North-West Indo-Europeans of Iberian Beaker descent and haplogroup R1b-P312

iron-age-early-mediterranean

The recent data on ancient DNA from Iberia published by Olalde et al. (2019) was interesting for many different reasons, but I still have the impression that the authors – and consequently many readers – focused on not-so-relevant information about more recent population movements, or even highlighted the least interesting details related to historical events.

I have already written about the relevance of its findings for the Indo-European question in an initial assessment, then in a more detailed post about its consequences, then about the arrival of Celtic languages with hg. R1b-M167, and later in combination with the latest hydrotoponymic research.

This post is thus a summary of its findings with the help of natural neighbour interpolation maps of the reported Germany_Beaker and France_Beaker ancestry for individual samples. Even though maps are not necessary, visualizing geographically the available data facilitates a direct comprehension of the most relevant information. What I considered key points of the paper are highlighted in bold, and enumerated.

NOTE. To get “more natural” maps, extrapolation for the whole Iberian Peninsula is obtained by interpolation through the use of external data from the British Isles, Central Europe, and Africa. This is obviously not ideal, but – lacking data from the corners of the Iberian Peninsula – this method gives a homogeneous look to all maps. Only data in direct line between labelled samples in each map is truly interpolated for the Iberian Peninsula, while the rest would work e.g. for a wider (and more simplistic) map of European Bronze Age ancestry components.

Chalcolithic

iberia-chalcolithic
Iberian Chalcolithic groups and expansion of the Proto-Beaker package. See full map.

The Proto-Beaker package may or may not have expanded into Central Europe with typical Iberia_Chalcolithic ancestry. A priori, it seems a rather cultural diffusion of traits stemming from west Iberia roughly ca. 2800 BC.

iberia-y-dna-map-chalcolithic
Map of Y-DNA haplogroups among Iberia Chalcolithic samples. See full map.

The situation during the Chalcolithic is only relevant for the Indo-European question insofar as it shows a homogeneous Iberia_Chalcolithic-like ancestry with typical Y-chromosome (and mtDNA) haplogroups of the Iberian Neolithic dominating over the whole Peninsula until about 2500 BC. This might represent an original Basque-Iberian community.

iberia-mtdna-map-chalcolithic
Map of mtDNA haplogroups among Iberia Chalcolithic samples. See full map.

Bell Beaker period

iberia-bell-beaker-period
Iberian Bell Beaker groups and potential routes of expansion. See full map.

The expansion of the Bell Beaker folk brought about a cultural and genetic change in all Europe, to the point where it has been rightfully considered by Mallory (2013) – the last one among many others before him – the vector of expansion of North-West Indo-European languages. Olalde et al. (2019) proved two main points in this regard, which were already hinted in Olalde et al. (2018):

(1) East Bell Beakers brought hg. R1b-L23 and Yamnaya ancestry to Iberia, ergo the Bell Beaker phenomenon was not a (mere) local development in Iberia, but involved the expansion of peoples tracing their ancestry to the Yamnaya culture who eventually replaced a great part of the local population.

iberia-ancestry-bell-beaker-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Bell Beaker period (ca. 2600-2250 BC). See full map.

(2) Classical Bell Beakers have their closest source population in Germany Beakers, and they reject an origin close to Rhine Beakers (i.e. Beakers from the British Isles, the Netherlands, or northern France), ergo the Single Grave culture was not the origin of the Bell Beaker culture, either (see here).

iberia-y-dna-map-bell-beaker-period
Map of Y-DNA haplogroups among Iberian Bell Beaker samples. See full map.
iberia-mtdna-map-bell-beaker-period
Map of mtDNA haplogroups among Iberian Bell Beaker samples. See full map.

Early Bronze Age

iberia-early-bronze-age
Iberian Early Bronze Age groups and likely population and culture expansions. See full map.

Interestingly, the European Early Bronze Age in Iberia is still a period of adjustments before reaching the final equilibrium. Unlike the situation in the British Isles, where Bell Beakers brought about a swift population replacement, Iberia shows – like the Nordic Late Neolithic period – centuries of genomic balancing between Indo-European- and non-Indo-European-speaking peoples, as could be suggested by hydrotoponymic research alone.

(3) Palaeo-Indo-European-speaking Old Europeans occupied first the whole Iberian Peninsula, before the potential expansion of one or more non-Indo-European-speaking groups, which confirms the known relative chronology of hydrotoponymic layers of Iberia.

iberia-ancestry-early-bronze-age-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Early Bronze Age period (ca. 2250-1750 BC). See full map.

This balancing is seen in terms of Germany_Beaker vs. Iberia_Chalcolithic ancestry, but also in terms of Y-chromosome haplogroups, with the most interesting late developments happening in southern Iberia, around the territory where El Argar eventually emerged in radical opposition to the Bell Beaker culture.

iberia-y-dna-map-early-bronze-age
Map of Y-DNA haplogroups among Iberia Early Bronze Age samples. See full map.

(4) Bell Beakers and descendants expanded under male-driven migrations, proper of the Indo-European patrilineal tradition, seen in Yamnaya and even earlier in Khvalynsk:

We obtained lower proportions of ancestry related to Germany_Beaker on the X-chromosome than on the autosomes (Table S14), although the Z-score for the differences between the estimates is 2.64, likely due to the large standard error associated to the mixture proportions in the X-chromosome.

germany-beaker-x-chromosome

iberia-mtdna-map-early-bronze-age
Map of mtDNA haplogroups among Iberia Early Bronze Age samples. See full map.

Regarding the PCA, Iberia Bronze Age samples occupy an intermediate cluster between Iberia Chalcolithic and Bell Beakers of steppe ancestry, with Yamnaya-rich samples from the north (Asturias, Burgos) representing the likely source Old European population whose languages survived well into the Roman Iron Age:

iberia-pca-bronze-age
PCA of ancient European samples. Marked and labelled are Bronze Age groups and relevant samples. See full image.

Middle Bronze Age

iberia-middle-bronze-age
Iberian Middle Bronze Age groups and likely population and culture expansions. See full map.

During the Middle Bronze Age, the equilibrium reached earlier is reversed, with a (likely non-Indo-European-speaking) Argaric sphere of influence expanding to the west and north featuring Iberia Chalcolithic and lesser amount of Germany_Beaker ancestry, present now in the whole Peninsula, although in varying degrees.

iberia-ancestry-middle-bronze-age-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Middle Bronze Age period (ca. 1750-1250 BC). See full map.

All Iberian groups were probably already under a bottleneck of R1b-DF27 lineages, although it is likely that specific subclades differed among regions:

iberia-y-dna-map-middle-bronze-age
Map of Y-DNA haplogroups among Iberia Middle Bronze Age samples. See full map.
iberia-mtdna-map-middle-bronze-age
Map of mtDNA haplogroups among Iberia Middle Bronze Age samples. See full map.

Late Bronze Age

iberia-late-bronze-age
Iberian Late Bronze Age groups and likely population and culture expansions. See full map.

The Late Bronze Age represents the arrival of the Urnfield culture, which probably expanded with Celtic-speaking peoples. A Late Bronze Age transect before their genetic impact still shows a prevalent Germany_Beaker-like Steppe ancestry, probably peaking in north/west Iberia:

iberia-ancestry-late-bronze-age-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Late Bronze Age period (ca. 1250-750 BC). See full map.

(5) Galaico-Lusitanians were descendants of Iberian Beakers of Germany_Beaker ancestry and hg. R1b-M269. Autosomal data of samples I7688 and I7687, of the Final Bronze (end of the reported 1200-700 BC period for the samples), from Gruta do Medronhal (Arrifana, Coimbra, Portugal) confirms this.

In the 1940s, human bones, metallic artifacts (n=37) and non-human bones were discovered in the natural cave of Medronhal (Arrifana, Coimbra). All these findings are currently housed in the Department of Life Sciences of the University of Coimbra and are analyzed by a multidisciplinary team. The artifacts suggest a date at the beginning of the 1st millennium BC, which is confirmed by radiocarbon date of a human fibula: 890–780 cal BCE (2650±40 BP, Beta–223996). This natural cave has several rooms and corridors with two entrances. No information is available about the context of the human remains. Nowadays these remains are housed mixed and correspond to a minimum number of 11 individuals, 5 adults and 6 non-adults.

In particular, sample I7687 shows hg. R1b-M269, with no available quality SNPs, positive or negative, under it (see full report). They represent thus another strong support of the North-West Indo-European expansion with Bell Beakers.

iberia-y-dna-map-late-bronze-age
Map of Y-DNA haplogroups among Iberian Late Bronze Age samples. See full map.
iberia-mtdna-map-late-bronze-age
Map of mtDNA haplogroups among Iberian Late Bronze Age samples. See full map.

NOTE. To understand how the region around Coimbra was (Proto-)Lusitanian – and not just Old European in general – until the expansion of the Turduli Oppidani, see any recent paper on Bronze Age expansion of warrior stelae, hydrotoponymy, anthroponymy, or theonymy (see e.g. about Spear-vocabulary).

Iron Age

iberia-iron-age-early
Iberian Pre-Roman Iron Age groups and likely population and culture expansions. See full map.

In a complex period of multiple population movements and language replacements, the temporal transect in Olalde et al. (2019) offers nevertheless relevant clues for the Pre-Roman Iron Age:

(6) The expansion of Celtic languages was associated with the spread of France_Beaker-like ancestry, most likely already with the LBA Urnfield culture, since a Tartessian and a Pre-Iberian samples (both dated ca. 700-500 BC) already show this admixture, in regions which some centuries earlier did not show it. Similarly, a BA sample from Álava ca. 910–840 BC doesn’t show it, and later Celtiberian samples from the same area (ca. 4th c. BC and later) show it, depicting a likely north-east to west/south-west routes of expansion of Celts.

iberia-ancestry-iron-age-france_beaker
Natural neighbor interpolation of France_Beaker ancestry in Iberia during the Pre-Roman Iron Age period (ca. 750-250 BC). See full map.

(7) The distribution of Germany_Beaker ancestry peaked, by the Iron Age, among Old Europeans from west Iberia, including Galaico-Lusitanians and probably also Astures and Cantabri, in line with what was expected before genetic research:

iberia-ancestry-iron-age-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Pre-Roman Iron Age period (ca. 750-250 BC). See full map.

A probably more precise picture of the Final Bronze – Early Iron Age transition is obtained by including the Final Bronze samples I2469 from El Sotillo, Álava (ca. 910-875 BC) as Celtic ancestry buffer to the west, and the sample I3315 from Menorca (ca. 904-861 BC), lacking more recent ones from intermediate regions:

iberia-ancestry-ia-germany_beaker
Natural neighbor interpolation of Germany_Beaker ancestry in Iberia during the Final Bronze Age – Early Iron Age transition. See full map.
iberia-ancestry-ia-france_beaker
Natural neighbor interpolation of France_Beaker ancestry in Iberia during the Final Bronze Age – Early Iron Age transition. See full map.

In terms of Y-DNA and mtDNA haplogroups, the situation is difficult to evaluate without more samples and more reported subclades:

iberia-y-dna-map-iron-age
Map of Y-DNA haplogroups among Iberian Iron Age samples. See full map.
iberia-mtdna-map-iron-age
Map of mtDNA haplogroups among Iberian Iron Age samples. See full map.

In the PCA, Proto-Lusitanian samples occupy an intermediate cluster between Iberian Bronze Age and Bronze Age North (see above), including the Final Bronze sample from Álava, while Celtic-speaking peoples (including Pre-Iberians and Iberians of Celtic descent from north-east Iberia) show a similar position – albeit evidently unrelated – due to their more recent admixture between Iberian Bronze Age and Urnfield/Hallstatt from Central Europe:

iberia-pca-iron-age
PCA of ancient European samples. Marked and labelled are Iron Age groups and relevant samples. See full image.

(8) Iberian-speaking peoples in north-east Iberia represent a recent expansion of the language from the south, possibly accompanied by an increase in Iberia_Chalcolithic/Germany_Beaker admixture from east/south-east Iberia.

(9) Modern Basques represent a recent isolation + Y-DNA bottlenecks after the Roman Iron Age population movements, probably from Aquitanians migrating south of the Pyrenees, admixing with local peoples, and later becoming isolated during the Early Middle Ages and thereafter:

[Modern Basques] overlap genetically with Iron Age populations showing substantial levels of Steppe ancestry.

Assuming that France_Beaker ancestry is associated with the Urnfield culture (spreading with Celtic-speaking peoples), Vasconic speakers were possibly represented by some population – most likely from France – whose ancestry is close to Rhine Beakers (see here).

Alternatively, a Vasconic language could have survived in some France/Iberia_Chalcolithic-like population that got isolated north of the Pyrenees close to the Atlantic Façade during the Bronze Age, and who later admixed with Celtic-speaking peoples south of the Pyrenees, such as the Vascones, to the point where their true ancestry got diluted.

In any case, the clear Celtic Steppe-like admixture of modern Basques supports for the time being their recent arrival to Aquitaine before the proto-historical period, which is in line with hydrotoponymic research.

Conclusion

The most interesting aspects to discuss after the publication of Olalde et al. (2019) would have been thus the nature of controversial Palaeohispanic peoples for which there is not much linguistic data, such as:

  • the Astures and the Cantabri, usually considered Pre-Celtic Indo-European (see here);
  • the Vaccaei, usually considered Celtic;
  • the Vettones, traditionally viewed as sharing the same language as Lusitanians due to their apparent shared hydrotoponymic, anthroponymic, and/or theonymic layers, but today mostly viewed as having undergone Celticization and helped the westward expansion of Celtic languages (and archaeologically clearly divided from Old European hostile neighbours to the west by their characteristic verracos);
  • the Pellendones or the Carpetani, who were once considered Pre-Celtic Indo-Europeans, too;
  • the nature of Tartessian as Indo-European, or maybe even as “Celtic”, as defended by Koch;
  • or the potential remote connection of Basque and Iberian languages in a common trunk featuring Iberian/France_Chalcolithic ancestry (also including Palaeo-Sardo).
pre-roman-palaeohispanic-languages-peoples-iberia-300bc
Pre-Roman Palaeohispanic peoples ca. 300 BC. See full map. Image modified from the version at Wikipedia, a good example of how to disseminate the wrong ideas about Palaeohispanic languages.

Despite these interesting questions still open for discussion, the paper remarked something already known for a long time: that modern Basques had steppe ancestry and Y-DNA proper of the Yamnaya 5,000 years ago, and that Bell Beakers had brought this steppe ancestry and R1b-P312 lineages to Iberia. This common Basque-centric interpretation of Iberian prehistory is the consequence of a 19th-century tradition of obsessively imagining Vasconic-speaking peoples in their medieval territories extrapolated to Cro-Magnons and Atapuerca (no, really), inhabiting undisturbed for millennia a large territory encompassing the whole Iberia and France, “reduced” or “broken” only with the arrival of Celts just before the Roman conquests. A recursive idea of “linguistic autochthony” and “genetic purity” of the peoples of Iberia that has never had any scientific basis.

Similarly, this paper offered the Nth proof already in population genomics that traditional nativist claims for the origin of the Bell Beaker folk in Western Europe were wrong, both southern (nativist Iberian origin) and northern European (nativist Lower Rhine origin). Both options could be easily rejected with phylogeography since 2015, they were then rejected in Olalde et al. and Mathieson et al (2017), then again with the update of many samples in Olalde et al. (2018) and Mathieson et al (2018), and it has most clearly been rejected recently with data from Wang et al. (2018) and its Yamnaya Hungary samples. Findings from Olalde et al. (2019) are just another nail to coffins that should have been well buried by now.

Even David Anthony didn’t have any doubt in his latest model (2017) about the Carpathian Basin origin of North-West Indo-Europeans (see here), and his latest update to the Proto-Indo-European homeland question (2019) shows that he is convinced now about R1b bottlenecks and proper Pre-Yamnaya ancestry stemming from a time well before the Bell Beaker expansion. This won’t be the last setback to supporters of zombie theories: like the hypotheses of an Anatolian, Armenian, or OIT origin of the PIE homeland, other mythical ideas are so entrenched in nationalist and/or nativist tradition that many supporters will no doubt prefer them to die hard, under the most numerous and shameful rejections of endlessly remade reactionary models.

Related

Modern Sardinians show elevated Neolithic farmer ancestry shared with Basques

sardinia-europe-relation

New paper (behind paywall), Genomic history of the Sardinian population, by Chiang et al. Nature Genetics (2018), previously published as a preprint at bioRxiv (2016).

#EDIT (18 Sep 2018): Link to read paper for free shared by the main author.

Interesting excerpts (emphasis mine):

Our analysis of divergence times suggests the population lineage ancestral to modern-day Sardinia was effectively isolated from the mainland European populations ~140–250 generations ago, corresponding to ~4,300–7,000 years ago assuming a generation time of 30 years and a mutation rate of 1.25 × 10−8 per basepair per generation. (…) in terms of relative values, the divergence time between Northern and Southern Europeans is much more recent than either is to Sardinia, signaling the relative isolation of Sardinia from mainland Europe.

We documented fine-scale variation in the ancient population ancestry proportions across the island. The most remote and interior areas of Sardinia—the Gennargentu massif covering the central and eastern regions, including the present-day province of Ogliastra— are thought to have been the least exposed to contact with outside populations. We found that pre-Neolithic hunter-gatherer and Neolithic farmer ancestries are enriched in this region of isolation. Under the premise that Ogliastra has been more buffered from recent immigration to the island, one interpretation of the result is that the early populations of Sardinia were an admixture of the two ancestries, rather than the pre-Neolithic ancestry arriving via later migrations from the mainland. Such admixture could have occurred principally on the island or on the mainland before the hypothesized Neolithic era influx to the island. Under the alternative premise that Ogliastra is simply a highly isolated region that has differentiated within Sardinia due to genetic drift, the result would be interpreted as genetic drift leading to a structured pattern of pre-Neolithic ancestry across the island, in an overall background of high Neolithic ancestry.

sardinia-pca
PCA results of merged Sardinian whole-genome sequences and the HGDP Sardinians. See below for a map of the corresponding regions.

We found Sardinians show a signal of shared ancestry with the Basque in terms of the outgroup f3 shared-drift statistics. This is consistent with long-held arguments of a connection between the two populations, including claims of Basque-like, non-Indo-European words among Sardinian placenames. More recently, the Basque have been shown to be enriched for Neolithic farmer ancestry and Indo-European languages have been associated with steppe population expansions in the post-Neolithic Bronze Age. These results support a model in which Sardinians and the Basque may both retain a legacy of pre-Indo-European Neolithic ancestry. To be cautious, while it seems unlikely, we cannot exclude that the genetic similarity between the Basque and Sardinians is due to an unsampled pre-Neolithic population that has affinities with the Neolithic representatives analyzed here.

density-nuraghi-sardinia-genetics
Left: Geographical map of Sardinia. The provincial boundaries are given as black lines. The provinces are abbreviated as Cag (Cagliari), Cmp (Campidano), Car (Carbonia), Ori (Oristano), Sas (Sassari), Olb (Olbia-tempio), Nuo (Nuoro), and Ogl (Ogliastra). For sampled villages within Ogliastra, the names and abbreviations are indicated in the colored boxes. The color corresponds to the color used in the PCA plot (Fig. 2a). The Gennargentu region referred to in the main text is the mountainous area shown in brown that is centered in western Ogliastra and southeastern Nuoro.
Right: Density of Nuraghi in Sardinia, from Wikipedia.

While we can confirm that Sardinians principally have Neolithic ancestry on the autosomes, the high frequency of two Y-chromosome haplogroups (I2a1a1 at ~39% and R1b1a2 at ~18%) that are not typically affiliated with Neolithic ancestry is one challenge to this model. Whether these haplogroups rose in frequency due to extensive genetic drift and/or reflect sex-biased demographic processes has been an open question. Our analysis of X chromosome versus autosome diversity suggests a smaller effective size for males, which can arise due to multiple processes, including polygyny, patrilineal inheritance rules, or transmission of reproductive success. We also find that the genetic ancestry enriched in Sardinia is more prevalent on the X chromosome than the autosome, suggesting that male lineages may more rapidly trace back to the mainland. Considering that the R1b1a2 haplogroup may be associated with post-Neolithic steppe ancestry expansions in Europe, and the recent timeframe when the R1b1a2 lineages expanded in Sardinia, the patterns raise the possibility of recent male-biased steppe ancestry migration to Sardinia, as has been reported among mainland Europeans at large (though see Lazaridis and Reich and Goldberg et al.). Such a recent influx is difficult to square with the overall divergence of Sardinian populations observed here.

sardinian-admixture
Mixture proportions of the three-component ancestries among Sardinian populations. Using a method first presented in Haak et al. (Nature 522, 207–211, 2015), we computed unbiased estimates of mixture proportions without a parameterized model of relationships between the test populations and the outgroup populations based on f4 statistics. The three-component ancestries were represented by early Neolithic individuals from the LBK culture (LBK_EN), pre-Neolithic huntergatherers (Loschbour), and Bronze Age steppe pastoralists (Yamnaya). See Supplementary Table 5 for standard error estimates computed using a block jackknife.

Once again, haplogroup R1b1a2 (M269), and only R1b1a2, related to male-biased, steppe-related Indo-European migrations…just sayin’.

Interestingly, haplogroup I2a1a1 is actually found among northern Iberians during the Neolithic and Chalcolithic, and is therefore associated with Neolithic ancestry in Iberia, too, and consequently – unless there is a big surprise hidden somewhere – with the ancestry found today among Basques.

NOTE. In fact, the increase in Neolithic ancestry found in south-west Ireland with expanding Bell Beakers (likely Proto-Beakers), coupled with the finding of I2a subclades in Megalithic cultures of western Europe, would support this replacement after the Cardial and Epi-Cardial expansions, which were initially associated with G2a lineages.

I am not convinced about a survival of Palaeo-Sardo after the Bell Beaker expansion, though, since there is no clear-cut cultural divide (and posterior continuity) of pre-Beaker archaeological cultures after the arrival of Bell Beakers in the island that could be identified with the survival of Neolithic languages.

We may have to wait for ancient DNA to show a potential expansion of Neolithic ancestry from the west, maybe associated with the emergence of the Nuragic civilization (potentially linked with contemporaneous Megalithic cultures in Corsica and in the Balearic Islands, and thus with an Iberian rather than a Basque stock), although this is quite speculative at this moment in linguistic, archaeological, and genetic terms.

Nevertheless, it seems that the association of a Basque-Iberian language with the Neolithic expansion from Anatolia (see Villar’s latest book on the subject) is somehow strengthened by this paper. However, it is unclear when, how, and where expanding G2a subclades were replaced by native I2 lineages.

Related

The Proto-Indo-European – Euskarian hypothesis

palaeolithic

Another short communication by Juliette Blevins has just been posted, A single sibilant in Proto-Basque: *s, *Rs, *sT and the phonetic basis of the sibilant split:

Blevins (to appear) presents a new reconstruction of Proto-Basque, the mother of Basque and Aquitanian, based on standard methods in historical linguistics: the comparative method and the method of internal reconstruction. Where all previous reconstructions of Proto-Basque assume a contrast between two sibilants, *s, a voiceless apical sibilant, and *z a voiceless laminal sibilant (Martinet 1955; Michelena 1977; Lakarra 1995; Trask 1997), this proposal is unique in positing only a single sibilant *s. Under this account, all instances of Common Basque /z/ are derived from *s. More specifically, in syllable coda, *Rs > *Rz (R a sonorant) while in the syllable onset, *sT > *zT (T an oral stop). The true split of *s into /s/ vs. /z/ occurs when clusters like *Rz or *zT are further simplified to /z/.

In this talk, internal evidence for a single sibilant, *s, in Proto-Basque is presented, and sound changes underlying the sibilant split are examined within the context of Evolutionary Phonology (Blevins 2004, 2006, 2015, 2017). Similar sound changes are identified in other languages with similar cluster types (e.g. Kümmel 2007:232), and the phonetic basis of the sibilant split is informed by recent studies of sibilant retraction (e.g. Stevens and Harrington 2016; Stuart-Smith et al. 2018).

Blevins, already known for her previous work on the Basque language, was known internationally for her recent controversial proposal of a genetic relationship between Proto-Indo-European and Basque. Apparently, a book with her full model, Advances in Proto-Basque Reconstruction with evidence for the Proto-Indo-European-Euskarian Hypothesis, will be published by Routledge soon.

I was never convinced, not just about a genetic connection, but about the very possibility of discovering it if there was any, mainly because such a link would be quite old, and Basque is known to have been greatly influenced by surrounding IE prestige languages for millennia until it was first attested in the 16th century. Internal reconstruction can only avail a gross reconstruction of few aspects up to a certain point in time, probably not very far beyond the Pre-Roman period, and that only thanks to the available Aquitanian inscriptions.

There are indeed certain known migrations that could be linked with a pan-European population movement, the most likely one for this hypothesis being the Villabruna cluster (the Villabruna sample itself being of haplogroup R1b pre-P297), and especially the expansion of R1b-V88 lineages, found widespread in Europe from west to east, from Mesolithic Iberia to Khvalynsk.

This haplogroup is also found in Sardinia, which may be connected to the expansion of V88 subclades (which I have speculatively proposed could be linked to Afro-Asiatic) into Africa through Italy and the Green Sahara; although it could also be linked to a speculative Vasconic-Iberian – Palaeo-Sardo group.

Without knowing the exact Pre-Proto-Indo-European stage at which Blevins would place the Basque separation, it is difficult to know how it could fit within any macro-language proposal – and thus potential ancestral population expansion.

If you are interested in this hypothesis, I suggest Koch’s controversial paper of 2013 Is Basque an Indo-European Language? (PDF), appeared in JIES 41 (1 & 2)….And of course the many papers rejecting it in the same volume. You also have Forni’s writings supporting this association.

Seeing how many Basque nationalists (obviously obsessed with racial purity) are still rooting for an autochthonous Palaeolithic origin of R1b lineages (especially P312) linked with the Basque language and dat huge Vasconic Western Europe; and now, after Olalde & Mathieson 2018, how some are also suggesting a Neolithic link of R1b with the Neolithic expansion and Sardinians, for lack of further modern genetic differences with other Western Europeans… I wonder how a lot of people inclined to believe this nonsense today, and mentally linking Vasconic with haplogroup R1b, will be paradoxically necessarily tied precisely to this kind of macro-family proposals in the future.

Related: