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

Fresh off the sledge

As things stand, the closest individual to a Proto-Uralic speaker in the ancient DNA record is arguably 0LS10 from an Iron Age tarand grave in what is now Estonia. I say that because:

- isotopic data suggest that 0LS10 wasn't born where he died, and considering his elevated Siberian ancestry relative to earlier and most contemporaneous Baltic ancients, he was very likely a migrant to the Baltic region from the east

- the tarand grave tradition appears to be specifically a Finnic (west Uralic) phenomenon that probably spread from the Volga-Oka region, which is just west of where most people place the Proto-Uralic homeland

- 0LS10 belongs to Y-chromosome haplogroup N-L1026, a paternal marker that is especially closely associated with Uralic-speaking populations and probably only appeared in the East Baltic region during the transition from the Bronze Age to the Iron Age

You can find more background info about 0LS10 and other relevant samples in Saag et al. 2019 (see here). This is where he sits in my Principal Component Analyses (PCA) focusing on fine scale Northern European genetic diversity. The relevant datasheets are available here and here, respectively.

Note that 0LS10 doesn't cluster strongly with any ancient or modern populations. To investigate this in more detail I ran a series of two-way qpAdm analyses, testing tens of ancient individuals and populations as potential admixture sources. These two models stood out above the rest in terms of their statistical fits, chronology and overall plausibility.

Baltic_EST_IA_0LS10
Baltic_EST_BA 0.826±0.045
RUS_Sintashta_MLBA_o1 0.174±0.045
chisq 12.527
tail prob 0.564048
Full output

Baltic_EST_IA_0LS10
Baltic_EST_BA 0.683±0.102
RUS_Mezhovskaya 0.317±0.102
chisq 13.811
tail prob 0.463864
Full output

Please note that RUS_Sintashta_MLBA_o1 isn't representative of the Sintashta culture population as a whole. It's a group of the most extreme genetic outliers among the Sintashta samples, and they may or may not have been Uralic speakers (see here). Interestingly, the Mezhovskaya culture population is generally associated with the Ugric branch of the Uralic language family.

I was also able to closely replicate these results with the Global25/nMonte method; down to almost one per cent. However, the statistical fits (distances) are poor, probably because the reference populations aren't the real mixture sources. This is in line with the fact that their Y-haplogroups are Q1a, R1a and R1b, rather than any type of N.

Baltic_EST_IA:0LS10
Baltic_EST_BA,83.8
RUS_Sintashta_MLBA_o1,16.2
distance%=4.7955

Baltic_EST_IA:0LS10
Baltic_EST_BA,69.8
RUS_Mezhovskaya,30.2
distance%=3.5783

I do realize that two Bronze Age samples from Bolshoy Oleni Ostrov, Kola Peninsula, belong to N-L1026, but adding them to my mixture models doesn't help. Little wonder, because the Kola Peninsula lies within the Arctic Circle, and I'm pretty sure that 0LS10 and his N-L1026 came from somewhere just north of the mixture cline marked on the map below. Unfortunately, I can't test this directly yet due to the scarcity of ancient samples from this region.

See also...

It was always going to be this way

On the association between Uralic expansions and Y-haplogroup N

Uralic-specific genome-wide ancestry did make a signifcant impact in the East Baltic

Uralic-specific genome-wide ancestry did make a signifcant impact in the East Baltic

I've started analyzing the ancient genotype data from the recent Saag et al. paper on the expansion of Uralic languages and associated spread of Siberian ancestry into the East Baltic region. The paper is freely available here and the data are here.

I really like the paper, but I don't agree with the authors' claim that the appearance of Y-chromosome haplogroup N in what is now Estonia and surrounds during the Iron Age is "not matched by a clear shift in autosomal profiles". In my opinion it certainly is, and, as one would expect, it's a shift towards a genetic profile typical of western Uralic speakers.

I'd say that the easiest way to find this signal is with a Principal Component Analysis (PCA) focusing on fine scale genetic substructures within Northern Europe, like the one below. The relevant datasheet is available here.

Note that the East Baltic Iron Age samples, all from burial sites in what is now Estonia, appear to be peeling away from their Bronze Age predecessors and overlapping strongly with present-day Estonians, who are Uralic speakers. Indeed, the PCA suggests to me that the formation of the greater part of the present-day Estonian gene pool took place in the East Baltic during the transition from the Bronze Age to the Iron Age. That is, when Uralic languages are generally accepted to have arrived in the region from near the Ural Mountains in the east.

I was also able to closely replicate these outcomes with my Global25 data using the method described here. However, in this effort, present-day Estonians are clearly more western than the Estonian Iron Age samples (EST_IA), which might be due to the presence of low level Germanic ancestry in Estonia dating to the medieval period. The relevant datasheet is available here.

Interestingly, the Estonian Bronze Age samples (EST_BA) come from stone-cist graves which are widely hypothesized to have been introduced to the East Baltic from the Nordic Bronze Age civilization. I even recall reading a paper on the topic which claimed that the remains buried in such graves were those of Proto-Germanic-speaking Scandinavian migrants. Well, I haven't had a chance to study these samples in any great detail yet, but considering that in both of the PCA above they're overlapping strongly with Latvian Bronze Age samples (LVA_BA) and sitting far away from the nearest Scandinavians, I'd say they're probably of local stock from way back.

See also...

It was always going to be this way

On the association between Uralic expansions and Y-haplogroup N

Inferring the linguistic affinity of long dead and non-literate peoples: a multidisciplinary approach

It was always going to be this way

The native peoples of the East Baltic - Estonians, Latvians and Lithuanians - are genetically alike and their paternal gene pools are dominated by the same two Y-chromosome haplogroups: R1a and N3a.

Linguistically, however, Estonians are a world apart from Latvians and Lithuanians. That's because the Estonian language belongs to the Uralic language family, which has an obvious North Eurasian character. On the other hand, Latvian and Lithuanian are both classified as Indo-European languages, along with the vast majority of other European languages.

The Uralic and Indo-European language families may or may not descend from the same ancestral tongue, but even if they do, their relationship is very distant.

So how is it that Estonians came to speak a Uralic language? As far back as I can remember, the basic explanation accepted by most people was that Uralic speech arrived in what is now Estonia and neighboring Finland during the Bronze Age with migrants, or perhaps invaders, rich in N3a from somewhere around the Ural Mountains. Conversely, Latvians and Lithuanians were generally assumed to have retained the Indo-European speech of their R1a-rich forefathers from the Pontic-Caspian steppe, who colonized much of Eastern Europe north of the steppe during the Late Neolithic.

Ancient DNA has now uncannily corroborated these theories (for instance, see Mittnik et al. 2018 and, published today, Saag et al. 2019). All it took was a handful of samples from a few relevant sites. I think that's awesome; I love it when sensible, long-standing hypotheses are validated by cutting edge science.

I'll have a lot more to say about the spread of Uralic languages and Uralian genes to the East Baltic when I get my hands on the genotype data from the new Saag et al. paper. I also have a post coming soon about the Nordic Bronze Age. Stay tuned.

Update 10/05/2019: Uralic-specific genome-wide ancestry did make a signifcant impact in the East Baltic

See also...

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

Corded Ware people =/= Proto-Uralics (Tambets et al. 2018)

Inferring the linguistic affinity of long dead and non-literate peoples: a multidisciplinary approach