The Hallstatt effect (?)

Just to see what would happen, I ran a subset of the highest coverage Bronze Age samples from what are now Britain and Ireland in my new Celtic vs Germanic Principal Component Analysis (PCA). Look for the Britain_&_Ireland_BA cluster. The relevant datasheet is available here.

Perhaps it's not a coincidence that the likely Celtic-speaking Iron Age individuals from present-day England (labeled England_IA) are positioned between these older British and Irish samples and the two ancients from Iron Age burials in present-day Bylany, Czechia, associated with the Hallstatt culture (marked with black stars). That's because the Hallstatt people are generally considered to have been the earliest speakers of Celtic languages.

Hence, what the PCA might be showing is a genetic shift in the British and Irish Isles caused by the arrival of Hallstatt Celts in Northwestern Europe.

Interestingly, the present-day English samples appear to be a mixture of Britain_&_Ireland_BA, England_IA and England_Anglo-Saxon. However, a subset of these samples is also heavily shifted "east" towards one of the Hallstatt individuals and present-day Dutch, suggesting that they harbor extra admixture from continental Europe.

This isn't easy to make out on my plot, because of the clutter, but I can assure you that it's true. Keep in mind that you can plug the datasheet into the PAST program (freely available here) to have a much closer look at the PCA and even change the color coding.

To check whether England_IA can be modeled as a mixture of Britain_&_Ireland_BA and Hallstatt with formal methods, I ran an analysis with the qpAdm software using all of the publicly available Bronze Age samples from present-day Britain and Ireland. The standard errors are high, likely because Britain_&_Ireland_BA and Hallstatt are closely related, but, overall, we can probably say that the model does limp across the line.

England_IA
Britain_&_Ireland_BA 0.555±0.172
Hallstatt 0.445±0.172
chisq 18.513
tail prob 0.100973
Full output

However, the really important thing about this output is that England_IA cannot be modeled as simply Britain_&_Ireland_BA (the chisq and tail prob are way off). Thus, even though the Hallstatt samples from Bylany don't appear to be ideal proxies for the admixture in England_IA that is lacking in Britain_&_Ireland_BA, the signal they produce does suggest that a closely related population arrived in the British Isles during or after the Bronze Age to give rise to England_IA.

See also...

Celtic probably not from the west

Celtic vs Germanic Europe

AmtDB: an interactive ancient human mitogenome database

A very useful resource called AmtDB has just come online. For background info, check out the relevant paper by Ehler et al. here. Below is the paper abstract:

Ancient mitochondrial DNA is used for tracing human past demographic events due to its population-level variability. The number of published ancient mitochondrial genomes has increased in recent years, alongside with the development of high-throughput sequencing and capture enrichment methods. Here, we present AmtDB, the first database of ancient human mitochondrial genomes. Release version contains 1107 hand-curated ancient samples, freely accessible for download, together with the individual descriptors, including geographic location, radiocarbon dating, and archaeological culture affiliation. The database also features an interactive map for sample location visualization. AmtDB is a key platform for ancient population genetic studies and is available at https://amtdb.org.

To give an example of how this thing works, I'll search for a very specific mitochondrial (mtDNA) haplogroup, H6a1b, which was recorded, perhaps unexpectedly, in a sample from Hittite era Anatolia (individual MA2208 from Damgaard et al. 2018). I say perhaps unexpectedly, because it's a marker that is today, by and large, restricted to Northern Europe. Here are the results...

Interestingly, H6a1b only pops up in Copper and Bronze Age individuals from what are now Czechia, Great Britain, Poland and Russia, with not a single instance from the Near East. Moreover, the oldest sample on the list is from an Yamnaya culture burial in Samara, Russia. Thus, if the presence of this marker in the Hittite sample isn't due to contamination or poor quality sequencing, then it's likely that some Hittites belonged to mtDNA haplogroups that arrived in Anatolia from the steppes of what is now Russia.

See also...

Focus on Hittite Anatolia

Dzudzuana Ice Age foragers: a different type of Caucasus hunter-gatherer (Lazaridis et al. 2018 preprint)

Over at bioRxiv at this LINK. Below is the abstract. Emphasis is mine.

The earliest ancient DNA data of modern humans from Europe dates to ~40 thousand years ago, but that from the Caucasus and the Near East to only ~14 thousand years ago, from populations who lived long after the Last Glacial Maximum (LGM) ~26.5-19 thousand years ago. To address this imbalance and to better understand the relationship of Europeans and Near Easterners, we report genome-wide data from two ~26 thousand year old individuals from Dzudzuana Cave in Georgia in the Caucasus from around the beginning of the LGM. Surprisingly, the Dzudzuana population was more closely related to early agriculturalists from western Anatolia ~8 thousand years ago than to the hunter-gatherers of the Caucasus from the same region of western Georgia of ~13-10 thousand years ago. Most of the Dzudzuana population's ancestry was deeply related to the post-glacial western European hunter-gatherers of the 'Villabruna cluster', but it also had ancestry from a lineage that had separated from the great majority of non-African populations before they separated from each other, proving that such 'Basal Eurasians' were present in West Eurasia twice as early as previously recorded. We document major population turnover in the Near East after the time of Dzudzuana, showing that the highly differentiated Holocene populations of the region were formed by 'Ancient North Eurasian' admixture into the Caucasus and Iran and North African admixture into the Natufians of the Levant. We finally show that the Dzudzuana population contributed the majority of the ancestry of post-Ice Age people in the Near East, North Africa, and even parts of Europe, thereby becoming the largest single contributor of ancestry of all present-day West Eurasians.

Lazaridis et al., Paleolithic DNA from the Caucasus reveals core of West Eurasian ancestry, bioRxiv, posted September 21, 2018, doi: https://doi.org/10.1101/423079

See also...

Villabruna cluster =/= Near Eastern migrants

Celtic vs Germanic Europe

I have a feeling that ancient DNA from post-Bronze Age Northwestern Europe will be coming thick and fast from now on. To get the most out of such data I've designed a new Principal Component Analysis (PCA) that does a better job of separating the Celtic- and Germanic-speaking populations of Europe than my previous efforts of this sort (see here and here). Below are two different versions of the same PCA. The relevant datasheet is available here.

And here's a Discrimination Analysis (LDA) plot based on the 25 principal components. It further differentiates many of the populations along the east > west cline of genetic diversity.

The difference between the Germanic Anglo-Saxons and the Celtic and Roman Britons of what is now eastern England is obvious. The Anglo-Saxons could pass for Scandinavians, while the Celts and Romans both cluster between the Irish and French. This makes good sense, and is exactly what I was looking for. It's also interesting to see the presumably Celtic-speaking Hallstatt samples from Bylany, Czechia, clustering with the Belgians.

Update 14/12/2019: Pictured below is a new version of my Celtic vs Germanic genetic map. It's based on the same Principal Component Analysis (PCA) as the original, but more focused on Northwestern Europe and produced with a different program.

To see the interactive online version, navigate to Vahaduo Custom PCA and copy paste the text from here into the empty space under the PCA DATA tab. Then press the PLOT PCA button under the PCA PLOT tab. For more guidance, refer to the screen caps here and here.

To include a wider range of populations in the key, just edit the data accordingly. For instance, to break up the ancient grouping into more specific populations, delete the Ancient: prefix in all of the relevant rows. This is what you should see:

Conversely, you can leave the ancient sample set intact and instead reorder the present-day linguistic groupings into, say, geographic groupings. To achieve this just delete all of the linguistic prefixes, such as Celtic:, Germanic:, and so on. You should end up with a datasheet like this and plot like this.

Of course, you can design your own plot by using any combination of the ancient and present-day individuals and populations that I've already run in this PCA. Their coordinates are listed here. Indeed, if you're in the possession of your own Celtic vs Germanic PCA coordinates, you can add yourself to the plot. And if you're not, see here.

It's also possible to re-process PCA data via the SOURCE tab. But I don't recommend doing this with the Celtic vs Germanic data, which are derived from a fine scale analysis and don't pack much variation. On the other hand, Global25 data are ideal for such re-processing. I made the plots below from subsets of Global25 coordinates available in a zip file here. To see how, refer to the screen caps here and here.

See also...

Modeling your ancestry has never been easier

Getting the most out of the Global25

Modeling genetic ancestry with Davidski: step by step

Avars and Longobards

Most of the "barbarians" from today's Amorim et al. paper have made it into the Global25 datasheets. Look for the samples with Collegno and Szolad in their labels. Same links as always...

Global25 datasheet ancient scaled

Global25 pop averages ancient scaled

Global25 datasheet ancient

Global25 pop averages ancient

Here's my usual Principal Component Analysis (PCA) of West Eurasian variation with the same individuals. As seen in the paper, the two females from Avar burials are very European indeed, with no hints of any recent Asian ancestry. The relevant datasheet is available here.

And this is my Global25-derived North European PCA featuring a subset of these samples that plotted firmly with present-day populations from north of the Alps, Balkans and Pyrenees. The aforementioned Avars (red dots) are sitting within the Polish cluster. The relevant datasheet is available here.

See also...

Greeks in a Longobard cemetery

First real foray into Migration Period Europe: the Gepid, Roman, Ostrogoth and others

Blast from the past: Yamnaya prediction from 2016

I wonder what's holding up the publication of the Wang et al. "Greater Caucasus" preprint? It was released back in May at the bioRxiv (see here). On a related note, I was looking back at some of the stuff that I wrote about the origin of the Yamnaya people (aka Steppe_EMBA), and found this...

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

The relevant blog post from 2016 is here. I totally forgot that I made such a bold prediction. But it actually has a very good chance now of being proven correct, more or less.

This, however, depends on the precise origin of the Yamnaya-like Eneolithic populations of the southernmost parts of the Pontic-Caspian steppe. But, considering the data in Wang et al., I think the possibility that they date back to the Pottery Neolithic period, and are thus indigenous to the region, looks quite high.

About a year later I made a prediction about the genetic structure of the Maykop people, and was basically proven right by Wang et al. (see here). Admittedly, my jaw dropped when I saw how the Steppe Maykop individuals came out in the preprint, with their Botai-like ancestry that is missing in all Yamnaya populations sampled to date. But it was an interesting outcome and nice to be surprised by ancient DNA yet again.

See also...

Genetic borders are usually linguistic borders too

Ahead of the pack

Open thread: What are the linguistic implications of Olalde et al. 2019?

Major horse paper coming soon

Horse domestication is an important and controversial topic, in large part because it's intimately tied to the debate over the location of the Proto-Indo-European (PIE) homeland. Based on the currently available genetic and archaeological data, it seems likely that all modern domesticated horse breeds ultimately derive from the Pontic-Caspian steppe in Eastern Europe (see here and here).

In the interview linked to below (click on the image) horse expert Alan Outram reveals that a new paper will be published within months that will test this theory, and either confirm or debunk it.

Outram also talks about the colonization of Central Asia during the Middle Bronze Age by groups from the west associated with the Sintashta culture. He says that this was probably an aggressive affair, akin to the more recent European colonization of North America, that may have pushed the Botai people, who were the indigenous inhabitants of the Kazakh steppe, and their horses far to the east. This, he suggests, might explain why the Przewalski horse of Mongolia appears to be derived from the Botai horse.

See also...

The mystery of the Sintashta people

Focus on Hittite Anatolia

Friendly Yeniseian steppe pastoralists