Ware) culture in the population history of Western Europe will finally get some attention

- following on from the above, Y-haplogroup R1b-L51 will be revealed as a Single Grave marker

- the idea that the Pontic-Caspian steppe was colonized by migrants from Mesopotamia during the Bronze Age will be forgotten, and, ironically, we'll instead learn that there was a significant influx of steppe ancestry into ancient Mesopotamia

- Old Kingdom Egyptians will come out less Sub-Saharan African than present-day Egyptians.

I probably shouldn't blab everything out, so that's all you're getting from me for now. You'll just have to wait for the rest until next year, or perhaps even the year after that.

See also...

Is Yamnaya overrated?

Four years after the publication of the seminal ancient DNA paper Massive migration from the steppe is a source for Indo-European languages in Europe by Haak et al., we're still waiting for some of its loose ends to be finally tied up with new samples. In particular...

- if the men of the Corded Ware culture (CWC) were, by and large, derived from the population of the Yamnaya culture, then where are the Yamnaya samples with R1a-M417, the main CWC Y-haplogroup?

- if the men of the Bell Beaker culture (BBC) were also, by and large, derived from the population of the Yamnaya culture, then where are the Yamnaya samples with R1b-P312, the main BBC Y-haplogroup?

- and, most crucially, if R1b-L51, which includes R1b-P312, and is nowadays by far the most important Y-haplogroup in Western Europe, arrived there from the Pontic-Caspian steppe, then why hasn't it yet appeared in any of the ancient DNA from this part of Eastern Europe or surrounds, except of course in samples that are too young to be relevant?

I'm certainly not suggesting that, in hindsight, the said paper now looks fundamentally flawed. In fact, I'd say that it has aged remarkably well, especially considering how fast things are moving in the field of ancient genomics.

But those loose ends really need tying up, one way or another. It's now time.

So someone out there, please, let us know finally if you have the relevant Yamnaya samples. And if you don't, that's OK too, just tell us what you do have. Indeed, it'd be nice know a few basic details about the thousands of samples that have been successfully sequenced in various labs and are waiting to be published. A lot of people would appreciate it.

See also...

Corded Ware as an offshoot of Hungarian Yamnaya (Anthony 2017)

Hungarian Yamnaya > Bell Beakers?

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

A Bell Beaker superhighway

Below is a density heat map of Bell Beaker pottery finds from a recent paper titled Der Glockenbecher in Europa - eine Karteirung (The mapping of the Bell Beaker in Europe). It's freely available as part of a series of new archeological papers on the Bell Beaker phenomenon at the Journal of Neolithic Archeology (see here).

Particularly eye catching, at least for me, is the trail of high density clusters that runs from the Carpathian Basin to the North Sea, especially in the context of recent online discussions about the potential geographic origins of the non-Iberian, or Yamnaya-related, Beakers with significant steppe ancestry. I'm guessing that this was something of a Beaker superhighway back in the day.

By itself, the heat map is probably very favorable to the rather popular idea nowadays that the Yamnaya-related Beakers originated in the Carpathian Basin. Their ancestors, for instance, may have been Yamnaya groups that arrived from the Pontic-Caspian steppe via the Balkans, and their ethnogenesis may have been sparked by the cultural impulses that were streaming into the region from across Europe, perhaps from as far away as Iberia. The descendants of these early, potentially Yamnaya-derived, Beakers may then have moved en masse to the North Sea region and beyond via the aforementioned superhighway.

However, fortunately, we now also have quite a bit of ancient DNA data to throw into such debates. Note that I added the following labels to the map: Beaker The Netherlands, Beaker Mittelelbe-Saale, Beaker Bohemia, and Beaker Hungary. These are the currently sampled Beaker populations from along the so called superhighway, and you can see how they cluster compared to each other in my Principal Component Analysis (PCA) of ancient West Eurasian genetic variation.

Clearly, what we're dealing with here is not just a series of well settled sites, or a heavily populated trade route, but also a busy migration trail, because of the significant overlap in the PCA between almost all of the Beaker populations.

Interestingly, though, most of the gene flow appears to have gone from the northwest to the southeast, because the Dutch Beakers hardly overlap with the other groups, and arguably form the tightest cluster, suggesting that they're the most genetically homogeneous and unadmixed of these Beakers. Indeed, they're also genetically very similar to the earlier nearby Corded Ware groups from Germany and Scandinavia, so it's unlikely that they derive from recent migrants to Northern Europe. On the other hand, the Hungarian Beakers from the Carpathian Basin are by far the most dispersed of the lot, which certainly means that they're the least genetically homogeneous and probably the most admixed.

Note also that some of them do clearly "pull" towards the Dutch Beakers, suggesting that they might harbor significant ancestry from as far north as the shores of the North Sea.

See also...

The Boscombe Bowmen

Single Grave > Bell Beakers

Dutch Beakers: like no other Beakers

The Boscombe Bowmen

I'm thinking that the Boscombe Bowmen site in Wiltshire, southern England, might be a valuable case study of how the Bell Beaker population, and thus also the present-day western European gene pool, came to be.

Dated to 2500–2140 BCE, this isn't an especially early Bell Beaker grave, but its inventory is intriguing. It includes seven All-Over-Cord (AOC) beakers and one Cord-Zoned-Maritime (CZM) beaker.

Maritime beakers are quintessential Bell Beaker gear, and they're named as such because most of them have been recovered from sites along the Atlantic and Mediterranean coasts. However, strictly speaking, AOC beakers aren't Bell Beaker artifacts. Rather, their origin is said to be in the Single Grave culture, which is, of course, the northwestern European variant of the Corded Ware culture.

Genotype data for two samples from the Boscombe cemetery were analyzed in and published along with last year's Olalde et al. Beaker paper. In tune with the archeological data, one of these individuals came out very Corded Ware-like, with a lot of steppe ancestry, and the other rather southern, with among the lowest level of steppe ancestry for a Beaker dated to later than ~2500 BCE.

To take a closer look at their genetic affinities, I put together the graph below based on a couple of D-stats of the form D(Mbuti,X)(Yamnaya_Samara)/D(Mbuti,X)(Barcin_N,WHG). The bowmen are labeled I2416 and I2417, and the relevant datasheet is available here.

Considering these results, I2416 and I2417 may have been migrants, or the descendants of migrants, from such relatively far flung places as, say, what are now northern Germany and western France, respectively. [Edit: as per the comments below, these individuals are probably third-degree relatives, which makes it unlikely that they're migrants to the region, although it's still possible that their recent ancestors may have been migrants]

Note also that almost all of the populations are basically sitting between the two bowmen. This indeed suggests to me that the cultural processes and resulting population mixtures that took place at the Boscombe site also played out across the width and breadth of the Beaker realm, giving rise to heterogeneous Beaker groups almost everywhere within it and, eventually, the present-day western European gene pool.

Most of the Scandinavians, as well as the closely related British Anglo-Saxons, are slightly pulled above the red trend line by their excess genetic affinity to Western European Hunter-Gatherers (WHG). This phenomenon appears to date back to at least 2275-2032 BCE, because Nordic_LN:RISE98 is clearly affected by it and dated to this period.

My guess is that Single Grave populations from what is now Denmark and surrounds harbored much higher levels of WHG-related ancestry than the more easterly Corded Ware (aka Battle-Axe) Scandinavian groups, and they passed this onto present-day Scandinavians. Nordic_LN:RISE98, although from a burial site in what is now southern Sweden, might well be of Danish Single Grave origin.

See also...

Single Grave > Bell Beakers

Dutch Beakers: like no other Beakers

Hungarian Yamnaya > Bell Beakers?

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...

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...

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_Hungary_I2787
Beaker_Bavaria 0.442±0.045
Yamnaya_Samara 0.558±0.045
chisq 8.562
tail prob 0.73982
Full output

Beaker_Hungary_I2787
Beaker_Czech 0.441±0.045
Yamnaya_Samara 0.559±0.045
chisq 10.009
tail prob 0.61513
Full output

Beaker_Hungary_I2787
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...

Genetic substructures within the HapMap CEU sample (and Eurogenes' Northwest Europeans)

In this experiment I attempt to characterize more precisely the origins of some of the individuals from the HapMap CEU cohort. These samples are described by the HapMap project as Utah Americans of Western and Northern European descent. But this doesn't seem to be exactly true for at least two of them, who actually come out very Central European in all my tests. Moreover, it's obvious that some of the samples fit nicely into very specific areas of Western and Northern Europe. For instance, at this level of resolution, a few could pass as Irish, and others for Danes or even Swedes. Below is a quick and dirty ADMIXTURE analysis designed specifically for this experiment.

Key: Red = Sub-Saharan African, Yellow = Southern European, Green = North-Central European, Aqua = North Atlantic, Blue = Baltic, Pink = East Asian. See spreadsheet for details.


Based on the K=6 results it's fair to say that at least six of the CEU samples might pass for unmixed Scandinavians, most likely Danes or southern Swedes (NA12003, NA12057, NA12248, NA12249, NA12776 and NA12875). At least five could be confused for Irish or western British samples (NA10850, NA12005, NA12006, NA12386 and NA12812). The two Central European-like Utahns stick out from the CEU set due to their unusually high Baltic scores (NA11917 and NA12286). From the little I know about the CEU samples, I'd say that these two were of eastern or southeastern German origin. But they might have fairly recent ancestry from further east than that. My own MDS analysis (first image below) and a PCA plot from Lao et al. 2008 (second image, slightly edited by me to remove article text) confirm that such Scandinavian-like, German-like and Irish-like individuals do exist in the CEU set.

So the CEU set is not a homogeneous one, and carries clear substructures that can be picked up via fairly basic means. However, this doesn't make the CEU samples less valuable, but more so, due to the lack of public access to continental Northwestern European samples. Secondly, the test reveals some interesting information about the genetic substructures within Northwestern Europe. Here are some of my observations:

- Scandinavians often show very high levels of the North-Central European component, and moderately high levels of the North Atlantic component. Many also carry clear amounts of the Baltic component, but, as a rule, lower levels of the Southern European component.

- Germans mainly differ from the Scandinavians in that they carry the Southern European component at appreciable amounts. They show variable amounts of the Baltic component, with those from eastern Germany carrying the highest levels.

- Irish project members, especially those from western Ireland, show very high levels of the North Atlantic component, but low levels of the Southern European component.

- Western British samples, like those from Cornwall or western Scotland, are generally very similar to the Irish, mainly in that they carry the North Atlantic component at high levels. However, they often show somewhat higher levels of the Southern European component.

I'm eventually going to test these classifications of the CEU samples with ChromoPainter, which is by far the most accurate tool for such things at the moment. Unfortunately, it's also a lot of hard work and computationally intensive, so it might take a few weeks. I do have the allele frequencies from the above ADMIXTURE run, and it is possible to make a stand alone test from them. However, I'm not certain that's a good idea at present, due to the small number of samples involved. It might be worth doing when the right samples swell in number, so I can run a more robust analysis. In particular, I need more people from Ireland, Scotland and Scandinavia.

Reference...

Oscar Lao et al, Correlation between Genetic and Geographic Structure in Europe, Current Biology, Volume 18, Issue 16, 1241-1248, 26 August 2008, doi:10.1016/j.cub.2008.07.049