Baltic Finns in the Bronze Age, of hg. R1a-Z283 and Corded Ware ancestry

estonian-bronze-age-dna

Open access The Arrival of Siberian Ancestry Connecting the Eastern Baltic to Uralic Speakers further East, by Saag et al. Current Biology (2019).

Interesting excerpts:

In this study, we present new genomic data from Estonian Late Bronze Age stone-cist graves (1200–400 BC) (EstBA) and Pre-Roman Iron Age tarand cemeteries (800/500 BC–50 AD) (EstIA). The cultural background of stone-cist graves indicates strong connections both to the west and the east [20, 21]. The Iron Age (IA) tarands have been proposed to mirror “houses of the dead” found among Uralic peoples of the Volga-Kama region [22].

(…) The 33 individuals included 15 from EstBA, 6 from EstIA, 5 from Pre-Roman to Roman Iron Age Ingria (500 BC–450 AD) (IngIA), and 7 from Middle Age Estonia (1200–1600 AD) (EstMA) and yielded endogenous DNA ∼4%–88%, average genomic coverages ∼0.017–0.734×, and contamination estimates <4% (Table S1). We analyzed the data in the context of modern and other ancient individuals, including from Neolithic Estonia [13].

estonian-y-dna-bronze-iron-age
Archaeological Information, Genetic Sex, mtDNA and Y Chromosome Haplogroups, and Average Coverage of the Individuals of This Study. Modified from the paper to mark distinct Y-DNA haplogroups in the LBA and IA.

We identified chrY hgs for 30 male individuals (Tables 1 and S2; STAR Methods). All 16 successfully haplogrouped EstBA males belonged to hg R1a, showing no change from the CWC period, when this was also the only chrY lineage detected in the Eastern Baltic [11, 13, 30, 31]. Three EstIA and two IngIA individuals also belonged to hg R1a, but three EstIA males belonged to hg N3a, the earliest so far observed in the Eastern Baltic. Three EstMA individuals belonged to hg N3a, two to hg R1a, and one to hg J2b. ChrY lineages found in the Baltic Sea region before the CWC belong to hgs I, R1b, R1a5, and Q [10, 11, 12, 13, 17, 32]. Thus, it appears that these lineages were substantially replaced in the Eastern Baltic by hg R1a [10, 11, 12, 13], most likely through steppe migrations from the east [30, 31]. (…) Our results enable us to conclude that, although the expansion time for R1a1 and N3a3′5 in Eastern Europe is similar [25], hg N3a likely reached Estonia or at least became comparably frequent to modern Estonia [1] only during the BA-IA transition.

A clear shift toward West Eurasian hunter-gatherers is visible between European LN and BA (including Baltic CWC) and EstBA individuals, the latter clustering together with Latvian and Lithuanian BA individuals [11]. EstIA, IngIA, and EstMA individuals project between BA individuals and modern Estonians, partially overlapping with both.

(…) EstBA individuals are clearly distinguishable from Estonian CWC individuals as the former have more of the blue component most frequent in WHGs and less of the brown and yellow components maximized in Caucasus hunter-gatherers and modern Khanty, respectively. The individuals of EstBA, EstIA, IngIA, EstMA, and modern Estonia are quite similar to each other on average, indicating that the relatively high proportion of WHG ancestry in modern Eastern Baltic populations compared to other present-day Europeans [15] traces back to the BA.

estonian-pca-published
Detail of the PCA, modified from the paper to label populations. Estonian Bronze Age and Iron Age samples cluster close to Early Corded Ware from the Baltic.. Principal-component analysis results of modern West Eurasians with ancient individuals projected onto the first two components (PC1 and PC2). BA, Bronze Age; EF, early farmers; HG, hunter-gatherers; IA, Iron Age; IMA, Iron/Middle Ages; LN, Late Neolithic; LNBA, Late Neolithic/Bronze Age; MA, Middle Ages

When comparing Estonian CWC and EstBA using autosomal outgroup f3 and Patterson’s D statistics (Table S3), the latter is more similar to other Baltic BA populations, to Baltic IA and Middle Age (MA) populations, and also to populations similar to WHGs and Scandinavian hunter-gatherers (SHGs), but not to Estonian CCC (Figures 2A and S2A; Data S1). The increase in WHG or SHG ancestry could be connected to western influences seen in material culture [20, 21] and facilitated by a decline in local population after the CCC-CWC period [20]. A slight trend of bigger similarity of Estonian CWC to forest or steppe zone populations and of EstBA to European early farmer populations can also be seen.

(…) When comparing to modern populations, Estonian CWC is slightly more similar to Caucasus individuals but EstBA to Baltic populations and Finnic speakers (Figure 2B; Data S1). Outgroup f3 and D statistics do not reveal apparent differences when comparing EstBA to EstIA, EstIA to IngIA, and EstIA to EstMA (Data S1).

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qpAdm results. Error bars indicate one SE. Central MN, Central European Middle Neolithic; EstBA, Estonian Bronze Age; EstIA, Estonian Iron Age; IngIA, Ingrian Iron Age; EstMA, Estonian Middle Ages; WHG, western hunter-gatherers.

These results highlight how uniparental and autosomal data can lead to different demographic inferences—the genetic change between CWC and BA not seen in uniparental lineages is clear in autosomal data and the appearance of chrY hg N in the IA is not matched by a clear shift in autosomal profiles.

EstBA individuals have no Nganasan-related ancestry and EstIA, IngIA, and EstMA individuals on average have 2% or 4% (Figure 3; Data S1). The differentiation remains when using BA or IA Fennoscandian populations [26] instead of Nganasans (Data S1). Notably, the proportion of Nganasan-related ancestry varies between 0% and 12% among sampled EstIA, IngIA, and EstMA individuals (Data S1), which may suggest its relatively recent admixture into the target population. Moreover, two individuals from Kunda (0LS10 and V10) have the highest proportions of Nganasan ancestry among EstIA (6% and 8%), one of them has chrY hg N3a, and isotopic analysis suggests neither individual being born in Kunda [34].

About these two males from Tarand-graves, ‘foreign’ to Kunda:

0LS10: Male from tarand III (burial 9; TÜ 1325: L777), age 17–25 years [34]. He had a fragment of a sheep/goat bone and ceramics as grave goods. This burial has two radiocarbon dates: 2430 ± 35 BP (Poz-10801; 760–400 cal BC) and 2530 ± 41 BP (UBA-26114; 800–530 cal BC) [34]. According to the isotopic analysis, the person was not born in the vicinity of Kunda; his place of birth is still unknown (but south-western Finland and Sweden are excluded) [34]. Sampled tooth r P1.

V10: Male from tarand XI (burial 24; TÜ 1325: L1925), age 25–35 years [34], date 2484 ± 40 BP (UBA-26115; 790–430 cal BC) [34]. He had a few potsherds near the skull. Likewise, this person was not locally born [34]. Sampled tooth l P1.

estonia-bronze-iron-age-steppe-siberian
Autosomal Analyses’ Results for Gyvakarai1 as the closest available Corded Ware source for Balto-Finnic populations.

The paper shows thus:

  • Major continuity of ancestry from Corded Ware to modern Estonians, with only slight changes in different periods. In fact, one of the best fits for the Late Bronze Age ancestry is Gyvakarai1, one of the Corded Ware “outliers” described as “closer to Yamna”, which I already said may be closer to Sredni Stog/EHG populations instead. Another interesting take is that the change from Bronze Age to Iron Age corresponds to an increase in Baltic Corded Ware-related ancestry, rather than being driven by Siberian ancestry.
  • pca-mittnik-gyvakarai
    File modified by me from Mittnik et al. (2018) to include the approximate position of the most common ancestral components, and an identification of potential outliers. Zoomed-in version of the European Late Neolithic and Bronze Age samples. “Principal components analysis of 1012 present-day West Eurasians (grey points, modern Baltic populations in dark grey) with 294 projected published ancient and 38 ancient North European samples introduced in this study (marked with a red outline). From Mittnik et al. (2018).
  • A Volosovo-related migration of hg. N1c with Netted Ware into the area seems to be discarded, based on the full replacement of paternal lines and continuity of R1a-Z283. It is only during the Tarand-grave period when a system of chiefdoms (spread from Ananyino/Akozino) brings haplogroup N1c to the Gulf of Finland. During the Iron Age, the proportion of paternal lineages is still clearly in favour of R1a (50% in the coast, 100% in Ostrobothnia), which indicates a gradual replacement led by elites, likely because of the incorporation of Akozino warrior-traders spreading all over the Baltic, bringing the described shared Mordvinic traits in Fennic.
  • finno-ugric-haplogroup-n
    Map of archaeological cultures in north-eastern Europe ca. 8th-3rd centuries BC. [The Mid-Volga Akozino group not depicted] Shaded area represents the Ananino cultural-historical society. Fading purple arrows represent likely stepped movements of subclades of haplogroup N for centuries (e.g. Siberian → Ananino → Akozino → Fennoscandia [N-VL29]; Circum-Arctic → forest-steppe [N1, N2]; etc.). Blue arrows represent eventual expansions of Uralic peoples to the north. Modified image from Vasilyev (2002).
  • The arrival of Akozino warrior-traders (bringing N1c and R1a lineages) was probably linked to this minimal “Nganasan-like” ancestry of some samples in the transition to the Iron Age. This arrival is supported by samples 0LS10 (the earliest hg. N1c) and V10 (of hg. R1a), both dated to ca. 800-400 BC, with V10 showing the highest “Nganasan-like” ancestry with 4.8%, both of them neighbouring samples showing 0%. This variable admixture among local and foreign paternal lineages might support the described social system of family alliances with intermarriages. In fact, a medieval sample, 0LS03_1 (hg. R1a) also shows a recent “Nganasan-like” ancestry, which probably points to the integration of different Arctic-related ancestry components among Modern Estonians, in this case related to Finnish expansions and thus integration of Levänluhta-related ancestry, as per the supplementary data.
  • NOTE. Such minimal proportions of “Nganasan-like” ancestry evidence the process of admixture of Volga Finns in Akozino territory through their close interactions with Permians of Ananyino, who in turn acquired this Palaeo-Arctic admixture most likely during the expansion of the linguistic community to hunter-gatherer territories, to the north of the Cis-Urals. This process of stepped infiltration and expansion without language change is not dissimilar to the one seen among Indo-Iranians and Balto-Slavs of hg. R1b, or Vasconic speakers of hg. I2a, although in the case of Baltic Finns of hg. R1a the process of infiltration and expansion of hg. N1c is much less dramatic, with no radical replacement anywhere before the huge bottlenecks observable in Finns.

  • The expansion of haplogroup N1c among Finnic populations, as we are going to see in samples from the Middle Ages such as Luistari, is the consequence of late founder effects after huge bottlenecks expected based on the analysis of modern populations. The expansion of N1c-VL29 is different in origin from that of N1c-Z1936 among Samic (later integrated into Finnish populations), most likely from the east and originally associated with Lovozero Ware.
haplogroup_n3a3
Frequency-Distribution Maps of Individual Subclade N3a3 / N1a1a1a1a1a-CTS2929/VL29, probably initially with Akozino warrior-traders. Map from Ilumäe et al. (2016).

In spite of all this, the conclusion of the paper is (surprise!) that Siberian ancestry and hg. N heralded the arrival of Finnic to the Gulf of Finland in the Iron Age… However, this conclusion is supposedly* supported, not by their previous papers, but by a recent phylogenetic study by Honkola et al. (2013), which doesn’t actually argue for such a late ‘arrival’: it argues for the split of Balto-Finnic around 1500 BC.

NOTE. I say ‘supposedly’ because Kristiina Tambets, for example, has been following the link of Uralic with haplogroup N since the 2000s, so this is not some conclusion they just happened to misread from some random paper they Googled. In those initial assessments, she argued that the “ancient homeland” of the Tat C mutation suggested that Finno-Ugrians were in Fennoscandia before Indo-Europeans. Apparently, since haplogroup N appears later and from the east, it is now more important to follow this haplogroup than what is established in archaeology and linguistics.

Even in the referred paper, this split is considered an in situ development, since the phylogenetic study takes the information – among others – 1) from Parpola and Carpelan, who consider Netted Ware, a culture derived from Fatyanovo/Abashevo and Volosovo, as the culprit of the Finno-Ugric expansion; and 2) from Kallio (2006), who clearly states that Proto-Balto-Finnic (like Proto-Finno-Samic) was spoken around the Gulf of Finland during the Bronze Age. Both of them set the terminus ante quem of the language presence in the Baltic ca. 1900 BC.

Anyways, as a consequence of geneticists keeping these untenable pre-ancient DNA haplogroup-based arguments today, I expect to see this “Finnic” language expansion also described for the Western Baltic, Scandinavia or northern Europe, when this same proportion of hg. N1c and “Nganasan” ancestry is observed in Iron Age samples around the Baltic Sea. The nativist trends that this domination of “Finns” all over Northern Europe 2,500 years ago will create will be even more fun to read than the current ones…

EDIT (10 May 2019) How I see the reaction of many to ancient DNA, in keeping their old theories:

Related

New preprint papers on Finland’s population history and disease, skin pigmentation in Africa, and genetic variation in Thailand hunter-gatherers

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New and interesting research these days in BioRxiv:

Haplotype sharing provides insights into fine-scale population history and disease in Finland, by Martín et al. (2017):

Finland provides unique opportunities to investigate population and medical genomics because of its adoption of unified national electronic health records, detailed historical and birth records, and serial population bottlenecks. We assemble a comprehensive view of recent population history (≤100 generations), the timespan during which most rare disease-causing alleles arose, by comparing pairwise haplotype sharing from 43,254 Finns to geographically and linguistically adjacent countries with different population histories, including 16,060 Swedes, Estonians, Russians, and Hungarians. We find much more extensive sharing in Finns, with at least one ≥ 5 cM tract on average between pairs of unrelated individuals. By coupling haplotype sharing with fine-scale birth records from over 25,000 individuals, we find that while haplotype sharing broadly decays with geographical distance, there are pockets of excess haplotype sharing; individuals from northeast Finland share several-fold more of their genome in identity-by-descent (IBD) segments than individuals from southwest regions containing the major cities of Helsinki and Turku. We estimate recent effective population size changes over time across regions of Finland and find significant differences between the Early and Late Settlement Regions as expected; however, our results indicate more continuous gene flow than previously indicated as Finns migrated towards the northernmost Lapland region. Lastly, we show that haplotype sharing is locally enriched among pairs of individuals sharing rare alleles by an order of magnitude, especially among pairs sharing rare disease causing variants. Our work provides a general framework for using haplotype sharing to reconstruct an integrative view of recent population history and gain insight into the evolutionary origins of rare variants contributing to disease.

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Migration rates and haplotype sharing within Finland and between neighboring countries. A) Map of regional Finnish, Swedish, and Estonian birthplaces Purple triangle indicates St. Petersburg, Russia. Hungary not shown. 1 Finnish, Swedish, and Estonian region labels are shown in Table S3. B) Principal components analysis (PCA) of unrelated individuals, colored by birth region as shown in A) if available or country otherwise. C-D) Migration rates inferred with EEMS. Values and colors indicate inferred rates, for example with +1 (shades of blue) indicating an order of magnitude more migration at a given point on average, and shades of orange indicating migration barriers. C) Migration rates among municipalities in Finland. D) Migration rates within and between Finland, Sweden, Estonia, and St. Petersburg, Russia. Available under a CC-BY 4.0 International license.

Interesting to understand this paper is the whole research published by the Institute for Molecular Medicine Finland (FIMM): their website contains detailed research on Finland’s recent genetic history.

NOTE: The featured image of this article contains three figures from the FIMM (License CC-BY 4.0). Left: Position of the points represents the locations of 1042 Finnish individuals. By clustering the individuals into two groups based on genome data we see a split between eastern (blue) and western (red) parts. Individuals who show considerable relatedness to both groups have been colored with cyan. Both parents of each individual were born close to each other and based on the parents’ birth years we can infer that we are looking at the genetic structure present in Finland before 1950s. Center: An estimated borderline of the Treaty of Nöteborg on top of the map from the left. The border line is drawn between Jääski (28.92 N, 61.04 E) and Pyhäjoki (24.26 N, 64.46 E). Right: The settlement border divides Finland into the early settlement region (to west and south of the border) and the late settlement region (to east and north of the border) (Jutikkala 1933, s. 91). We see that Southern Savo (in south-eastern part of the early settlement) is among the only parts of the early settlement region that is dominated by the eastern genetic group. Information from Matti Pirinen and Sini Kerminen, 24.5.2017.

An Unexpectedly Complex Architecture for Skin Pigmentation in Africans, by Martin et al (2017):

Fewer than 15 genes have been directly associated with skin pigmentation variation in humans, leading to its characterization as a relatively simple trait. However, by assembling a global survey of quantitative skin pigmentation phenotypes, we demonstrate that pigmentation is more complex than previously assumed with genetic architecture varying by latitude. We investigate polygenicity in the Khoe and the San, populations indigenous to southern Africa, who have considerably lighter skin than equatorial Africans. We demonstrate that skin pigmentation is highly heritable, but that known pigmentation loci explain only a small fraction of the variance. Rather, baseline skin pigmentation is a complex, polygenic trait in the KhoeSan. Despite this, we identify canonical and non-canonical skin pigmentation loci, including near SLC24A5, TYRP1, SMARCA2/VLDLR, and SNX13 using a genome-wide association approach complemented by targeted resequencing. By considering diverse, under-studied African populations, we show how the architecture of skin pigmentation can vary across humans subject to different local evolutionary pressures.

Contrasting maternal and paternal genetic variation of hunter-gatherer groups in Thailand, by Kutanan et al. (2017):

The Maniq and Mlabri are the only recorded nomadic hunter-gatherer groups in Thailand. Here, we sequenced complete mitochondrial (mt) DNA genomes and ~2.364 Mbp of non-recombining Y chromosome (NRY) to learn more about the origins of these two enigmatic populations. Both groups exhibited low genetic diversity compared to other Thai populations, and contrasting patterns of mtDNA and NRY diversity: there was greater mtDNA diversity in the Maniq than in the Mlabri, while the converse was true for the NRY. We found basal uniparental lineages in the Maniq, namely mtDNA haplogroups M21a, R21 and M17a, and NRY haplogroup K. Overall, the Maniq are genetically similar to other negrito groups in Southeast Asia. By contrast, the Mlabri haplogroups (B5a1b1 for mtDNA and O1b1a1a1b and O1b1a1a1b1a1 for the NRY) are common lineages in Southeast Asian non-negrito groups, and overall the Mlabri are genetically similar to their linguistic relatives (Htin and Khmu) and other groups from northeastern Thailand. In agreement with previous studies of the Mlabri, our results indicate that the Malbri do not directly descend from the indigenous negritos. Instead, they likely have a recent origin (within the past 1,000 years) by an extreme founder event (involving just one maternal and two paternal lineages) from an agricultural group, most likely the Htin or a closely-related group.

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