More Celts of hg. R1b, more Afanasievo ancestry, more maps

iron-age-early-celtic-expansion

Interesting recent developments:

Celts and hg. R1b

Gauls

Recent paper (behind paywall) Multi-scale archaeogenetic study of two French Iron Age communities: From internal social- to broad-scale population dynamics, by Fischer et al. J Archaeol Sci (2019).

In it, Fischer and colleagues update their previous data for the Y-DNA of Gauls from the Urville-Nacqueville necropolis, Normandy (ca. 300-100 BC), with 8 samples of hg. R, at least 5 of them R1b. They also report new data from the Gallic cemetery at Gurgy ‘Les Noisats’, Southern Paris Basin (ca. 120-80 BC), with 19 samples of hg. R, at least 13 of them R1b.

In both cases, it is likely that both communities belonged (each) to the same paternal lineages, hence the patrilocal residence rules and patrilineality described for Gallic groups, also supported by the different maternal gene pools.

The interesting data would be whether these individuals were of hg. R1b-L21, hence mainly local lineages later replaced or displaced to the west, or – a priori much more likely – of some R1b-U152 and/or R1b-DF27 subclades from Central Europe that became less and less prevalent as Celts expanded into more isolated regions south of the Pyrenees and into the British Isles. Such information is lacking in the paper, probably due to the poor coverage of the samples.

early-iron-age-europe-y-dna
Y-DNA haplogroups in Europe during the Early Iron Age. See full map.

Other Celts

As for early Celts, we already have:

Celtiberians from the Basque Country (one of hg. I2a) and likely Celtic genetic influence in north-east Iberia (all R1b), where Iberian languages spread later, showing that Celts expanded from some place in Central Europe, probably already with the Urnfield culture (ca. 1300 BC on).

Two Hallstatt samples from Bylany, Bohemia (ca. 836-780 BC), by Damgaard et al. Nature (2018), one of them of hg. R1b-U152.

mitterkirchen-grab-hu-i-8-hallstatt
Photo and diagram of burial HÜ-I/8, Mitterkirchen, Oberösterreich, Leskovar 1998.

Another Hallstatt HaC/D1 sample from Mittelkirchen, Austria (ca. 850-650/600), by Kiesslich et al. (2012), with predicted hg. G2a (see Athey’s haplogroup prediction).

One sample of early La Tène culture A from Putzenfeld am Dürrnberg, Hallein, Austria (ca 450–380 BC), by Kiesslich et al. (2012), with predicted hg. R1b (see Athey’s haplogroup prediction).

NOTE. For potential unreliability of haplogroup prediction with Whit Atheys’ haplogroup predictor, see e.g. Zhang et al. (2017).

kelten-dna-putzenfeld-duerrnberg-grab-376
Photo and diagram of Burial 376, Putzenfeld, Dürrnberg bei Hallein, Moser 2007.

Three Britons from Hinxton, South Cambridgeshire (ca. 170 BC – AD 80) from Schiffels et al. (2016), two of them of local hg. R1b-S461.

Indirectly, data of Vikings by Margaryan et al. (2019) from the British Isles and beyond show hg. R1b associated with modern British-like ancestry, also linked to early “Picts”, hence likely associated with Britons even after the Anglo-Saxon settlement. Supporting both (1) my recent prediction of hg. R1b-M167 expanding with Celts and (2) the reason for its presence among modern Scandinavians, is the finding of the first ancient sample of this subclade (VK166) among the Vikings of St John’s College Oxford, associated with the ‘St Brice’s Day Massacre’ (see Margaryan et al. 2019 supplementary materials).

The R1b-M167 sample shows 23.5% British-like ancestry, hence autosomally closer to other local samples (and related to the likely Picts from Orkney) than to some of his deceased partners at the site. Other samples with sizeable British-like ancestry include VK177 (32.6%, hg. R1b-U152), VK173 (33.3%, hg. I2a1b1a), or VK150 (25.6%, hg. I2a1b1a), while typical Germanic subclades like I1 or R1b-U106 – which may be associated with Anglo-Saxons, too – tend to show less.

late-iron-age-europe-y-dna
Y-DNA haplogroups in Europe during the Late Iron Age. See full map.

I remember some commenter asking recently what would happen to the theory of Proto-Indo-European-speaking R1b-rich Yamnaya culture if Celts expanded with hg. R1a, because there were only one hg. R1b and one (possibly) G2a from Hallstatt. As it turns out, they were mostly R1b. However, the increasingly frequent obsession of searching for specific haplogroups and ancestry during the Iron Age and the Middle Ages is weird, even as a desperate attempt, because:

  1. it is evident that the more recent the ancient DNA samples are, the more they are going to resemble modern populations of the same area, so ancient DNA would become essentially useless;
  2. cultures from the early Iron Age onward (and even earlier) were based on increasingly complex sociopolitical systems everywhere, which is reflected in haplogroup and ancestry variability, e.g. among Balts, East Germanic peoples, Slavs (of hg. E1b-V13, I2a-L621), or Tocharians.

In fact, even the finding of hg. R1b among Celts of central and western Europe during the Iron Age is rather unenlightening, because more specific subclades and information on ancestry changes are needed to reach any meaningful conclusion as to migration vs. acculturation waves of expanding Celtic languages, which spread into areas that were mostly Indo-European-speaking since the Bell Beaker expansion.

Afanasevo ancestry in Asia

Wang and colleagues continue to publish interesting analyses, now in the preprint Inland-coastal bifurcation of southern East Asians revealed by Hmong-Mien genomic history, by Xia et al. bioRxiv (2019).

Interesting excerpt (emphasis mine):

Although the Devil’s Cave ancestry is generally the predominant East Asian lineage in North Asia and adjacent areas, there is an intriguing discrepancy between the eastern [Korean, Japanese, Tungusic (except northernmost Oroqen), and Mongolic (except westernmost Kalmyk) speakers] and the western part [West Xiōngnú (~2,150 BP), Tiānshān Hun (~1,500 BP), Turkic-speaking Karakhanid (~1,000 BP) and Tuva, and Kalmyk]. Whereas the East Asian ancestry of populations in the western part has entirely belonged to the Devil’s Cave lineage till now, populations in the eastern part have received the genomic influence from an Amis-related lineage (17.4–52.1%) posterior to the presence of the Devil’s Cave population roughly in the same region (~7,600 BP)12. Analogically, archaeological record has documented the transmission of wet-rice cultivation from coastal China (Shāndōng and/or Liáoníng Peninsula) to Northeast Asia, notably the Korean Peninsula (Mumun pottery period, since ~3,500 BP) and the Japanese archipelago (Yayoi period, since ~2,900 BP)2. Especially for Japanese, the Austronesian-related linguistic influence in Japanese may indicate a potential contact between the Proto-Japonic speakers and population(s) affiliating to the coastal lineage. Thus, our results imply that a southern-East-Asian-related lineage could be arguably associated with the dispersal of wet-rice agriculture in Northeast Asia at least to some extent.

afanasevo-namazga-devils-gate-xiongnu-huns-tianshan-admixture
Spatial and temporal distribution of ancestries in East Asians. Reference populations and corresponding hypothesized ancestral populations: (1) Devil’s Cave (~7,600 BP), the northern East Asian lineage; (2) Amis, the southern East Asian lineage (= AHM + AAA + AAN); (3) Hòabìnhian (~7,900 BP), a lineage related to Andamanese and indigenous hunter-gatherer of MSEA; (4) Kolyma (~9,800 BP), “Ancient Palaeo-Siberians”; (5) Afanasievo (~4,800 BP), steppe ancestry; (6) Namazga (~5,200 BP), the lineage of Chalcolithic Central Asian. Here, we report the best-fitting results of qpAdm based on following criteria: (1) a feasible p-value (&mt; 0.05), (2) feasible proportions of all the ancestral components (mean &mt; 0 and standard error < mean), and (3) with the highest p-value if meeting previous conditions.

In this case, the study doesn’t compare Steppe_MLBA, though, so the findings of Afanasievo ancestry have to be taken with a pinch of salt. They are, however, compared to Namazga, so “Steppe ancestry” is there. Taking into account the limited amount of Yamnaya-like ancestry that could have reached the Tian Shan area with the Srubna-Andronovo horizon in the Iron Age (see here), and the amount of Yamnaya-like ancestry that appears in some of these populations, it seems unlikely that this amount of “Steppe ancestry” would emerge as based only on Steppe_MLBA, hence the most likely contacts of Turkic peoples with populations of both Afanasievo (first) and Corded Ware-derived ancestry (later) to the west of Lake Baikal.

(1) The simplification of ancestral components into A vs. B vs. C… (when many were already mixed), and (2) the simplistic selection of one OR the other in the preferred models (such as those published for Yamnaya or Corded Ware), both common strategies in population genomics pose evident problems when assessing the actual gene flow from some populations into others.

Also, it seems that when the “Steppe”-like contribution is small, both Yamnaya and Corded Ware ancestry will be good fits in admixed populations of Central Asia, due to the presence of peoples of EHG-like (viz. West Siberia HG) and/or CHG-like (viz. Namazga) ancestry in the area. Unless and until these problems are addressed, there is little that can be confidently said about the history of Yamnaya vs. Corded Ware admixture among Asian peoples.

Maps, maps, and more maps

As you have probably noticed if you follow this blog regularly, I have been experimenting with GIS software in the past month or so, trying to map haplogroups and ancestry components (see examples for Vikings, Corded Ware, and Yamnaya). My idea was to show the (pre)historical evolution of ancestry and haplogroups coupled with the atlas of prehistoric migrations, but I have to understand first what I can do with GIS statistical tools.

My latest exercise has been to map modern haplogroup distribution (now added to the main menu above) using data from the latest available reports. While there have been no great surprises – beyond the sometimes awful display of data by some papers – I think it is becoming clearer with each new publication how wrong it was for geneticists to target initially those populations considered “isolated” – hence subject to strong founder effects – to extrapolate language relationships. For example:

  • The mapping of R1b-M269, in particular basal subclades, corresponds nicely with the Indo-European expansions.
  • There is no clear relationship of R1b, not even R1b-DF27 (especially basal subclades), with Basques. There is no apparent relationship between the distribution of R1b-M269 and some mythical non-Indo-European “Old Europeans”, like Etruscans or Caucasian speakers, either.
  • Basal R1a-M417 shows an interesting distribution, as do maps of basal Z282 and Z93 subclades, despite the evident late bottlenecks and acculturation among Slavs.
  • The distribution of hg. N1a-VL29 (and other N1a-L392 subclades) is clearly dissociated from Uralic peoples, and their expansion in the whole Baltic Sea during the Iron Age doesn’t seem to be related to any specific linguistic expansion.
  • haplogroup-n1a-vl29
    Modern distribution of haplogroup N1a-VL29. See full map.
  • Even the most recent association in Post et al. (2019) with hg. N1a-Z1639 – due to the lack of relationship of Uralic with N1a-VL29 – seems like a stretch, seeing how it probably expanded from the Kola Peninsula and the East Urals, and neither the Lovozero Ware nor forest hunter-fishers of the Cis- and Trans-Urals regions were Uralic-speaking cultures.
  • The current prevalence of hg. R1b-M73 supports its likely expansion with Turkic-speaking peoples.
  • The distribution of haplogroup R1b-V88 in Africa doesn’t look like it was a mere founder effect in Chadic peoples – although they certainly underwent a bottleneck under it.
  • The distribution of R1a-M420 (xM198) and hg. R1b-M343 (possibly not fully depicted in the east) seem to be related to expansions close to the Caucasus, supporting once more their location in Eastern Europe / West Siberia during the Mesolithic.
  • The mapping of E1b-V13 and I-M170 (I haven’t yet divided it into subclades) are particularly relevant for the recent eastward expansion of early Slavic peoples.

All in all, modern haplogroup distribution might have been used to ascertain prehistoric language movements even in the 2000s. It was the obsession with (and the wrong assumptions about) the “purity” of certain populations – say, Basques or Finns – what caused many of the interpretation problems and circular reasoning we are still seeing today.

I have also updated maps of Y-chromosome haplogroups reported for ancient samples in Europe and/or West Eurasia for the Early Eneolithic, Early Chalcolithic, Late Chalcolithic, Early Bronze Age, Middle Bronze Age, Late Bronze Age, Early Iron Age, Late Iron Age, Antiquity, and Middle Ages.

Haplogroup inference

I have also tried Yleaf v.2 – which seems like an improvement over the infamous v.1 – to test some samples that hobbyists and/or geneticists have reported differently in the past. I have posted the results in this ancient DNA haplogroup page. It doesn’t mean that the inferences I obtain are the correct ones, but now you have yet another source to compare.

Not many surprises here, either:

  • M15-1 and M012, two Proto-Tocharians from Shirenzigou, are of hg. R1b-PH155, not R1b-M269.
  • I0124, the Samara HG, is of hg. R1b-P297, but uncertain for both R1b-M73 and R1b-M269.
  • I0122, the Khvalynsk chieftain, is of hg. R1b-V1636.
  • I2181, the Smyadovo outlier of poor coverage, is possibly of hg. R, and could be of hg. R1b-M269, but could also be even non-P.
  • I6561 from Alexandria is probably of hg. R1a-M417, likely R1a-Z645, maybe R1a-Z93, but can’t be known beyond that, which is more in line with the TMRCA of R1a subclades and the radiocarbon date of the sample.
  • I2181, the Yamnaya individual (supposedly Pre-R1b-L51) at Lopatino II is R1b-M269, negative for R1b-L51. Nothing beyond that.

You can ask me to try mapping more data or to test the haplogroup of more samples, provided you give me a proper link to the relevant data, they are interesting for the subject of this blog…and I have the time to do it.

Related

Haplogroup R1b-M167/SRY2627 linked to Celts expanding with the Urnfield culture

bronze-age-late-urnfield

As you can see from my interest in the recently published Olalde et al. (2019) Iberia paper, once you accept that East Bell Beakers expanded North-West Indo-European, the most important question becomes how did its known dialects spread to their known historic areas.

We already had a good idea about the expansion of Celts, based on proto-historical accounts, fragmentary languages, and linguistic guesstimates, but the connection of Celtic with either Urnfield or slightly later Hallstatt/La Tène was always blurred, due to the lack of precise data on population movements.

The latest paper on Iberia is interesting for many details, such as:

  • The express dismissal of the newest pet theory based on the simplistic “steppe ancestry = IE”: the obsessive comparisons of Dutch Bell Beakers as the origin of basically anything that moves in Europe.
  • A discrete influx of North African ancestry in certain samples before the Moorish invasion (which was probably mediated by peoples of North African rather than Levantine admixture).
  • The finding of very Mycenaean-like Greek colonies of the 5th century (interestingly, under R1b lineages).
iberia-celts-romans
Modified from section of PCA of ancient samples by Olalde et al. (2019). “IE Iberia” refers to Pre-Celtic Indo-European languages of Iberia, such as Galaico-Lusitanian in the west (see more on Lusitanian), and a potentially Ligurian-related language in the North-East and southern France.

The paper is, however, of particular importance from the perspective of historical linguistics. It confirms that:

  • Celtic-speaking peoples expanded in Iberia likely during the Late Bronze Age – Early Iron Age (probably with the Urnfield culture, before 1000 BC) with North/Central European ancestry.

NOTE. The paper marks what are believed to be the boundaries of non-Indo-European languages during the Iron Age in later times, extrapolating that situation to the past. Mediterranean sites with Iberian traits (ca. 6th century on) were probably non-Indo-European-speaking tribes, but it is unclear what happened in the centuries before their sampling, and there are no clear boundaries. These incoming Celts from central Europe with the Urnfield culture makes it very likely that the Iberian expansion to the north happened later, incorporating thus this central European ancestry in the process. The southern (orientalizing, Tartessian) site of La Angorrilla shows incineration and influence from Phoenician settlers, and their actual language is also far from clear. The other investigated samples, with higher central European contribution, are from Celtiberian sites.

  • The slightly later arrival of (Phoenician, Greek and) Latin-speaking peoples into Iberia is marked by Central/Eastern Mediterranean and North African ancestry.
iberia-migrations-celts-romans
Expansion of different ancestry components in Iberia during Prehistory. Modified from Olalde et al. (2019) to include labels with populations expanding with each component.

While both confirm what was more or less already known about the oldest attested NWIE dialects, and further support the role of East Bell Beakers in expanding North-West Indo-European, the first part is interesting for two main reasons:

  1. Koch’s Celtic from the West hypothesis, which made a recent comeback with a renewed model based on “steppe ancestry”, is once again rejected in population genomics, as expected. At this point I doubt this will mean anything to the supporters of the theory (because you can propose as many “Celtic-over-Celtic” layers as you want), but if you are not obsessed with autochthonous continuity of Celtic languages in the Atlantic area we might begin to judge the most correct dialectal split (and thus classification) among those proposed to date, based on ancestry and haplogroup expansions.
  2. We believed in the 2000s that the expansion of haplogroup R1b-M167 (TMRCA ca. 1100 BC for YTree or 1700 BC for YFull) was coupled with the expansion of Iberians from the Pyrenees, in turn (thus) closely related to Basques. This non-IE presence has been contested with toponymic data in linguistics, and with the testing of many modern samples and the subsequent discovery of the widespread distribution of the subclade in western and northern Europe. Now it has become even more likely (lacking confirmation with aDNA) that this haplogroup expanded with Celts.

NOTE. Regarding R1b SNPs, YTree has more samples (and thus more SNPs) to work with estimates, due to its connection with FTDNA groups, so it is in principle more reliable (although estimates were calculated in 2017). Nevertheless, the methods to estimate the age of the MRCA are different between YTree and YFull.

df27-m167-z262-mcdonald
YTree estimations of TMRCA for R1b-Z262 (left) and R1b-M167 (right).

Why this is important has to do with the realization that Celts must have expanded explosively in all directions during the estimated range for Common Celtic (ca. 1500-1000 BC), and as such R1b-M167 is probably going to be one of the clear Y-DNA markers of the Celtic expansion, when it appears in the ancient DNA record, maybe in new SNP calls from samples of the Olalde et al. (2019) paper, or in future Urnfield/Hallstatt/La Tène papers.

Sister clades derived from R1b-Z262 (TMRCA ca. 1650 BC for YTree, or 2700 for YFull), although sharing a quite old origin, may have taken part in the same communities that expanded R1b-M167, likely from some point in central Europe, possibly as remnants of a previous (Tumulus culture?) central European expansion, as the sample SZ5 from Szólád (R1b-CTS1595) and the distribution of modern samples suggest.

r1b-df27-m167-sry2627
Left: Modern distribution of upstream clade L176.2 (YFull R1b-CTS4188); Right: Modern distribution of M167. Both include later expansions within Iberia (probably with the Crown of Aragon during the Reconquista). Contour maps of the derived allele frequencies of the SNPs analyzed in Solé-Morata et al. (2017).

EDIT (23 APRIL): In Hernández et al. (2018), the TMRCA of R1b-M167 is reported as 3372-3718 ybp:

The youngest sub-branch, R1b-M167, dates to approximately 3.5 kya (95% CI= 2.5-5.3 kya), i.e. even after the Bronze Age.

r1b-df27-m167-europe
Contour (surface) maps displaying the frequencies of Y-chromosome haplogroup and its sub-lineages across Europe and the Mediterranean basin. Modified from Hernández et al. (2018).

NOTE. Admittedly, the maps are mainly based on Iberian samples and certain limited sampling elsewhere, so most of the frequencies displayed in other territories are extrapolated. Since the percentage of R1b-M167 in France is estimated to be ca. 3%, and in Bavaria ca. 5%, the distribution in Central Europe is probably much higher, and around the Mediterranean much lower than represented in them.

The Celtic expansion might not have been a mass migration of peoples replacing all male lines of their controlled territories (as was common in the Neolithic and Chalcolithic), because of the Bronze Age dominant chiefdom-based system that relied on alliances, but it is becoming clear that Early Celts are also going to show the expansion of certain successful male lineages.

Oh, and you can say goodbye to the autochthonous “Vasconic = R1b-DF27” (latest heir of the “Vasconic = R1b-P312”) theory, too, if – for some strange reason – you hadn’t already.

EDIT (16 MAR) Just in case the wording is not clear: the fact that this haplogroup most likely expanded with Celts does not mean that its lineages didn’t become eventually incorporated into Iberian cultures and adopted non-IE languages: some of them probably did at some point, in some regions of northern Iberia, and most were certainly later incorporated to the Roman civilization and spoke Latin, then to the medieval kingdoms with their languages, and so on until the present day… Only those eventually associated with Iron Age Aquitanians may have retained their non-IE language, unless those lineages today associated with Basques were incorporated later to the Basque-speaking regions by expanding medieval kingdoms. A complex picture repeated everywhere in Europe: no haplogroup+language continuity in sight, anywhere.

NOTE: This here is currently the most likely interpretation of data based on estimations of mutations; it is not confirmed with ancient samples.

Related

On Latin, Turkic, and Celtic – likely stories of mixed societies and little genetic impact

celtic-europe-national-geographic

Recent article on The Conversation, The Roman dead: new techniques are revealing just how diverse Roman Britain was, about the paper (behind paywall) A Novel Investigation into Migrant and Local Health-Statuses in the Past: A Case Study from Roman Britain, by Redfern et al. Bioarchaeology International (2018), among others.

Interesting excerpts about Roman London:

We have discovered, for example, that one middle-aged woman from the southern Mediterranean has black African ancestry. She was buried in Southwark with pottery from Kent and a fourth century local coin – her burial expresses British connections, reflecting how people’s communities and lives can be remade by migration. The people burying her may have decided to reflect her life in the city by choosing local objects, but we can’t dismiss the possibility that she may have come to London as a slave.

The evidence for Roman Britain having a diverse population only continues to grow. Bioarchaeology offers a unique and independent perspective, one based upon the people themselves. It allows us to understand more about their life stories than ever before, but requires us to be increasingly nuanced in our understanding, recognising and respecting these people’s complexities.

We already have a more or less clear idea about how little the Roman conquest may have shaped the genetic map of Europe, Africa, or the Middle East, in contrast to other previous or later migrations or conquests.

Also, on the Turkic expansion, the recent paper of Damgaard et al. (Nature 2018) stated:

In the sixth century AD, the Hunnic Empire had been broken up and dispersed as the Turkic Khaganate assumed the military and political domination of the steppes22,23. Khaganates were steppe nomad political organizations that varied in size and became dominant during this period; they can be contrasted to the previous stateless organizations of the Iron Age24. The Turkic Khaganate was eventually replaced by a number of short-lived steppe cultures25 (…).

We find evidence that elite soldiers associated with the Turkic Khaganate are genetically closer to East Asians than are the preceding Huns of the Tian Shan mountains (Supplementary Information section 3.7). We also find that one Turkic Khaganate-period nomad was a genetic outlier with pronounced European ancestries, indicating the presence of ongoing contact with Europe (…).

turk-medieval-populations
Analyses of Turk- and Medieval-period population clusters. a, PCA of Tian Shan Hun, Turk, Kimak, Kipchack, Karakhanid and Golden Horde, including 28 individuals analysed at 242,406 autosomal SNP positions. b, Results for model-based clustering analysis at K = 7. Here we illustrate the admixture analyses with K = 7 as it approximately identifies the major component of relevance (Anatolian/ European farmer component, Caucasian ancestry, EHG-related ancestry and East Asian ancestry).”

These results suggest that Turkic cultural customs were imposed by an East Asian minority elite onto central steppe nomad populations, resulting in a small detectable increase in East Asian ancestry. However, we also find that steppe nomad ancestry in this period was extremely heterogeneous, with several individuals being genetically distributed at the extremes of the first principal component (Fig. 2) separating Eastern and Western descent. On the basis of this notable heterogeneity, we suggest that during the Medieval period steppe populations were exposed to gradual admixture from the east, while interacting with incoming West Eurasians. The strong variation is a direct window into ongoing admixture processes and the multi-ethnic cultural organization of this period.

We already knew that the expansion of the La Tène culture, associated with the expansion of Celtic languages throughout Europe, was probably not accompanied by massive migrations (from the IEDM, 3rd ed.):

The Mainz research project of bio-archaeometric identification of mobility has not proven to date a mass migration of Celtic peoples in central Europe ca. 4th-3rd centuries BC, i.e. precisely in a period where textual evidence informs of large migratory movements (Scheeres 2014). La Tène material culture points to far-reaching inter-regional contacts and cultural transfers (Burmeister 2016).

Also, from the latest paper on Y-chromosome bottleneck:

[The hypothesis of patrilineal kin group competition] has an added benefit in that it could explain the temporal placement of the bottleneck if competition between patrilineal kin groups was the main form of intergroup competition for a limited episode of time after the Neolithic transition. Anthropologists have repeatedly noted that the political salience of unilineal descent groups is greatest in societies of ‘intermediate social scale’ (Korotayev47 and its citations on p. 2), which tend to be post-Neolithic small-scale societies that are acephalous, i.e. without hierarchical institutions48. Corporate kin groups tend to be absent altogether among mobile hunter gatherers with few defensible resource sites or little property (Kelly49 pp. 64–73), or in societies utilizing relatively unoccupied and under-exploited resource landscapes (Earle and Johnson50 pp. 157–171). Once they emerge, complex societies, such as chiefdoms and states, tend to supervene the patrilineal kin group as the unit of intergroup competition, and while they may not eradicate them altogether as sub-polity-level social identities, warfare between such kin groups is suppressed very effectively51,52.These factors restrict the social phenomena responsible for the bottleneck to the period after the initial Neolithic but before the emergence of complex societies, which would place the bottleneck-generating mechanisms in the right period of time for each region of the Old World.

chalcolithic_late_Europe_Bell_Beaker
Diachronic map of Late Copper Age migrations including Classical Bell Beaker (east group) expansion from central Europe ca. 2600-2250 BC

However, I recently read in a forum for linguists that the expansion of East Bell Beakers overwhelmingly of R1b-L21 subclades in the British Isles “poses a problem”, in that it should be identified with a Celtic expansion earlier than traditionally assumed…

That interpretation would be in line with the simplistic maps we are seeing right now for Bell Beakers (see below for the Copenhagen group).

If anything, the results of Bell Beaker expansions (taken alone) would seem to support a model similar to Cunliffe & Koch‘s hypotheses of a rather early Celtic expansion into Great Britain and Iberia from the Atlantic.

invasion-from-the-steppe-yamnaya
Spread of Indo-European languages (by the Copenhagen group).

But it doesn’t. Mallory already explained why in Cunliffe & Koch’s series Celtic from the West: the Bell Beaker expansion is too early for that; even for Italo-Celtic. It should correspond to North-West Indo-European speakers.

Not every population movement that is genetically very significant needs to be significant for the languages attested much later in the region.

This should be obvious to everyone with the many examples we already have. One of the least controversial now would probably be the expansion of R1b-DF27, widespread in Iberia probably at roughly the same time as R1b-L21 was in Great Britain, and still pre-Roman Iberians showed a mix of non-Indo-European languages, non-Celtic languages (at least Galaico-Lusitanian), and also some (certain) Celtic languages. And modern Iberians speak Romance languages, without much genetic impact from the Romans, either…

It is well-established in Academia that the expansion of La Tène is culturally associated with the spread of Celtic languages in Europe, including the British Isles and Iberia. While modern maps of U152 distribution may correspond to the migration of early Celts (or Italo-Celtic speakers) with Urnfield/Hallstatt, the great Celtic expansion across Europe need not show a genetic influence greater than or even equal to that of previous prehistoric migrations.

post-bell-beaker-europe
Post-Bell-Beaker Europe, after ca. 2200 BC.

You can see in these de novo models the same kind of invented theoretical ‘problem’ (as Iosif Lazaridis puts it) that we have seen with the Corded Ware showing steppe ancestry, with Old Hittite samples not showing EHG ancestry, or with CHG ancestry appearing north of the Caucasus but no EHG to the south.

However you may want to explain all these errors in scientific terms (selection bias, under-coverage, over-coverage, faulty statistical methods, etc.), these interpretations were simply fruit of the lack of knowledge of the anthropological disciplines at play.

Let’s hope the future paper on Celtic expansion takes this into consideration.

Related: