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Sunday, December 1, 2019

Big deal of 2019: ancient DNA confirms the link between Y-haplogroup N and Uralic expansions

The academic consensus is that Indo-European languages first spread into the Baltic region from the Eastern European steppes along with the Corded Ware culture (CWC) and its people during the Late Neolithic, well before the expansion of Uralic speakers into Fennoscandia and surrounds, probably from somewhere around the Ural Mountains.

On the other hand, the views that the Uralic language family is native to Northern Europe and/or closely associated with the CWC are fringe theories usually espoused by people not familiar with the topic or, unfortunately it has to be said, mentally unstable trolls.

The likely close relationship between the CWC expansion and the early spread of Indo-European languages was discussed in several papers in recent years (for instance, see here). This year, we saw the first ancient DNA paper focusing on the transition from the Bronze Age to the Iron Age in the East Baltic, including the likely first arrival of Uralic speech in what is now Estonia.

Published in Current Biology courtesy of Saag et al., the paper showed that the genetic structure of present-day East Baltic populations largely formed in the Iron Age (see here). It was during this time, the authors revealed, that the region experienced a sudden influx of Y-chromosome haplogroup N, which is today common in many Uralic speaking populations and often referred to as a Proto-Uralic marker. Little wonder then that Saag et al. linked this genetic shift in the East Baltic to the westward migrations of early Uralic speakers.

The table below, based on data from the Saag et al. paper, surely doesn't leave much to the imagination about what happened.

Unfortunately, I have to say that the genome-wide analysis in the paper was less informative than it could have been. The authors focused their attention on rather broad genetic components, and, as a result, missed an interesting fine scale distinction between their Bronze Age and Iron Age samples. The spatial maps below, based on my Global25 data for most of the ancients from Saag et al., show what I mean. The hotter the color the higher the genetic similarity between them and present-day West Eurasian populations.

Note that the Bronze Age (Baltic_EST_BA) samples are most similar to the Baltic-speaking, and thus also Indo-European-speaking, Latvians and Lithuanians, rather than the Uralic-speaking Estonians, even though they're from burial sites in Estonia. On the other hand, the Iron Age (Baltic_EST_IA) samples show strong similarity to a wider range of populations, including Estonians and many other Uralic-speaking groups.

See also...

It was always going to be this way

Fresh off the sledge

More on the association between Uralic expansions and Y-haplogroup N

Monday, November 25, 2019

Viking Age Iceland

I finally managed to get some of the Icelandic ancients from Ebenesersdóttir et al. 2018 into the Global25 datasheets (see here). Better late than never. Look for the"ISL_Viking_Age" prefix. Below is a screen cap of a Principal Component Analysis (PCA) with the new samples. It was done with an online Global25 PCA runner freely available here.

The individuals classified as unadmixed Gaels and Norse by Ebenesersdóttir et al. generally also look like it based on their Global25 coordinates.

The mixture models below, using all of the populations from the Global25 "modern pop averages scaled" datasheet, were run with an online tool freely available here. Note that the ADD DIST COL option is set to 1X. This is a useful feature for modeling the fine scale ancestry of samples that are derived from very similar populations.

See also...

They came, they saw, and they mixed

Commoner or elite?

Who were the people of the Nordic Bronze Age?

Sunday, November 10, 2019

Open analysis and discussion thread: Etruscans, Latins, Romans and others

I've just added coordinates for more than 100 ancient genomes from the recently published Antonio et al. ancient Rome paper to the Global25 datasheets. Look for the population and individual codes listed here. Same links as always:

Global25 datasheet ancient scaled

Global25 pop averages ancient scaled

Global25 datasheet ancient

Global25 pop averages ancient

Thus far I've only managed to check a handful of the coordinates, so please let me know if you spot any issues. Below is a Principal Component Analysis (PCA) featuring the Etruscan and Italic speakers. I ran the PCA with an online tool specifically designed for Global25 coordinates freely available here.

Can we say anything useful about the origins of the Etruscan and early Italic populations thanks to these new genomes? Also, to reiterate my question from the last blog post, what are the genetic differences exactly between the Etruscans, early Latins, Romans and present-day Italians? Feel free to let me know in the comments below.

Update 13/11/2019: Here's another, similar PCA. This one, however, is based on genotype data, and it also highlights many more of the samples from the Antonio et al. paper. Considering these results, I'm tempted to say that the present-day Italian gene pool largely formed in the Iron Age, and that it was only augmented by population movements during later periods. The relevant datasheet is available here.

Update 13/11/2019: It seems to me that the two Latini-associated outliers show significant ancestry from the Levant, which possibly means that they're in part of Phoenician origin. These qpAdm models speak for themselves:

ITA_Proto-Villanovan 0.547±0.081
Levant_ISR_Ashkelon_IA2 0.453±0.081
chisq 7.573
tail prob 0.87027
Full output

ITA_Proto-Villanovan 0.679±0.068
Levant_ISR_Ashkelon_IA2 0.321±0.068
chisq 7.222
tail prob 0.89033
Full output

The Proto-Villanovan singleton is also a key part of the models. Dating to the Bronze Age/Iron Age transition, she appears to be of western Balkan origin. Moreover, her steppe ancestry is probably derived directly from the Yamnaya horizon.

HRV_Vucedol 0.677±0.031
Yamnaya_RUS_Samara 0.323±0.031
chisq 10.397
tail prob 0.661174
Full output

The cluster made up of four early Italic speakers can be modeled with minor Proto-Villanovan-related ancestry, but, perhaps crucially, it doesn't need to be. Indeed, judging by the qpAdm output below, it's possible that almost all of its steppe ancestry came from the Bell Beaker complex, and, thus, the Corded Ware culture complex before that.

Bell_Beaker_Mittelelbe-Saale 0.480±0.055
ITA_Grotta_Continenza_CA 0.411±0.042
ITA_Proto-Villanovan 0.109±0.084
chisq 10.294
tail prob 0.590205
Full output

Two out of the three available Etruscans look very similar to the Italic speakers in the above PCA plots, and yet they show a lot more Proto-Villanovan-related ancestry in my qpAdm run. The statistical fit is also relatively poor, perhaps suggesting that something important is missing.

Bell_Beaker_Mittelelbe-Saale 0.186±0.081
ITA_Grotta_Continenza_CA 0.283±0.064
ITA_Proto-Villanovan 0.531±0.126
chisq 17.175
tail prob 0.143143
Full output

Interestingly, the Etruscan outlier with significant North African admixture (proxied in my run by MAR_LN) doesn't need to be modeled with any Bell Beaker ancestry.

ITA_Proto-Villanovan 0.675±0.057
MAR_LN 0.325±0.057
chisq 14.864
tail prob 0.315912
Full output

Update 17/11/2019: The spatial maps below show how three groups of ancient Romans (from the Imperial, Late Antiquity and Medieval periods) compare to present-day West Eurasian populations in terms of their Global25 coordinates. The hotter the color, the higher the similarity. More here.

See also...

Getting the most out of the Global25

Thursday, November 7, 2019

What's the difference between ancient Romans and present-day Italians?

The first paper on the genomics of ancient Romans was finally published today at Science [LINK]. It's behind a paywall, but the supplementary info is freely available here. Below is a quick summary of the results courtesy of the accompanying Ancient Rome Data Explorer.

I'm told that the genotype data from the paper will be online within a day or so at the Pritchard Lab website here. I'll have a lot more to say about ancient Romans and present-day Italians after I get my hands on it.

See also...

Open analysis and discussion thread: Etruscans, Latins, Romans and others

Tuesday, November 5, 2019

Modeling your ancestry has never been easier

An exceedingly simple, yet feature-packed, online tool ideal for modeling ancestry with Global25 coordinates is freely available HERE. It works offline too, after downloading the web page onto your computer. Just copy paste the coordinates of your choice under the "source" and "target" tabs, and then mess around with the buttons to see what happens. The screen caps below show me doing just that.

Another free, easy to use online tool that works with Global25 coordinates is the Principal Component Analysis (PCA) runner HERE. Below is a screen cap of me checking out one of the eleven PCA that it offers.

See also...

Getting the most out of the Global25

Wednesday, October 16, 2019

The Battle Axe people came from the steppe (Malmstrom et al. 2019)

It's been obvious for a while now that the Corded Ware culture (CWC) and its Scandinavian variant, the Battle Axe culture (BAC), originated on the Pontic-Caspian steppe. However, Malmstrom et al. drive the point home in a new open access paper at Proceedings B [LINK]. From the paper, emphasis is mine:

The Neolithic period is characterized by major cultural transformations and human migrations, with lasting effects across Europe. To understand the population dynamics in Neolithic Scandinavia and the Baltic Sea area, we investigate the genomes of individuals associated with the Battle Axe Culture (BAC), a Middle Neolithic complex in Scandinavia resembling the continental Corded Ware Culture (CWC). We sequenced 11 individuals (dated to 3330–1665 calibrated before common era (cal BCE)) from modern-day Sweden, Estonia, and Poland to 0.26–3.24× coverage. Three of the individuals were from CWC contexts and two from the central-Swedish BAC burial ‘Bergsgraven’. By analysing these genomes together with the previously published data, we show that the BAC represents a group different from other Neolithic populations in Scandinavia, revealing stratification among cultural groups. Similar to continental CWC, the BAC-associated individuals display ancestry from the Pontic–Caspian steppe herders, as well as smaller components originating from hunter–gatherers and Early Neolithic farmers. Thus, the steppe ancestry seen in these Scandinavian BAC individuals can be explained only by migration into Scandinavia. Furthermore, we highlight the reuse of megalithic tombs of the earlier Funnel Beaker Culture (FBC) by people related to BAC. The BAC groups likely mixed with resident middle Neolithic farmers (e.g. FBC) without substantial contributions from Neolithic foragers.

By contrast, the CWC individuals from Obłaczkowo in Poland (poz44 and poz81) show an extremely high proportion of steppe ancestry (greater than 90%), which is different from the later CWC-associated individuals excavated in Pikutkowo (Poland) [23], but similar to some other CWC-associated individuals from Germany, Lithuania, and Latvia [2,8,31]. Interestingly, these individuals with a large fraction of steppe ancestry have typically been dated to more than 2600 BCE, making them among the earliest CWC individuals genetically investigated. This observation, i.e. early CWC individuals resembled (genetically) Yamnaya-associated individuals, while later CWC groups show higher levels of European Neolithic farmer ancestry (Pearson's correlation coefficient: −0.51, p = 0.006) (figure 2), suggests an initial dispersal that occurred rapidly.

See also...

Saturday, October 12, 2019

The Balkan connection

The hot topic at the moment is social inequality in Bronze Age Europe, thanks to a new paper by Mittnik et al. at Science. The full article is sitting behind an exceedingly robust paywall here.

However, the genotype dataset from the paper is freely available at the Max Planck Society's Edmond data repository here. Below is my Principal Component Analysis (PCA) of ancient West Eurasian genetic variation featuring 41 of the highest quality ancients from the new dataset. Almost all of them are from the Lech Valley in the Bavarian Alps, covering the period from the Bell Beaker culture (BBC) to the Middle Bronze Age (MBA). Two of the samples are from a mass Corded Ware culture (CWC) burial in the more northerly Tauber Valley.

I've also highlighted other ancients on the plot associated with the BBC and CWC from present-day Netherlands and Germany, respectively. The relevant PCA datasheet can be downloaded here.

Social stratification in ancient Europe is a fascinating topic, and it's an issue that I've started looking at myself (see here). However, I can't see any correlation between the inferred social standing of the individuals from the Lech and Tauber valleys and their positions in my PCA.

Nevertheless, the PCA is interesting in that it highlights considerable genetic heterogeneity within the Lech Valley BBC population. Indeed, how is this heterogeneity even possible, if, as per Mittnik et al., ancient DNA "has shown that the spread of the BBC throughout continental Europe did not involve large-scale migrations"?

Below is another version of my PCA, but this time focusing on three males: Lech Valley Beakers UNTA58_68Sk1 and WEHR_1192SkA, as well as ALT_4 from the aforementioned mass CWC grave in the Tauber Valley. Note that UNTA58_68Sk1 and WEHR_1192SkA represent genetically the most southern and northern, respectively, Lech Valley BBC samples that had enough data to be run in my analysis. I chose to focus on males because they carry the Y-chromosome, which can be informative about male-mediated ancient population expansions.

The PCA outcomes for these individuals are generally in line with their results in other types of genetic analyses, including those based on formal statistics. For instance, compared to the other two, ALT_4 harbors excess early steppe herder ancestry, UNTA58_68Sk1 excess early European farmer ancestry, and WEHR_1192SkA excess European hunter-gatherer ancestry. Moreover...

- UNTA58_68Sk1 shows a non-local isotopic signature and belongs to Y-haplogroup G2a, a marker essentially missing from BBC populations north of the Alps, and is best modeled as a two-way mixture between Bronze Age populations from the Balkans and the Pontic-Caspian steppe (see here), which probably means that he was a migrant to the Lech Valley from south of the Alps

- importantly, UNTA58_68Sk1 is not an isolated case, at least in the sense that several other BBC individuals from Bavaria, Bohemia, Hungary and Poland show varying ratios of Balkan-related ancestry, although almost all of these people are women

- WEHR_1192SkA is very similar to Bell Beakers from the northern Netherlands with whom he shares the R1b-P312 Y-haplogroup, suggesting that he was part of a population that moved into the Lech Valley from potentially as far away as the North Sea coast

- although ALT_4 probably shares the R1b-L51 Y-haplogroup with WEHR_1192SkA and many other BBC and Bronze Age individuals from the Bavarian Alps and surrounds, this can't be used as evidence of significant local genetic continuity after the CWC period, especially considering the comparatively eastern genome-wide structure of ALT_4.

Of course, archeological data suggest that the BBC was influenced in some important ways by the Copper and Bronze Age cultures of the Balkans and Carpathian Basin. So much so, in fact, that Marija Gimbutas, author of The Civilization of the Goddess, believed that the BBC originated in the Balkans from a synthesis of the local Vucedol culture and the intrusive Yamnaya culture from the Pontic-Caspian steppe.

Considering the ancient DNA evidence, however, the main demographic center of the early BBC could not have been south of the Alps.

Rather, it appears that early BBC and even CWC groups from north of the Alps moved into the Balkans and Carpathian Basin, where they may have established contacts with the local elites. If so, this might explain the significant southern cultural influences on the BBC, but limited accompanying genetic impact. This scenario also has support from archeological data (for instance, see here).

See also...

Is Yamnaya overrated?

The Boscombe Bowmen

Single Grave > Bell Beakers

Thursday, September 26, 2019

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...