Vikings, Vikings, Vikings! “eastern” ancestry in the whole Baltic Iron Age

vikings-middle-age

Open access Population genomics of the Viking world, by Margaryan et al. bioRxiv (2019), with a huge new sampling from the Viking Age.

Interesting excerpts (emphasis mine, modified for clarity):

To understand the genetic structure and influence of the Viking expansion, we sequenced the genomes of 442 ancient humans from across Europe and Greenland ranging from the Bronze Age (c. 2400 BC) to the early Modern period (c. 1600 CE), with particular emphasis on the Viking Age. We find that the period preceding the Viking Age was accompanied by foreign gene flow into Scandinavia from the south and east: spreading from Denmark and eastern Sweden to the rest of Scandinavia. Despite the close linguistic similarities of modern Scandinavian languages, we observe genetic structure within Scandinavia, suggesting that regional population differences were already present 1,000 years ago.

Maps illustrating the following texts have been made based on data from this and other papers:

  • Maps showing ancestry include only data from this preprint (which also includes some samples from Sigtuna).
  • Maps showing haplogroup density include Vikings from other publications, such as those from Sigtuna in Krzewinska et al. (2018), and from Iceland in Ebenesersdóttir et al. (2018).
  • Maps showing haplogroups of ancient DNA samples based on their age include data from all published papers, but with slightly modified locations to avoid overcrowding (randomized distance approx. ± 0.1 long. and lat.).

middle-ages-europe-y-dna
Y-DNA haplogroups in Europe during the Viking expansions (full map). See other maps from the Middle Ages.

We find that the transition from the BA to the IA is accompanied by a reduction in Neolithic farmer ancestry, with a corresponding increase in both Steppe-like ancestry and hunter-gatherer ancestry. While most groups show a slight recovery of farmer ancestry during the VA, there is considerable variation in ancestry across Scandinavia. In particular, we observe a wide range of ancestry compositions among individuals from Sweden, with some groups in southern Sweden showing some of the highest farmer ancestry proportions (40% or more in individuals from Malmö, Kärda or Öland).

Ancestry proportions in Norway and Denmark on the other hand appear more uniform. Finally we detect an influx of low levels of “eastern” ancestry starting in the early VA, mostly constrained among groups from eastern and central Sweden as well as some Norwegian groups. Testing of putative source groups for this “eastern” ancestry revealed differing patterns among the Viking Age target groups, with contributions of either East Asian- or Caucasus-related ancestry.

saami-ancestry-vikings
Ancestry proportions of four-way models including additional putative source groups for target groups for which three-way fit was rejected (p ≤ 0.01);

Overall, our findings suggest that the genetic makeup of VA Scandinavia derives from mixtures of three earlier sources: Mesolithic hunter-gatherers, Neolithic farmers, and Bronze Age pastoralists. Intriguingly, our results also indicate ongoing gene flow from the south and east into Iron Age Scandinavia. Thus, these observations are consistent with archaeological claims of wide-ranging demographic turmoil in the aftermath of the Roman Empire with consequences for the Scandinavian populations during the late Iron Age.

Genetic structure within Viking-Age Scandinavia

We find that VA Scandinavians on average cluster into three groups according to their geographic origin, shifted towards their respective present-day counterparts in Denmark, Sweden and Norway. Closer inspection of the distributions for the different groups reveals additional complexity in their genetic structure.

vikings-danish-ancestry
Natural neighbor interpolation of “Danish ancestry” among Vikings.

We find that the ‘Norwegian’ cluster includes Norwegian IA individuals, who are distinct from both Swedish and Danish IA individuals which cluster together with the majority of central and eastern Swedish VA individuals. Many individuals from southwestern Sweden (e.g. Skara) cluster with Danish present-day individuals from the eastern islands (Funen, Zealand), skewing towards the ‘Swedish’ cluster with respect to early and more western Danish VA individuals (Jutland).

Some individuals have strong affinity with Eastern Europeans, particularly those from the island of Gotland in eastern Sweden. The latter likely reflects individuals with Baltic ancestry, as clustering with Baltic BA individuals is evident in the IBS-UMAP analysis and through f4-statistics.

vikings-norwegian-ancestry
Natural neighbor interpolation of “Norwegian ancestry” among Vikings.

For more on this influx of “eastern” ancestry see my previous posts (including Viking samples from Sigtuna) on Genetic and linguistic continuity in the East Baltic, and on the Pre-Proto-Germanic homeland based on hydrotoponymy.

Baltic ancestry in Gotland

Genetic clustering using IBS-UMAP suggested genetic affinities of some Viking Age individuals with Bronze Age individuals from the Baltic. To further test these, we quantified excess allele sharing of Viking Age individuals with Baltic BA compared to early Viking Age individuals from Salme using f4 statistics. We find that many individuals from the island of Gotland share a significant excess of alleles with Baltic BA, consistent with other evidence of this site being a trading post with contacts across the Baltic Sea.

vikings-finnish-ancestry
Natural neighbor interpolation of “Finnish ancestry” among Vikings.

The earliest N1a-VL29 sample available comes from Iron Age Gotland (VK579) ca. AD 200-400 (see Iron Age Y-DNA maps), which also proves its presence in the western Baltic before the Viking expansion. The distribution of N1a-VL29 and R1a-Z280 (compared to R1a in general) among Vikings also supports a likely expansion of both lineages in succeeding waves from the east with Akozino warrior-traders, at the same time as they expanded into the Gulf of Finland.

vikings-y-dna-haplogroup-r1a-z280-over-r1a
Density of haplogroup R1a-Z280 (samples in pink) overlaid over other R1a samples (in green, with R1a-Z284 in cyan) among Vikings.

Vikings in Estonia

(…) only one Viking raiding or diplomatic expedition has left direct archaeological traces, at Salme in Estonia, where 41 Swedish Vikings who died violently were buried in two boats accompanied by high-status weaponry. Importantly, the Salme boat-burial predates the first textually documented raid (in Lindisfarne in 793) by nearly half a century. Comparing the genomes of 34 individuals from the Salme burial using kinship analyses, we find that these elite warriors included four brothers buried side by side and a 3rd degree relative of one of the four brothers. In addition, members of the Salme group had very similar ancestry profiles, in comparison to the profiles of other Viking burials. This suggests that this raid was conducted by genetically homogeneous people of high status, including close kin. Isotope analyses indicate that the crew descended from the Mälaren area in Eastern Sweden thus confirming that the Baltic-Mid-Swedish interaction took place early in the VA.

vikings-swedish-ancestry
Natural neighbor interpolation of “Swedish ancestry” among Vikings.

Viking samples from Estonia show thus ancient Swedes from the Mälaren area, which proves once again that hg. N1a-VL29 (especially subclade N1a-L550) and tiny proportions of so-called “Siberian ancestry” expanded during the Early Iron Age into the whole Baltic Sea area, not only into Estonia, and evidently not spreading with Balto-Finnic languages (since the language influence is in the opposite direction, east-west, Germanic > Finno-Samic, during the Bronze Age).

N1a-VL29 lineages spread again later eastwards with Varangians, from Sweden into north-eastern Europe, most likely including the ancestors of the Rurikid dynasty. Unsurprisingly, the arrival of Vikings with Swedish ancestry into the East Baltic and their dispersal through the forest zone didn’t cause a language shift of Balto-Finnic, Mordvinic, or East Slavic speakers to Old Norse, either…

NOTE. For N1a-Y4339 – N1a-L550 subclade of Swedish origin – as main haplogroup of modern descendants of Rurikid princes, see Volkov & Seslavin (2019) – full text in comments below. Data from ancient samples show varied paternal lineages even among early rulers traditionally linked to Rurik’s line, which explains some of the discrepancies found among modern descendants:

  • A sample from Chernihiv (VK542) potentially belonging to Gleb Svyatoslavich, the 11th century prince of Tmutarakan/Novgorod, belongs to hg. I2a-Y3120 (a subclade of early Slavic I2a-CTS10228) and has 71% “Modern Polish” ancestry (see below).
  • Izyaslav Ingvarevych, the 13th century prince of Dorogobuzh, Principality of Volhynia/Galicia, is probably behind a sample from Lutsk (VK541), and belongs to hg. R1a-L1029 (a subclade of R1a-M458), showing ca. 95% of “Modern Polish” ancestry.
  • Yaroslav Osmomysl, the 12th century Prince of Halych (now in Western Ukraine), was probably of hg. E1b-V13, yet another clearly early Slavic haplogroup.

vikings-y-dna-haplogroup-n1a
Density of haplogroup N1a-VL29, N1a-L550 (samples in pink, most not visible) among Vikings. Samples of hg. R1b in blue, hg. R1a in green, hg. I in orange.

Finnish ancestry

Firstly, modern Finnish individuals are not like ancient Finnish individuals, modern individuals have ancestry of a population not in the reference; most likely Steppe/Russian ancestry, as Chinese are in the reference and do not share this direction. Ancient Swedes and Norwegians are more extreme than modern individuals in PC2 and 4. Ancient UK individuals were more extreme than Modern UK individuals in PC3 and 4. Ancient Danish individuals look rather similar to modern individuals from all over Scandinavia. By using a supervised ancient panel, we have removed recent drift from the signal, which would have affected modern Scandinavians and Finnish populations especially. This is in general a desirable feature but it is important to check that it has not affected inference.

ancient-modern-finns-steppe
PCA of the ancient and modern samples using the ancient palette, showing different PCs. Modern individuals are grey and the K=7 ancient panel surrogate populations are shown in strong colors, whilst the remaining M-K=7 ancient populations are shown in faded colors.

The story for Modern-vs-ancient Finnish ancestry is consistent, with ancient Finns looking much less extreme than the moderns. Conversely, ancient Norwegians look like less-drifted modern Norwegians; the Danish admixture seen through the use of ancient DNA is hard to detect because of the extreme drift within Norway that has occurred since the admixture event. PC4 vs PC5 is the most important plot for the ancient DNA story: Sweden and the UK (along with Poland, Italy and to an extent also Norway) are visibly extremes of a distribution the same “genes-mirror-geography” that was seen in the Ancient-palette analysis. PC1 vs PC2 tells the same story – and stronger, since this is a high variance-explained PC – for the UK, Poland and Italy.

Uniform manifold approximation and projection (UMAP) analysis of the VA and other ancient samples.

Evidence for Pictish Genomes

The four ancient genomes of Orkney individuals with little Scandinavian ancestry may be the first ones of Pictish people published to date. Yet a similar (>80% “UK ancestry) individual was found in Ireland (VK545) and five in Scandinavia, implying that Pictish populations were integrated into Scandinavian culture by the Viking Age.

Our interpretation for the Orkney samples can be summarised as follows. Firstly, they represent “native British” ancestry, rather than an unusual type of Scandinavian ancestry. Secondly, that this “British” ancestry was found in Britain before the Anglo-Saxon migrations. Finally, that in Orkney, these individuals would have descended from Pictish populations.

vikings-british-ancestry
Natural neighbor interpolation of “British ancestry” among Vikings.

(…) ‘UK’ represents a group from which modern British and Irish people all receive an ancestry component. This information together implies that within the sampling frame of our data, they are proxying the ‘Briton’ component in UK ancestry; that is, a pre-Roman genetic component present across the UK. Given they were found in Orkney, this makes it very likely that they were descended from a Pictish population.

Modern genetic variation within the UK sees variation between ‘native Briton’ populations Wales, Scotland, Cornwall and Ireland as large compared to that within the more ‘Anglo-Saxon’ English. This is despite subsequent gene flow into those populations from English-like populations. We have not attempted to disentangle modern genetic drift from historically distinct populations. Roman-era period people in England, Wales, Ireland and Scotland may not have been genetically close to these Orkney individuals, but our results show that they have a shared genetic component as they represent the same direction of variation.

Density of haplogroup R1b-L21 (samples in red), overlaid over all samples of hg. R1b among Vikings (R1b-U106 in green, other R1b-L151 in deep red). To these samples one may add the one from Janakkala in south-western Finland (AD ca. 1300), of hg. R1b-L21, possibly related to these population movements.

For more on Gaelic ancestry and lineages likely representing slaves among early Icelanders, see Ebenesersdóttir et al. (2018).

Y-DNA

As in the case of mitochondrial DNA, the overall distribution profile of the Y chromosomal haplogroups in the Viking Age samples was similar to that of the modern North European populations. The most frequently encountered male lineages were the haplogroups I1, R1b and R1a.

Haplogroup I (I1, I2)

The distribution of I1 in southern Scandinavia, including a sample from Sealand (VK532) ca. AD 100 (see Iron Age Y-DNA maps) proves that it had become integrated into the West Germanic population already before their expansions, something that we already suspected thanks to the sampling of Germanic tribes.

vikings-y-dna-haplogroup-i
Density of haplogroup I (samples in orange) among Vikings. Samples of hg. R1b in blue, hg. R1a in green, N1a in pink.
vikings-y-dna-haplogroup-i1-over-i
Density of haplogroup I1 (samples in red) overlaid over all samples of hg. I among Vikings.

Haplogroup R1b (M269, U106, P312)

Especially interesting is the finding of R1b-L151 widely distributed in the historical Nordic Bronze Age region, which is in line with the estimated TMRCA for R1b-P312 subclades found in Scandinavia, despite the known bottleneck among Germanic peoples under U106. Particularly telling in this regard is the finding of rare haplogroups R1b-DF19, R1b-L238, or R1b-S1194. All of that points to the impact of Bell Beaker-derived peoples during the Dagger period, when Pre-Proto-Germanic expanded into Scandinavia.

Also interesting is the finding of hg. R1b-P297 in Troms, Norway (VK531) ca. 2400 BC. R1b-P297 subclades might have expanded to the north through Finland with post-Swiderian Mesolithic groups (read more about Scandinavian hunter-gatherers), and the ancestry of this sample points to that origin.

However, it is also known that ancestry might change within a few generations of admixture, and that the transformation brought about by Bell Beakers with the Dagger Period probably reached Troms, so this could also be a R1b-M269 subclade. In fact, the few available data from this sample show that it comes from the natural harbour Skarsvågen at the NW end of the island Senja, and that its archaeologist thought it was from the Viking period or slightly earlier, based on the grave form. From Prescott (2017):

In 1995, Prescott and Walderhaug tentatively argued that a dramatic transformation took place in Norway around the Late Neolithic (2350 BCE), and that the swift nature of this transition was tied to the initial Indo-Europeanization of southern and coastal Norway, at least to Trøndelag and perhaps as far north as Troms. (…)

The Bell Beaker/early Late Neolithic, however, represents a source and beginning of these institution and practices, exhibits continuity to the following metal age periods and integrated most of Northern Europe’s Nordic region into a set of interaction fields. This happened around 2400 BCE, at the MNB to LN transition.

NOTE. This particular sample is not included in the maps of Viking haplogroups.

vikings-y-dna-haplogroup-r1b
Density of haplogroup R1b (samples in blue) among Vikings. Samples of hg. I in orange, hg. R1a in green, N1a in pink.
vikings-y-dna-haplogroup-r1b-U106-over-r1b
Density of haplogroup R1b-U106 (samples in green) overlaid over all samples of hg. R1b (other R1b-L23 samples in red) among Vikings.
vikings-y-dna-haplogroup-r1b-P312-over-r1b
Density of R1b-L151 (xR1b-U106) (samples in deep red) overlaid over all samples of hg. R1b (R1b-U106 in green, other R1b-M269 in blue) among Vikings.

Haplogroup R1a (M417, Z284)

The distribution of hg. R1a-M417, in combination with data on West Germanic peoples, shows that it was mostly limited to Scandinavia, similar to the distribution of I1. In fact, taking into account the distribution of R1a-Z284 in particular, it seems even more isolated, which is compatible with the limited impact of Corded Ware in Denmark or the Northern European Plain, and the likely origin of R1a-Z284 in the expansion with Battle Axe from the Gulf of Finland. The distribution of R1a-Z280 (see map above) is particularly telling, with a distribution around the Baltic Sea mostly coincident with that of N1a.

vikings-y-dna-haplogroup-r1a
Density of haplogroup R1a (samples in green) among Vikings. Samples of hg. R1b in blue, of hg. I in orange, N1a in pink.
vikings-y-dna-haplogroup-r1a-z284-over-r1a
Density of haplogroup R1a-Z284 (samples in cyan) overlaid over all samples of hg. R1a (in green, with R1a-Z280 in pink) among Vikings.

Other haplogroups

Among the ancient samples, two individuals were derived haplogroups were identified as E1b1b1-M35.1, which are frequently encountered in modern southern Europe, Middle East and North Africa. Interestingly, the individuals carrying these haplogroups had much less Scandinavian ancestry compared to the most samples inferred from haplotype based analysis. A similar pattern was also observed for less frequent haplogroups in our ancient dataset, such as G (n=3), J (n=3) and T (n=2), indicating a possible non-Scandinavian male genetic component in the Viking Age Northern Europe. Interestingly, individuals carrying these haplogroups were from the later Viking Age (10th century and younger), which might indicate some male gene influx into the Viking population during the Viking period.

vikings-italian-ancestry
Natural neighbor interpolation of “Italian ancestry” among Vikings.

As the paper says, the small sample size of rare haplogroups cannot distinguish if these differences are statistically relevant. Nevertheless, both E1b samples have substantial Modern Polish-like ancestry: one sample from Gotland (VK474), of hg. E1b-L791, has ca. 99% “Polish” ancestry, while the other one from Denmark (VK362), of hg. E1b-V13, has ca. 35% “Polish”, ca. 35% “Italian”, as well as some “Danish” (14%) and minor “British” and “Finnish” ancestry.

Given the E1b-V13 samples of likely Central-East European origin among Lombards, Visigoths, and especially among Early Slavs, and the distribution of “Polish” ancestry among Viking samples, VK362 is probably a close description of the typical ancestry of early Slavs. The peak of Modern Polish-like ancestry around the Upper Pripyat during the (late) Viking Age suggests that Poles (like East Slavs) have probably mixed since the 10th century with more eastern peoples close to north-eastern Europeans, derived from ancient Finno-Ugrians:

vikings-polish-ancestry
Natural neighbor interpolation of “Polish ancestry” among Vikings.

Similarly, the finding of R1a-M458 among Vikings in Funen, Denmark (VK139), in Lutsk, Poland (VK541), and in Kurevanikha, Russia (VK160), apart from the early Slav from Usedom, may attest to the origin of the spread of this haplogroup in the western Baltic after the Bell Beaker expansion, once integrated in both Germanic and probably Balto-Slavic populations, as well as intermediate Bronze Age peoples that were eventually absorbed by their expansions. This contradicts, again, my simplistic initial assessment of R1a-M458 expansion as linked exclusively (or even mainly) to Balto-Slavs.

antiquity-europe-y-dna
Y-DNA haplogroups in Europe during Antiquity (full map). See other maps of cultures and ancient DNA from Antiquity.

Related

Arrival of steppe ancestry with R1b-P312 in the Mediterranean: Balearic Islands, Sicily, and Iron Age Sardinia

steppe-balearic-sicily-sardinia

New preprint The Arrival of Steppe and Iranian Related Ancestry in the Islands of the Western Mediterranean by Fernandes, Mittnik, Olalde et al. bioRxiv (2019)

Interesting excerpts (emphasis in bold; modified for clarity):

Balearic Islands: The expansion of Iberian speakers

Mallorca_EBA dates to the earliest period of permanent occupation of the islands at around 2400 BCE. We parsimoniously modeled Mallorca_EBA as deriving 36.9 ± 4.2% of her ancestry from a source related to Yamnaya_Samara; (…). We next used qpAdm to identify “proximal” sources for Mallorca_EBA’s ancestry that are more closely related to this individual in space and time, and found that she can be modeled as a clade with the (small) subset of Iberian Bell Beaker culture associated individuals who carried Steppe-derived ancestry (p=0.442).

Suppl. Materials: The model used was with Bell_Beaker_Iberia_highsteppe, a group of outliers from Iberia buried in a Bell Beaker mortuary context who unlike most individuals from this context in that region had high proportions of Steppe ancestry (p=0.442).

Our estimates of Steppe ancestry in the two later Balearic Islands individuals are lower than the earlier one: 26.3 ± 5.1% for Formentera_MBA and 23.1 ± 3.6% for Menorca_LBA, but the Middle to Late Bronze Age Balearic individuals are not a clade relative to non-Balearic groups. Specifically, we find that f4(Mbuti.DG, X; Formentera_MBA, Menorca_LBA) is positive when X=Iberia_Chalcolithic (Z=2.6) or X=Sardinia_Nuragic_BA (Z=2.7). While it is tempting to interpret the latter statistic as suggesting a genetic link between peoples of the Talaiotic culture of the Balearic islands and the Nuragic culture of Sardinia, the attraction to Iberia_Chalcolithic is just as strong, and the mitochondrial haplogroup U5b1+16189+@16192 in Menorca_LBA is not observed in Sardinia_Nuragic_BA but is observed in multiple Iberia_Chalcolithic individuals. A possible explanation is that both the ancestors of Nuragic Sardinians and the ancestors of Talaiotic people from the Balearic Islands received gene flow from an unsampled Iberian Chalcolithic-related group (perhaps a mainland group affiliated to both) that did not contribute to Formentera_MBA.

This sample, like another one in El Argar, is of hg. R1b-P312. So there you are, the data that connects the Proto-Iberian expansion (replacing IE-speaking Bell Beakers) to the Iberian Chalcolithic population, signaled by the increase in Iberian Chalcolithic ancestry after the arrival of Bell Beakers, most likely connected originally to the Argaric and post-Argaric expansions during the MBA.

balearic-sicily-sardinia-pca
PCA with previously published ancient individuals (non-filled symbols), projected onto variation from present-day populations (gray squares).

Steppe in Sardinia IA: Phocaeans from Italy?

Most Sardinians buried in a Nuragic Bronze Age context possessed uniparental haplogroups found in European hunter-gatherers and early farmers, including Y-haplogroup R1b1a[xR1b1a1a] which is different from the characteristic R1b1a1a2a1a2 spread in association with the Bell Beaker complex. An exception is individual I10553 (1226-1056 calBCE) who carried Y-haplogroup J2b2a, previously observed in a Croatian Middle Bronze Age individual bearing Steppe ancestry, suggesting the possibility of genetic input from groups that arrived from the east after the spread of first farmers. This is consistent with the evidence of material culture exchange between Sardinians and mainland Mediterranean groups, although genome-wide analyses find no significant evidence of Steppe ancestry so the quantitative demographic impact was minimal.

Another interesting data, these (Mesolithic) remnant R1b-V88 lineages closely related to the Italian Peninsula, the most likely region of expansion of these lineages into Africa, in turn possibly connected to the expansion of Proto-Afroasiatic.

We detect definitive evidence of Iranian-related ancestry in an Iron Age Sardinian I10366 (391-209 calBCE) with an estimate of 11.9 ± 3.7.% Iran_Ganj_Dareh_Neolithic related ancestry, while rejecting the model with only Anatolian_Neolithic and WHG at p=0.0066 (Supplementary Table 9). The only model that we can fit for this individual using a pair of populations that are closer in time is as a mixture of Iberia_Chalcolithic (11.9 ± 3.2%) and Mycenaean (88.1 ± 3.2%) (p=0.067). This model fits even when including Nuragic Sardinians in the outgroups of the qpAdm analysis, which is consistent with the hypothesis that this individual had little if any ancestry from earlier Sardinians.

yamnaya-samara
Proportions of ancestry using a distal qpAdm framework on an individual basis (a), and based on qpWave clusters

Sicily EBA: The Lusitanian/Ligurian connection?

(…) While a previously reported Bell Beaker culture-associated individual from Sicily had no evidence of Steppe ancestry, (…) we find evidence of Steppe ancestry in the Early Bronze Age by ~2200 BCE. In distal qpAdm, the outlier Sicily_EBA11443 is parsimoniously modeled as harboring 40.2 ± 3.5% Steppe ancestry, and the outlier Sicily_EBA8561 is parsimoniously modeled as harboring 23.3 ± 3.5% Steppe ancestry. (…) The presence of Steppe ancestry in Early Bronze Age Sicily is also evident in Y chromosome analysis, which reveals that 4 of the 5 Early Bronze Age males had Steppe-associated Y-haplogroup R1b1a1a2a1a2. (Online Table 1). Two of these were Y-haplogroup R1b1a1a2a1a2a1 (Z195) which today is largely restricted to Iberia and has been hypothesized to have originated there 2500-2000 BCE. This evidence of west-to-east gene flow from Iberia is also suggested by qpAdm modeling where the only parsimonious proximate source for the Steppe ancestry we found in the main Sicily_EBA cluster is Iberians.

What’s this? An ancestral connection between Sicel Elymian and Galaico-Lusitanian or Ligurian (based on an origin in NE Iberia)? Impossible to say, especially if the languages of these early settlers were replaced later by non-Indo-European speakers from the eastern Mediterranean, and by Indo-European speakers from the mainland closely related to Proto-Italic during the LBA, but see below.

Regarding the comment on R1b-Z195, it is associated with modern Iberians, as DF27 in general, due to founder effects beyond the Pyrenees. It is a very old subclade, split directly from DF27 roughly at the same time as it split from the parent P312, i.e. it can be found anywhere in Europe, and it almost certainly accompanied the expansion of Celts from Central Europe under the subclade R1b-M167/SRY2627.

The connection is thus strong only because of the qpAdm modeling, since R1b-DF27 and subclade R1b-Z195 are certainly lineages expanded quite early, most likely with Yamna settlers in Hungary and East Bell Beakers.

In this case, if stemming from Iberia, it is most likely of subclade R1b-Z220 – or another Z195 (xM167) lineage – originally associated with the Old European substrate found in topo-hydronymy in Iberia, whose most likely remnants attested during the Iron Age were Lusitanians.

r1b-df27-z195
Left: Modern distribution of R1b-Z195 (YFull estimate 2700 BC); Right: Modern distribution of DF27. Both include later founder effects within Iberia, so the increase in the Basque country and the Crown of Aragon and the decrease in Portugal can safely be ignored. Contour maps of the derived allele frequencies of the SNPs analyzed in Solé-Morata et al. (2017).

We detect Iranian-related ancestry in Sicily by the Middle Bronze Age 1800-1500 BCE, consistent with the directional shift of these individuals toward Mycenaeans in PCA. Specifically, two of the Middle Bronze Age individuals can only be fit with models that in addition to Anatolia_Neolithic and WHG, include Iran_Ganj_Dareh_Neolithic. The most parsimonious model for Sicily_MBA3125 has 18.0 ± 3.6% Iranian-related ancestry (p=0.032 for rejecting the alternative model of Steppe rather than Iranian-related ancestry), and the most parsimonious model for Sicily_MBA has 14.9 ± 3.9% Iranian-related ancestry (p=0.037 for rejecting the alternative model).

The modern southern Italian Caucasus-related signal identified in Raveane et al. (2018) is plausibly related to the same Iranian-related spread of ancestry into Sicily that we observe in the Middle Bronze Age (and possibly the Early Bronze Age).

The non-Indo-European Sicanians and Elymians were possibly then connected to eastern Mediterranean groups before the expansion of the Sea Peoples.

For the Late Bronze Age group of individuals, qpAdm documented Steppe-related ancestry, modeling this group as 80.2 ± 1.8% Anatolia_Neolithic, 5.3 ± 1.6% WHG, and 14.5 ± 2.2% Yamnaya_Samara. Our modeling using sources more closely related in space and time also supports Sicily_LBA having Minoan-related ancestry or being derived from local preceding populations or individuals with ancestries similar to those of Sicily_EBA3123 (p=0.527), Sicily_MBA3124 (p=0.352), and Sicily_MBA3125 (p=0.095).

This increase in Steppe-related ancestry in a western site during the LBA most likely represents either an expansion from the Aegean or – maybe more likely, given the archaeological finds – a regional population similar to Sicily EBA re-emerging or rather being displaced from the eastern part of the island because of a westward movement from nearby Calabria.

Whether this population sampled spoke Indo-European or not at this time is questionable, since the Iron Age accounts show non-IE Elymians in this region.

Actually, Elymians seem to have spoken Indo-European, which fits well with the increase in steppe ancestry.

EDIT (21 MAR): Interesting about a proposed incoming Minoan-like ancestry is the potential origin of the Iran Neolithic-related ancestry that is going to appear in Central Italy during the LBA. This could then be potentially associated with Tyrsenians passing through the area, although the traditional description may be more more compatible with an arrival of Sea Peoples from the Adriatic.

Sad to read this:

This manuscript is dedicated to the memory of Sebastiano Tusa of the Soprintendenza del Mare in Palermo, who would have been an author of this study had he not tragically died in the crash of Ethiopia Airlines flight 302 on March 10.

Related

Aquitanians and Iberians of haplogroup R1b are exactly like Indo-Iranians and Balto-Slavs of haplogroup R1a

eba-indo-iranian-balto-slavs

The final paper on Indo-Iranian peoples, by Narasimhan and Patterson (see preprint), is soon to be published, according to the first author’s Twitter account.

One of the interesting details of the development of Bronze Age Iberian ethnolinguistic landscape was the making of Proto-Iberian and Proto-Basque communities, which we already knew were going to show R1b-P312 lineages, a haplogroup clearly associated during the Bell Beaker period with expanding North-West Indo-Europeans:

From the Bronze Age (~2200–900 BCE), we increase the available dataset from 7 to 60 individuals and show how ancestry from the Pontic-Caspian steppe (Steppe ancestry) appeared throughout Iberia in this period, albeit with less impact in the south. The earliest evidence is in 14 individuals dated to ~2500–2000 BCE who coexisted with local people without Steppe ancestry. These groups lived in close proximity and admixed to form the Bronze Age population after 2000 BCE with ~40% ancestry from incoming groups. Y-chromosome turnover was even more pronounced, as the lineages common in Copper Age Iberia (I2, G2, and H) were almost completely replaced by one lineage, R1b-M269.

iberia-admixture-y-dna
Proportion of ancestry derived from central European Beaker/Bronze Age populations in Iberians from the Middle Neolithic to the Iron Age (table S15). Colors indicate the Y-chromosome haplogroup for each male. Red lines represent period of admixture. Modified from Olalde et al. (2019).

The arrival of East Bell Beakers speaking Indo-European languages involved, nevertheless, the survival of the two non-IE communities isolated from each other – likely stemming from south-western France and south-eastern Iberia – thanks to a long-lasting process of migration and admixture. There are some common misconceptions about ancient languages in Iberia which may have caused some wrong interpretations of the data in the paper and elsewhere:

NOTE. A simple reading of Iberian prehistory would be enough to correct these. Two recent books on this subject are Villar’s Indoeuropeos, iberos, vascos y otros parientes and Vascos, celtas e indoeuropeos. Genes y lenguas.

Iberian languages were spoken at least in the Mediterranean and the south (ca. “1/3 of Iberia“) during the Bronze Age.

Nope, we only know the approximate location of Iberian culture and inscriptions from the Late Iron Age, and they occupy the south-eastern and eastern coastal areas, but before that it is unclear where they were spoken. In fact, it seems evident now that the arrival of Urnfield groups from the north marks the arrival of Celtic-speaking peoples, as we can infer from the increase in Central European admixture, while the expansion of anthropomorphic stelae from the north-west must have marked the expansion of Lusitanian.

Vasconic was spoken in both sides of the Pyrenees, as it was in the Middle Ages.

Wrong. One of the worst mistakes I am seeing in many comments since the paper was published, although admittedly the paper goes around this problem talking about “Modern Basques”. Vasconic toponyms appear south of the Pyrenees only after the Roman conquests, and tribes of the south-western Pyrenees and Cantabrian regions were likely Celtic-speaking peoples. Aquitanians (north of the western Pyrenees) are the only known ancient Vasconic-speaking population in proto-historic times, ergo the arrival of Bell Beakers in Iberia was most likely accompanied by Indo-European languages which were later replaced by Celtic expanding from Central Europe, and Iberian expanding from south-east Iberia, and only later with Latin and Vasconic.

Ligurian is non-Indo-European, and Lusitanian is Celtic-like, so Iberia must have been mostly non-Indo-European-speaking.

The fragmentary material available on Ligurian is enough to show that phonetically it is a NWIE dialect of non-Celtic, non-Italic nature, much like Lusitanian; that is, unless you follow laryngeals up to Celtic or Italic, in which case you can argue anything about this or any other IE language, as people who reconstruct laryngeals for Baltic in the common era do.

EDIT (19 Mar 2019): It was not clear enough from this paragraph, because Ligurian-like languages in NE Iberia is just a hypothesis based on the archaeological connection of the whole southern France Bell Beaker region. My aim was to repeat the idea that Old European hydro-toponymy is older in NE Iberia (as almost anywhere in Iberia) than Iberian toponymy, so the initial hypothesis is that:

  1. a Palaeo-European language (as Villar puts it) expanded into most regions of Iberia in ancient times (he considered at some point the Mesolithic, but that is obviously wrong, as we know now); then
  2. Celts expanded at least to the Ebro River Basin; then
  3. Iberians expanded to the north and replaced these in NE Iberia; and only then
  4. after the Roman invasion, around the start of the Common Era, appear Vasconic toponyms south of the Pyrenees.

Lusitanian obviously does not qualify as Celtic, lacking the most essential traits that define Celticness…Unless you define “(Para-)Celtic” as Pre-Proto-Celtic-like, or anything of the sort to support some Atlantic continuity, in which case you can also argue that Pre-Italic or Pre-Germanic are Celtic, because you would be essentially describing North-West Indo-European

If Basques have R1b, it’s because of a culture of “matrilocality” as opposed to the “patrilocality” of Indo-Europeans

So wrong it hurts my eyes every time I read this. Not only does matrilocality in a regional group have few known effects in genetics, but there are many well-documented cases of population replacement (with either ancestry or Y-DNA haplogroups, or both) without language replacement, without a need to resort to “matrilineality” or “matrilocality” or any other cultural difference in any of these cases.

In fact, it seems quite likely now that isolated ancient peoples north of the Pyrenees will show a gradual replacement of surviving I2a lineages by neighbouring R1b, while early Iberian R1b-DF27 lineages are associated with Lusitanians, and later incoming R1b-DF27 lineages (apart from other haplogroups) are most likely associated with incoming Celts, which must have remained in north-central and central-east European groups.

NOTE. Notice how R1a is fully absent from all known early Indo-European peoples to date, whether Iberian IE, British IE, Italic, or Greek. The absence of R1a in Iberia after the arrival of Celts is even more telling of the origin of expanding Celts in Central Europe.

I haven’t had enough time to add Iberian samples to my spreadsheet, and hence neither to the ASoSaH texts nor maps/PCAs (and I don’t plan to, because it’s more efficient for me to add both, Asian and Iberian samples, at the same time), but luckily Maciamo has summed it up on Eupedia. Or, graphically depicted in the paper for the southeast:

iberia-haplogroups
Y chromosome haplogroup composition of individuals from southeast Iberia during the past 2000 years. The general Iberian Bronze and Iron Age population is included for comparison. Modified from Olalde et al. (2019).

Does this continued influx of Y-DNA haplogroups in Iberia with different cultures represent permanent changes in language? Are, therefore, modern Iberian languages derived from Lusitanian, Sorothaptic/Celtic, Greek, Phoenician, East or West Germanic, Hebrew, Berber, or Arabic languages? Obviously not. Same with Italy (see the recent preprint on modern Italians by Raveane et al. 2018), with France, with Germany, or with Greece.

If that happens in European regions with a known ancient history, why would the recent expansions and bottlenecks of R1b in modern Basques (or N1c around the Baltic, or R1a in Slavs) in the Middle Ages represent an ancestral language surviving into modern times?

Indo-Iranians

If something is clear from Narasimhan, Patterson, et al. (2018), is that we know finally the timing of the introduction and expansion of R1a-Z645 lineages among Indo-Iranians.

We could already propose since 2015 that a slow admixture happened in the steppes, based on archaeological finds, due to settlement elites dominating over common peoples, coupled with the known Uralic linguistic traits of Indo-Iranian (and known Indo-Iranian influence on Finno-Ugric) – as I did in the first version of the Indo-European demic diffusion model.

The new huge sampling of Sintashta – combined with that of Catacomb, Poltavka, Potapovka, Andronovo, and Srubna – shows quite clearly how this long-term admixture process between Uralic peoples and Indo-Iranians happened between forest-steppe CWC (mainly Abashevo) and steppe groups. The situation is not different from that of Iberia ca. 2500-2000 BC; from Narasimhan, Patterson, et al. (2018):

We combined the newly reported data from Kamennyi Ambar 5 with previously reported data from the Sintashta 5 individuals (10). We observed a main cluster of Sintashta individuals that was similar to Srubnaya, Potapovka, and Andronovo in being well modeled as a mixture of Yamnaya-related and Anatolian Neolithic (European agriculturalist-related) ancestry.

Even with such few words referring to one of the most important data in the paper about what happened in the steppes, Wang et al. (2018) help us understand what really happened with this simplistic concept of “steppe ancestry” regarding Yamna vs. Corded Ware differences:

anatolia-neolithic-steppe-eneolithic
Image modified from Wang et al. (2018). Marked are: in red, approximate limit of Anatolia_Neolithic ancestry found in Yamna populations; in blue, Corded Ware-related groups. “Modelling results for the Steppe and Caucasus 1128 cluster. Admixture proportions based on (temporally and geographically) distal and proximal models, showing additional Anatolian farmer-related ancestry in Steppe groups as well as additional gene flow from the south in some of the Steppe groups as well as the Caucasus groups (see also Supplementary Tables 10, 14 and 20).”

As with Iberia (or any prehistoric region), the details of how exactly this language change happened are not evident, but we only need a plausible explanation coupled with archaeology and linguistics. Poltavka, Potapovka, and Sintashta samples – like the few available Iberian ones ca. 2500-2000 BC – offer a good picture of the cohabitation of R1b-L23 (mainly Z2103) and R1a-Z645 (mainly Z93+): a glimpse at the likely presence of R1a-Z93 within settlements – which must have evolved as the dominant elites – in a society where the majority of the population was initially formed by nomad herders (probably most R1b-Z2103), who were usually buried outside of the main settlements.

Will the upcoming Narasimhan, Patterson et al. (2019) deal with this problem of how R1a-M417 replaced R1b-M269, and how the so-called “Steppe_MLBA” (i.e. Corded Ware) ancestry admixed with “Steppe_EMBA” (i.e. Yamnaya) ancestry in the steppes, and which one of their languages survived in the region (that is, the same the Reich Lab has done with Iberia)? Not likely. The ‘genetic wars’ in Iberia deal with haplogroup R1b-P312, and how it was neither ‘native’ nor associated with Basques and non-Indo-European peoples in general. The ‘genetic wars’ in South Asia are concerned with the steppe origin of R1a, to prove that it is not a ‘native’ haplogroup to India, and thus neither are Indo-Aryan languages. To each region a politically correct account of genetic finds, with enough care not to fully dismiss national myths, it seems.

NOTE. Funnily enough, these ‘genetic wars’ are the making of geneticists since the 1990s and 2000s, so we are still in the midst of mostly internal wars caused by what they write. Just as genetic papers of the 2020s will most likely be a reaction to what they are writing right now about “steppe ancestry” and R1a. You won’t find much change to the linguistic reconstruction in this whole period, except for the most multicolored glottochronological proposals…

The first author of the paper has engaged, as far as I could see in Twitter, in dialogue with Hindu nationalists who try to dismiss the arrival of steppe ancestry and R1a into South Asia as inconclusive (to support the potential origin of Sanskrit millennia ago in the Indus Valley Civilization). How can geneticists deal with the real problem here (the original ethnolinguistic group expanding with Corded Ware), when they have to fend off anti-steppists from Europe and Asia? How can they do it, when they themselves are part of the same societies that demand a politically correct presentation of data?

This is how the data on the most likely Indo-Iranian-speaking region should be presented in an ideal world, where – as in the Iberia paper – geneticists would look closely to the Volga-Ural region to discover what happened with Proto-Indo-Iranians from their earliest to their latest stage, instead of constantly looking for sites close to the Indus Valley to demonstrate who knows what about modern Indian culture:

indo-iranian-admixture-similar-iberians
Tentative map of the Late PIE and Indo-Iranian community in the Volga-Ural steppes since the Eneolithic. Proportion of ancestry derived from central European Corded Ware peoples. Colors indicate the Y-chromosome haplogroup for each male. Red lines represent period of admixture. Modified from Olalde et al. (2019).

Now try and tell Hindu nationalists that Sanskrit expanded from an Early Bronze Age steppe community of R1b-rich nomadic herders that spoke Pre-Indo-Iranian, which was dominated and eventually (genetically) mostly replaced by elite Uralic-speaking R1a peoples from the Russian forest, hence the known phonetic (and some morphological) traits that remained. Good luck with the Europhobic shitstorm ahead..

Balto-Slavic

Iberian cultures, already with a majority of R1b lineages, show a clear northward expansion over previously Urnfield-like groups of north-east Iberia and Mediterranean France (which we now know probably represent the migration of Celts from central Europe). Similarly, Eastern Balts already under a majority of R1a lineages expanded likely into the Baltic region at the same time as the outlier from Turlojiškė (ca. 1075 BC), which represents the first obvious contacts of central-east Europe with the Baltic.

Iberia shows a more recent influx of central and eastern Mediterranean peoples, one of which eventually succeeded in imposing their language in Western Europe: Romans were possibly associated mainly with R1b-U152, apart from many other lineages. Proto-Slavs probably expanded later than Celts, too, connected to the disintegration of the Lusatian culture, and they were at some point associated with R1a-M458 and R1a-Z280(xZ92) lineages, apart from others already found in Early Slavs.

pca-balto-slavs-tollense-valley
PCA of central-eastern European groups which may have formed the Balto-Slavic-speaking community derived from Bell Beaker, evident from the position ‘westwards’ of CWC in the PCA, and surrounding cultures. Left: Early Bronze Age. Right: Tollense Valley samples.

This parallel between Iberia and eastern Europe is no coincidence: as Europe entered the Bronze Age, chiefdom-based systems became common, and thus the connection of ancestry or haplogroups with ethnolinguistic groups became weaker.

What happened earlier (and who may represent the Pre-Balto-Slavic community) will be clearer when we have enough eastern European samples, but basically we will be able to depict this admixture of NWIE-speaking BBC-derived peoples with Uralic-speaking CWC-derived groups (since Uralic is known to have strongly influenced Balto-Slavic), similar to the admixture found in Indo-Iranians, more or less like this:

iberian-admixture-balto-slavic
Tentative map of the North-West Indo-European and Balto-Slavic community in central-eastern Europe since the East Bell Beaker expansion. Proportion of ancestry derived from Corded Ware peoples. Colors indicate the Y-chromosome haplogroup for each male. Red lines represent period of admixture. Modified from Olalde et al. (2019).

The Early Scythian period marked a still stronger chiefdom-based system which promoted the creation of alliances and federation-like groups, with an earlier representation of the system expanding from north-eastern Europe around the Baltic Sea, precisely during the spread of Akozino warrior-traders (in turn related to the Scythian influence in the forest-steppes), who are the most likely ancestors of most N1c-V29 lineages among modern Germanic, Balto-Slavic, and Volga-Finnic peoples.

Modern haplogroup+language = ancient ones?

It is not difficult to realize, then, that the complex modern genetic picture in Eastern Europe and around the Urals, and also in South Asia (like that of the Aegean or Anatolia) is similar to the Iron Age / medieval Iberian one, and that following modern R1a as an Indo-European marker just because some modern Indo-European-speaking groups showed it was always a flawed methodology; as flawed as following R1b for ancient Vasconic groups, or N1c for ancient Uralic groups.

Why people would argue that haplogroups mean continuity (e.g. R1b with Basques, N1c with Finns, R1a with Slavs, etc.) may be understood, if one lives still in the 2000s. Just like why one would argue that Corded Ware is Indo-European, because of Gimbutas’ huge influence since the 1960s with her myth of “Kurgan peoples”. Not many denied these haplogroup associations, because there was no reason to do it, and those who did usually aligned with a defense of descriptive archaeology.

However, it is a growing paradox that some people interested in genetics today would now, after the Iberian paper, need to:

  • accept that ancient Iberians and probably Aquitanians (each from different regions, and probably from different “Basque-Iberian dialects” in the Chalcolithic, if both were actually related) show eventually expansions with R1b-L23, the haplogroup most obviously associated with expanding Indo-Europeans;
  • acknowledge that modern Iberians have many different lineages derived from prehistoric or historic peoples (Celts, Phoenicians, Greeks, Romans, Jews, Goths, Berbers, Arabs), which have undergone different bottlenecks, the last ones during the Reconquista, but none of their languages have survived;
  • realize that a similar picture is to be found everywhere in central and western Europe since the first proto-historic records, with language replacement in spite of genetic continuity, such as the British Isles (and R1b-L21 continuity) after the arrival of Celts, Romans, Anglo-Saxons, Vikings, or Normans;
  • but, at the same time, continue blindly asserting that haplogroup R1a + “steppe ancestry” represent some kind of supernatural combination which must show continuity with their modern Indo-Iranian or Balto-Slavic language from time immemorial.
sintashta-y-dna
Replacement of R1b-L23 lineages during the Early Bronze Age in eastern Europe and in the Eurasian steppes: emergence of R1a in previous Yamnaya and Bell Beaker territories. Modified from EBA Y-DNA map.

Behave, pretty please

The ‘conservative’ message espoused by some geneticists and amateur genealogists here is basically as follows:

  • Let’s not rush to new theories that contradict the 2000s, lest some people get offended by granddaddy not being these pure whatever wherever as they believed, and let’s wait some 5, 10, or 20 years, as long as necessary – to see if some corner of the Yamna culture shows R1a, or some region in north-eastern Europe shows N1c, or some Atlantic Chalcolithic sample shows R1b – to challenge our preferred theories, if we actually need to challenge anything at all, because it hurts too much.
  • Just don’t let many of these genetic genealogists or academics of our time be unhappy, pretty please with sugar on top, and let them slowly adapt to reality with more and more pet theories to fit everything together (past theories + present data), so maybe when all of them are gone, within 50 or 70 years, society can smoothly begin to move on and propose something closer to reality, but always as politically correct as possible for the next generations.
  • For starters, let’s discuss now (yet again) that Bell Beakers may not have been Indo-European at all, despite showing (unlike Corded Ware) clearly Yamna male lineages and ancestry, because then Corded Ware and R1a could not have been Indo-European and that’s terrible, so maybe Bell Beakers are too brachycephalic to speak Indo-European or something, or they were stopped by the Fearsome Tisza River, or they are not pure Dutch Single Grave in The South hence not Indo-European, or whatever, and that’s why Iron Age Iberians or Etruscans show non-Indo-European languages. That’s not disrespectful to the history of certain peoples, of course not, but talking about the evident R1a-Uralic connection is, because this is The South, not The North, and respect works differently there.
  • Just don’t talk about how Slavs and Balts enter history more than 1,500 years later than Indo-European peoples in Western and Southern Europe, including Iberia, and assume a heroic continuity of Balts and Slavs as pure R1a ‘steppe-like’ peoples dominating over thousands of kms. in the Baltic, Fennoscandia, eastern Europe, and northern Asia for 5,000 years, with multiple Balto-Slavs-over-Balto-Slavs migrations, because these absolute units of Indo-European peoples were a trip and a half. They are the Asterix and Obelix of white Indo-European prehistory.
  • Perhaps in the meantime we can also invent some new glottochronological dialectal scheme that fits the expansion of Sredni Stog/Corded Ware with (Germano-?)Indo-Slavonic separated earlier than any other Late PIE dialect; and Finno-Volgaic later than any other Uralic dialect, in the Middle Ages, with N1c.
balto-slavic-pca
Genetic structure of the Balto-Slavic populations within a European context according to the three genetic systems, from Kushniarevich et al. (2015). Pure Balto-Slavs from…hmm…yeah this…ancient…region…or people…cluster…Whatever, very very steppe-like peoples, the True Indo-Europeans™, so close to Yamna…almost as close as Finno-Ugrians.

To sum up: Iberia, Italy, France, the British Isles, central Europe, the Balkans, the Aegean, or Anatolia, all these territories can have a complex history of periodic admixture and language replacement everywhere, but some peoples appearing later than all others in the historical record (viz. Basques or Slavs) apparently cannot, because that would be shameful for their national or ethnic myths, and these should be respected.

Ignorance of the own past as a blank canvas to be filled in with stupid ethnolinguistic continuity, turned into something valuable that should not be challenged. Ethnonationalist-like reasoning proper of the 19th century. How can our times be called ‘modern’ when this kind of magical thinking is still prevalent, even among supposedly well-educated people?

Related

Iberia: East Bell Beakers spread Indo-European languages; Celts expanded later

iberia-migrations-celts

New paper (behind paywall), The genomic history of the Iberian Peninsula over the past 8000 years, by Olalde et al. Science (2019).

NOTE. Access to article from Reich Lab: main paper and supplementary materials.

Abstract:

We assembled genome-wide data from 271 ancient Iberians, of whom 176 are from the largely unsampled period after 2000 BCE, thereby providing a high-resolution time transect of the Iberian Peninsula. We document high genetic substructure between northwestern and southeastern hunter-gatherers before the spread of farming. We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non-Indo-European–speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia. Additionally, we document how, beginning at least in the Roman period, the ancestry of the peninsula was transformed by gene flow from North Africa and the eastern Mediterranean.

Interesting excerpts:

From the Bronze Age (~2200–900 BCE), we increase the available dataset (6, 7, 17) from 7 to 60 individuals and show how ancestry from the Pontic-Caspian steppe (Steppe ancestry) appeared throughout Iberia in this period (Fig. 1, C and D), albeit with less impact in the south (table S13). The earliest evidence is in 14 individuals dated to ~2500–2000 BCE who coexisted with local people without Steppe ancestry (Fig. 2B). These groups lived in close proximity and admixed to form the Bronze Age population after 2000 BCE with ~40% ancestry from incoming groups (Fig. 2B and fig. S6).

Y-chromosome turnover was even more pronounced (Fig. 2B), as the lineages common in Copper Age Iberia (I2, G2, and H) were almost completely replaced by one lineage, R1b-M269. These patterns point to a higher contribution of incoming males than females, also supported by a lower proportion of nonlocal ancestry on the X-chromosome (table S14 and fig. S7), a paradigm that can be exemplified by a Bronze Age tomb from Castillejo del Bonete containing a male with Steppe ancestry and a female with ancestry similar to Copper Age Iberians.

iberian-adna

For the Iron Age, we document a consistent trend of increased ancestry related to Northern and Central European populations with respect to the preceding Bronze Age (Figs. 1, C and D, and 2B). The increase was 10 to 19% (95% confidence intervals given here and in the percentages that follow) in 15 individuals along the Mediterranean coast where non-Indo-European Iberian languages were spoken; 11 to 31% in two individuals at the Tartessian site of La Angorrilla in the southwest with uncertain language attribution; and 28 to 43% in three individuals at La Hoya in the north where Indo-European Celtiberian languages were likely spoken (fig. S6 and tables S11 and S12).

This trend documents gene flow into Iberia during the Late Bronze Age or Early Iron Age, possibly associated with the introduction of the Urnfield tradition (18). Unlike in Central or Northern Europe, where Steppe ancestry likely marked the introduction of Indo-European languages (12), our results indicate that, in Iberia, increases in Steppe ancestry were not always accompanied by switches to Indo-European languages.

I think it is obvious they are extrapolating the traditional (not that well-known) linguistic picture of Iberia during the Iron Age, believing in continuity of that picture (especially non-Indo-European languages) during the Urnfield period and earlier.

What this data shows is, as expected, the arrival of Celtic languages in Iberia after Bell Beakers and, by extension, in the rest of western Europe. Somewhat surprisingly, this may have happened during the Urnfield period, and not during the La Tène period.

Also important are the precise subclades:

We thus detect three Bronze Age males who belonged to DF27 (154, 155), confirming its presence in Bronze Age Iberia. The other Iberian Bronze Age males could belong to DF27 as well, but the extremely low recovery rate of this SNP in our dataset prevented us to study its true distribution. All the Iberian Bronze Age males with overlapping sequences at R1b-L21 were negative for this mutation. Therefore, we can rule out Britain as a plausible proximate origin since contemporaneous British males are derived for the L21 subtype.


New open access paper Survival of Late Pleistocene Hunter-Gatherer Ancestry in the Iberian Peninsula, by Villalba-Mouco et al. Cell (2019):

BAL0051 could be assigned to haplogroup I1, while BAL003 carries the C1a1a haplogroup. To the limits of our typing resolution, EN/MN individuals CHA001, CHA003, ELT002 and ELT006 share haplogroup I2a1b, which was also reported for Loschbour [73] and Motala HG [13], and other LN and Chalcolithic individuals from Iberia [7, 9], as well as Neolithic Scotland, France, England [9], and Lithuania [14]. Both C1 and I1/ I2 are considered typical European HG lineages prior to the arrival of farming. Interestingly, CHA002 was assigned to haplogroup R1b-M343, which together with an EN individual from Cova de Els Trocs (R1b1a) confirms the presence of R1b in Western Europe prior to the expansion of steppe pastoralists that established a related male lineage in Bronze Age Europe [3, 6, 9, 13, 19]. The geographical vicinity and contemporaneity of these two sites led us to run genomic kinship analysis in order to rule out any first or second degree of relatedness. Early Neolithic individual FUC003 carries the Y haplogroup G2a2a1, commonly found in other EN males from Neolithic Anatolia [13], Starçevo, LBK Hungary [18], Impressa from Croatia and Serbia Neolithic [19] and Czech Neolithic [9], but also in MN Croatia [19] and Chalcolithic Iberia [9].

See also

Cogotas I Bronze Age pottery emulated and expanded Bell Beaker decoration

bronze_age_iberia

Copying from Sherds. Creativity in Bronze Age Pottery in Central Iberia (1800-1150 BC), by Antonio Blanco-González, In: J. Sofaer (ed.): Considering Creativity Creativity, Knowledge and Practice in Bronze Age Europe. Archaeopress (2018), Oxford: 19-38

Interesting excerpts (emphasis mine):

Several Iberian scholars have referred to stab-and-drag designs in both Bell-Beaker and Bronze Age ceramics (Maluquer de Motes 1956, 180, 196; Fernández-Posse 1982, 137), although these have not always been correctly appraised. In the 1980s it was finally realized that the sherds retrieved at the Boquique Cave should be dated to the Middle-Late Neolithic (4400-3300 BC), and that the same technique was also widely used in the Late Bronze Age (Fernández-Posse 1982, 147-149). Thus, nowadays it is possible to track this technique in inland Iberia at different moments throughout later prehistory (Alday and Moral 2011, 67). The earliest stab-and-drag motifs (Figure 2.2, 1) are, in fact, older than was initially thought (Fernández-Posse 1982); they actually date to the Early Neolithic (5500-4400 BC), contemporary to the Mediterranean Cardial impressed wares (Alday 2009, 135-137). There are also a few sporadic examples of stab-and-drag motifs among Bell-Beaker pottery (2600-2000 BC), such as the Ciempozuelos-style bowl from Las Carolinas (Madrid) (Figure 2.2, 2a) featuring so-called ‘symbolic’ schematic stags drawn by using this technique (Blasco and Baena 1996, 431, Lám. II; Garrido Pena 2000, 108). It is also possible to recognize this technique in a large Beaker from Molino Sanchón II (Zamora) (Abarquero et al. 2012, 206, fig. 190; Guerra-Doce et al. 2011, 812) (Figure 2.2, 2b) and there are other possible cases (e.g. Montero and Rodríguez 2008, 166, Lám. IX). Finally, the widespread use of this technique occurred in the Late Bronze Age (Figure 2.2, 3a & 3b) from c.1450 BC (e.g. Rodríguez Marcos 2007, 362-364; Abarquero 2005).

Analogies between Bell-Beaker and Bronze Age wares

Several Bell-Beaker styles can be discerned in the Iberian Meseta (e.g. Harrison 1977, 55-67; Garrido Pena 2000; 2014). In this subsection attention will be drawn primarily to the most frequent of these variants, the Ciempozuelos style, although more localised similarities can be recognised between the Beaker impressed-comb style and some early Cogotas I pottery. The Ciempozuelos ware (Delibes 1977; Harrison 1977, 19-20; Blasco 1994; Garrido Pena 2000, 116-126; Rodríguez Marcos 2007, 252-256) was widespread throughout the Meseta between 2600-2000 BC, in the same region subsequently occupied by Cogotas I communities (1800-1150 BC) (Fernández-Posse 1998; Abarquero 2005) (Figure 2.1). There is a wide array of resemblances between both pottery assemblages, a point that has been highlighted since the 1920s (e.g. Almagro Basch 1939, 143-144; Maluquer de Motes 1956, 196; Harrison 1977, 20; Jimeno 1984, 117-118).

iberian-peninsula-cogotas-i-culture
The Iberian Peninsula and the area of the Cogotas I culture (1800-1150 cal BC). Sites mentioned in the text: 1. Molino Sanchón II (Villafáfila, Zamora); 2. La Horra (El Cerro, Burgos); 3. El Mirador cave (Atapuerca, Burgos); 4. Cueva Maja (Cabrejas del Pinar, Soria); 5. Cueva del Asno (Los Rábanos, Soria); 6. Castilviejo de Yuba (Medinaceli, Soria); 7. Majaladares (Borja, Zaragoza); 8. Cova dels Encantats (Serinyá, Girona); 9. Boquique cave (Plasencia, Cáceres); 10. Cerro de la Cabeza (Ávila); 11. Las Cogotas (Cardeñosa, Ávila); 12. Madrid; 13. Las Carolinas (Madrid); 14. La Indiana (Pinto, Madrid); 15. Llanete de los Moros (Montoro, Córdoba); 16. Peñalosa (Baños de la Encina, Jaén): 17. Cuesta del Negro (Purullena, Granada); 18. Gatas (Turre, Almería); 19. Cabezo Redondo (Villena, Alicante)

The key ornamental traits that define the Ciempozuelos style are also reproduced among Cogotas I ware and are the following:

a) Widespread deployment among the early Cogotas I pottery of the more ubiquitous incised motifs in the Ciempozuelos style: herringbones, spikes and reticulates (Garrido Pena 2000, 119-120, fig. 48, themes 6 and 9; Rodríguez Marcos 2012, 155). During the Middle Bronze Age other less frequent themes are also similar to Bell-Beaker decorations, such as incised triangles filled with lines. Late Bronze Age wares feature the so-called ‘pseudo-Kerbschnitt’ (Rodríguez Marcos 2007, 369) which has striking precedents among Ciempozuelos ware (Harrison 1977, 20; Garrido Pena 2000, 120, fig. 48, theme 12) (Figure 2.3, 1a & 1b).

b) The extensive use of internal rim decoration, almost always deploying chevron motifs. This is ‘a Ciempozuelos leitmotiv’ (Harrison 1977, 20) in the Northern Meseta, where between 30% – 50% of all rims exhibit such a feature (Delibes 1977; Garrido Pena 2000, 163). The decoration of internal rims is even more widespread among Cogotas I vessels (Jimeno 1984; Rodríguez Marcos 2012, 158) (Figure 2.3, 1a).

c) White paste rubbed into the geometric decorations (Delibes 1977; Harrison 1977, 20; Jimeno 1984). Maluquer de Motes (1956, 186) in fact regarded excised and stab-and-drag techniques not as decorations per se, but as a way of anchoring encrusted inlays. He also reported that the bulk of rims in Cogotas I vessels exhibit white accretions (Maluquer de Motes 1956, 192) (Figure 2.3).

In addition, several authors agree on the likeness between the Bell-Beaker impressed-comb style and certain Cogotas I local pottery variants corresponding to its earliest phase (1800-1450 BC) (Garrido Pena 2000, 113-116). This is particularly striking for one micro-style from the western Meseta region, whose ceramics feature numerous impressed-comb motives (e.g. Fabián 2012; Rodríguez Marcos 2012, 158).

bell-beaker-cienpozuelos-cogotas-i
1a) Encrusted Beaker carinated bowls with pseudo-excised motifs from La Salmedina (Madrid) (photo: Museo Arqueológico Regional de Madrid) and 1b) from Cuesta de la Reina (Ciempozuelos, Madrid) (photo: Real Academia de la Historia); 2) Late Bronze Age jar featuring checkerboard excised motives with white paste from Pórragos (Bolaños, Valladolid) (photo: Museo de Valladolid).

The relevance of emulated pottery decorations

[1] (…) there are grounds for proffering the view that the key creative mechanism responsible for the resemblances between apparently unrelated pottery assemblages was the emulation of standalone and very apparent decorative traits. It may constitute a good case for horizontal cultural transmission predicated upon iconic resemblances between easily imitated formal traits (Knappett 2010). Instead of spontaneous and autonomous innovations, it is far more compelling to regard these decorative features as interlinked and punctuated ‘way stations along the trails of living beings, moving through a world’ (Ingold and Hallam 2007, 8). No creative act can be regarded as really isolated. Instead it ought to be understood as focusing on the nodes in particular fields of associations (Lohnmann 2010, 216).

[2] Pottery ornamentation in the Cogotas I tradition combined and reinterpreted both local atavistic (e.g. Abarquero 2005, 24-26; Rodríguez Marcos 2007, 357-367) and widespread pan-European ornaments (e.g. Blasco 2001, 225, 2003, 67-68; Abarquero 2012, 98-101). From a semiotic perspective such things transcended large spatio-temporal distances; they were closely associated by iconical shared links in a relational or cognitive space, whereby these entities were co-presented and indirectly recalled and perceived despite being distant (Knappett 2010, 85-86). The locally-rooted biases of these creative quotations can be glimpsed from rare sequences of ceramic productions spanning several generations of potters. For instance, at Majaladares (Borja, Zaragoza) strong analogies arise between Ciempozuelos wares featuring unique decorations in this site and Cogotas I wares from the superimposed layers, exhibiting remarkably similar themes (Harrison 2007, 65-82). Likewise, it is noteworthy that the earliest triangular excisions in Cogotas I wares occurred in the eastern Meseta, where imported Duffaits vessels featuring comparable motifs were circulating from several centuries before.(…)

[3] There is scope for advocating that these pottery decorations cannot be envisaged as a form of irrelevant or mundane aesthetic garnish for the sake of art. Bronze Age potters drew upon a highly meaningful array of esoteric sources and, in so doing, the vessels might have echoed designs betokening genealogical, mythical or parallel worlds, in a kind of dialectical negotiation between self and other (Taussig 1993). The very involvement of ancestors and spiritual forces in making and embellishing a pot is supported by ethnographic evidence (e.g. Crown 2007, 679; Lohnmann 2010, 222) and this also seems plausible in the case of Cogotas I ceramics. These real or imagined beings might be regarded as inspiring sources of creations, whose role is often to legitimize and guarantee the accuracy of the involved knowledge (Lohnmann 2010, 222). In the same vein, the smearing of colored inlays on certain pots ought to be properly understood beyond an aesthetic action of embellishment, as our own rationale prompts us to assume. (…)

[4] Furthermore, this pottery tradition needs to be understood as an effective means of socialization and a key resource in the forging of identities. Decorating certain intricate Cogotas I vessels (Figure 2.2, 3b; Figure 2.4, 3) very likely involved an ostentatious difficulty (Robb and Michelaki 2012, 168; Abarquero 2005, 438) and the proficiency displayed in such tasks may have accrued even moral connotations (Hendon 2010, 146-147). Learning to perform some of the pottery decoration discussed here certainly required complex training processes involving both expert potters and mentored apprentices (Crown 2007; Hosfield 2009, 46). Thus, the stab-and-drag technique demanded time-consuming learning as well as careful and thorough execution (Alday 2009, 11-19). Likewise the selection and processing of particular raw materials – mainly bones – to attain the white inlays involved direct observation and hands-on training (Odriozola et al. 2012, 150). (…)

[5] Finally, the role of the Cogotas I pottery decoration was also deeply rooted in the sphere of social interactions through particular communal practices of exhibition and consumption. The celebration of commensality rituals is very often predicated as a key social practice among these communities (e.g. Harrison 1995, 74; Abarquero 2005, 56; Blanco-González 2014, 453). Potters embodied and replicated non-discursive shared tenets on a routine basis, but by means of these social gatherings and the deployment of such festive services ‘their visual materialisation made them part of the habitus of everybody’ (Chapman and Gaydarska 2007, 182). Bronze Age groups in the Meseta have recently been characterized as scarcely integrated, short-lasting and unstable social units, lacking long-term cultural rules and institutions, restricted to one generation lifespan at the most (Blanco-González 2015). (…)

Intruding East Bell Beakers

As we know from Olalde et al. (2018) and Mathieson et al. (2018), East Bell Beakers of R1b-L23 subclades and steppe ancestry brought North-West Indo-European languages to Europe, marked in Iberia by the first intrusive Y-DNA R1b-P312 subclades, as supported also by Martiniano et al. (2017) and Valdiosera et al. (2018). In fact, the Bronze Age Cogotas I culture shows the first R1b-DF27 subclade found to date (R1b-DF27 is prevalent among modern Iberians).

If we take into account that the earliest Iberian Bell Beakers were I2a, R1b-V88, and G2a, just like previous Chalcolithic and Neolithic Iberians, it cannot get clearer how and when the first Indo-European waves reached Iberia, and thus that the Harrison and Heyd (2007) model of East Bell Beaker expansion was right. Not a single reputable geneticist contests the origin of R1b-L23 subclades in Iberia anymore (see e.g. Heyd, or Lazaridis).

While the Spanish archaeological school will be slow to adapt to genetic finds – since there are many scholars who have supported for years other ways of expansion of the different Bell Beaker motifs, and follow mostly the “pots not people” descriptive Archaeology – , many works like these can be just as well reinterpreted in light of what we already know happened in terms of population movements during this period, and this alone gives a whole new interesting perspective to archaeological finds.


On the previous, non-Indo-European stage of the Iberian Paeninsula, there is also a new paper (behind paywall), showing reasons for inter-regional differences, and thus supporting homogeneity before the arrival of Bell Beakers:

Stable isotope ratio analysis of bone collagen as indicator of different dietary habits and environmental conditions in northeastern Iberia during the 4th and 3rd millennium cal B.C., by Villalba-Mouco et al. Archaeol Anthropol Sci (2018).

isotope-collagen-iberia
Scatter plot of human and fauna bone collagen δ13C and δ15N values from Cova de la Guineu and Cueva de Abauntz according to their location inside Iberia

Interesting excerpts:

The Chalcolithic period is traditionally defined by the emergence of copper elements and associated to the beginning of defensive-style architecture (Esquivel and Navas 2007). This last characteristic only seems to appear clearly in the southeast of the Iberian Peninsula, with the denominated Millares Culture (e.g. García Sanjuán 2013; Valera et al. 2014). In the rest of the Iberian Peninsula, the Neolithic-Chalcolithic transition is scarcely defined. In fact, it is possible that this transition does not even strictly exist and rather results from the evolution of villages present in the most advanced phases of the Neolithic (e.g. Blasco et al. 2007). This continuity is also perceptible in most of the sepulchral caves over time, where radiocarbon dates show a continued use from the 4th to the 3rd millennium cal B.C. (Fernández-Crespo 2016; Utrilla et al. 2015; Villalba-Mouco et al. 2017). Moreover, it is possible to find some copper materials normally associated with burial contexts as prestigious grave goods (Blasco and Ríos 2010), but not as evidence of a massive replacement of commonly used tools such as flint blades, bone industry, polished stones or pottery without singular characteristics from a unique period (Pérez-Romero et al. 2017). (…)

cova-guineu-cueva-abauntz
Scatter plot of human and fauna bone collagen δ13C and δ15N values from Cueva de Abauntz (above) and Cova de la Guineu (below).

The human isotope values from both sites portray a quite homogeneous overall diet among humans. This homogeneous pattern of diet based on C3 terrestrial resources seems to be general along the entire Iberian Peninsula during the Late Neolithic and Chalcolithic (e.g. Alt et al. 2016; Díaz-Zorita 2014; Fernández-Crespo et al. 2016; Fontanals-Coll et al. 2015; García-Borja et al. 2013; López-Costas et al. 2015; McClure et al. 2011; Sarasketa-Gartzia et al. 2017; Villalba- Mouco et al. 2017; Salazar-García 2011; Salazar-García et al. 2013b; Salazar-García 2014; Waterman et al. 2016). The reason of this homogeneity could be the consolidated economy based on agriculture and livestock, together with a higher mobility among the different communities and the increase of trade networks, not only in prestigious objects (Schuhmacher and Banerjee 2012) but also in food products. Isotopic analyses in fauna remains could give us more clues about animal trade, as happens in other chronologies (Salazar- García et al. 2017).

In any case, and even if the dietary interpretation does not vary, it is noteworthy to mention that there are significant differences between δ13C human values from Cova de la Guineu and δ13C human values from Cueva de Abauntz (Mann-Whitney test, p = 1.05× 10−12) (Fig. 6). This observed δ13C differences among humans is also present among herbivores (Mann-Whitney test, p = 0.0004), which define the baseline of each ecosystem. This suggests that the observed human difference between sites should not be attributed to diet, but most possibly to the existence of enough environmental differences to be recorded in the collagen δ13C values along the food web. Plants are very sensitive to different environmental factors (altitude, temperature, luminosity or water availability) and their physiological adaptation to its factors can generate a variation in their isotopic values as happens with C3 and C4 adaptations (O’Leary 1981; Ambrose 1991). This spectrum of values has been used to assess several aspects about past environmental conditions when studying the δ13C and δ15N isotopic values of a species with a fixed diet over time (e.g. Stevens et al. 2008; González-Guarda et al. 2017). Moreover, this gradual δ13C and δ15N variation among different environments is very helpful to discriminate altitudinal movements in herbivores with a high precision method based on serial dentine analysis (Tornero et al. 2016b). In our case, results reflect the influence of environment from at least two areas in Iberia (the Western Prepyrenees and the Northeastern coast of Iberia). These differences demand caution when interpreting human diets from different sites that are not contemporary and/or not in a same area, as it is possible that the environmental influence is responsible for changes otherwise attributed to different subsistence patterns and social structures (Fernández-Crespo and Schulting 2017), as has been demonstrated in neighbouring territories (Herrscher and Bras-Goude 2010; Goude and Fontugne 2016).

Related:

First Iberian R1b-DF27 sample, probably from incoming East Bell Beakers

bronze_age_iberia

I had some more time to read the paper by Valdiosera et al. (2018) and its supplementary material.

One of the main issues since the publication of Olalde et al. (2018) (and its hundreds of Bell Beaker samples) was the lack of a clear Y-DNA R1b-DF27 subclades among East Bell Beaker migrants, which left us wondering when the subclade entered the Iberian Peninsula, since it could have (theoretically) happened from the Chalcolithic to the Iron Age.

My prediction was that this lineage found today widespread among the Iberian population crossed the Pyrenees quite early, during the Chalcolithic, with migrating East Bell Beakers expanding North-West Indo-European dialects, and that it spread slowly afterwards.

The first ancient sample clearly identified as of R1b-DF27 subclade is found in this paper, at the Late Bronze Age site Cueva de los Lagos. Although it is unidentified and has no radiocarbon date, the site as a whole is associated with the Cogotas culture and its Bouquique ceramic decoration.

iberia-y-dna-mtdna
Y-DNA and mtDNA haplogroups, from the paper. Sequencing statistics and contamination rates for newly generated sequence data.

It was found in the northern part of the Cogotas culture territory (which lies mainly between Castille and Aragon, in North-Central Spain), shows evident steppe admixture, and it has become obvious with the latest papers (including this one) that R1b-M269 lineages intruded south of the Pyrenees associated with East Bell Beaker migrations.

The Proto-Cogotas culture is associated with a Bell Beaker substrate influenced by either El Argar or Atlantic Bronze, and the specific type of ceramics found at this Cogotas culture site are probably from the mid-2nd millennium, which is too early for the Celtic expansion.

iberia-steppe-admixture
Supervised ADMIXTURE results.

Nevertheless, due to the quite likely late date of the sample (in the centuries around 1500 BC), there is still a possibility that incoming R1b-DF27 lineages were not among the early R1b-M269 lineages found in the Iberian Chalcolithic, and were associated with later migrations from Central Europe, potentially linked to the expansion of the Urnfield culture, and thus nearer to an Italo-Celtic community.

bronze-age-tollense
Diachronic map of migrations in Europe ca. 1250-750 BC.

In any of these scenarios, a Pre-Celtic expansion of North-West Indo-European in Iberia (possibly associated with Lusitanian) is still the best explanation for the origin and expansion of (at least some) modern Iberian R1b-DF27 lineages, including those found among the Basque-speaking population.

This implies that the ‘indigenous’ Neolithic lineages of Iberia (like I2 and G2a2) were replaced with subsequent internal gene flows and founder effects, such as those that evidently happened (probably quite recently) among Basques, even though indigenous languages show an obvious continuity.

I would say this is the last nail in the coffin for autochthonous Y-DNA continuity theories for Spain and France (i.e. for the traditional Vasconic-Uralic hypothesis), but we know that data is never enough for any die hard continuist…so let’s just say another nail in the coffin for endless autochthonous continuity theories.

EDIT (18 & 26 MAR 2018): Genetiker has published Y-SNP calls for both R1b samples, showing this one is R1b1a1a2a1a2a-BY15964 (see modern members of this subclade in ytree), and that the other one is R1b1a1a2a~L23.

Related:

Yleaf: software for human Y-chromosomal haplogroup inference from next generation sequencing data

portugal-bronze-age-admixture

Brief communication (behind paywall) Yleaf: software for human Y-chromosomal haplogroup inference from next generation sequencing data, by Arwin Ralf, Diego Montiel González, Kaiyin Zhong, and Manfred Kayser, Mol Biol Evol (2018), msy032.

Abstract

Next generation sequencing (NGS) technologies offer immense possibilities given the large genomic data they simultaneously deliver. The human Y chromosome serves as good example how NGS benefits various applications in evolution, anthropology, genealogy and forensics. Prior to NGS, the Y-chromosome phylogenetic tree consisted of a few hundred branches, based on NGS data it now contains many thousands. The complexity of both, Y tree and NGS data provide challenges for haplogroup assignment. For effective analysis and interpretation of Y-chromosome NGS data, we present Yleaf, a publically available, automated, user-friendly software for high-resolution Y-chromosome haplogroup inference independently of library and sequencing methods.

Here is a link to the software Yleaf’s website, from the Department of Genetic Identification, at the University of Erasmus Medical Center.

yleaf-martiniano
Summary of NGS datasets used for automated NRY haplogrouping with Yleaf

Excerpt:

In the time of NGS (or massively parallel sequencing, MPS), the amount of genomic data produced and made publically available is rapidly expanding, providing valuable resources for many areas of research and applications. Due to its haploid nature and male-specific inheritance, the non-recombining part of the human Y-chromosome (NRY) is highly suitable for phylogenetic studies and for addressing questions in evolution, anthropology, population history, genealogy and forensics (Jobling & Tyler-Smith, 2017). Over recent years, NGS data allowed the phylogenetic NRY tree to dramatically increase in size and complexity (Hallast et al. 2014; Poznik et al. 2016). The two most comprehensive tree versions ISOGG (http://www.isogg.org/tree) and Yfull (https://www.yfull.com/tree) currently contain thousands of branches. However, the complexity of both, Y tree and NGS data provide immense challenges for NRY haplogroup assignment, which reflects a key element in many NRY applications. Here we introduce Yleaf, a Phyton-based, easy-to-use, publically-available software tool for effective NRY single nucleotide polymorphism (SNP) calling and subsequent NRY haplogroup inference from NGS data. By comparative whole genome data analysis, we demonstrate high concordance of Yleaf in NRY-SNP calling compared to well-established tools such as SAMtools/BCFtools (Li et al. 2009), and GATK (McKenna, et al. 2010) as well as improved performance of Yleaf in NRY haplogroup assignment relative to previously developed tools such as clean_tree (Ralf et al. 2015), AMY-tree (Van Geystelen et al. 2015), and yHaplo (Poznik, 2016).

Yleaf allows analyzing NRY sequence data from many types of NGS libraries i.e., whole genomes, whole exomes, large genomic regions, and large numbers of targeted amplicons. Several modifications relative to our previously developed clean_tree tool (Ralf et al. 2015) were implemented to optimize the performance especially relevant for extremely large NGS datasets such as whole genomes. For instance, Yleaf extracts the Y-chromosomal reads prior to further processing and uses multi-threading, a batch option is included too. Importantly, Yleaf provides drastically increased haplogroup resolution i.e., from Downloaded from 530 positions defining 432 NRY haplogroups with clean_tree (Ralf et al. 2015) to over 41,000 positions defining 5353 haplogroups with Yleaf. For a detailed method description see the supplementary material.

Featured image: From Martiniano et al. (2017).

Related: