Tracing the Spread of Celtic Languages using Ancient Genomics

[Riverman]

Tracing the Spread of Celtic Languages using Ancient Genomics

Abstract

Celtic languages, including Irish, Scottish Gaelic, Welsh and Breton, are today restricted to the Northern European Atlantic seaboard. However, between 3 and 2 thousand years before present (BP) Celtic was widely spoken across most of Europe. While often associated with Bell Beaker-related populations, the spread of this prominent Indo-European linguistic cluster remains debated1—7. Previous genomic investigations have focused on its arrival to specific regions: Britain8, Iberia9 and Southwestern Germany10. Here, we utilize new genomic data from Bronze and Iron Age Europe to investigate the population history of historically Celtic-speaking regions, and test different linguistic theories on the origins and early spread of the Celtic languages. We identify a widespread demographic impact of the Central European Urnfield Culture. We find ancestry associated with its Knovíz subgroup in the Carpathian Basin to have formed between 4—3.2 kyr BP, and subsequently expanded across much of Western Europe between 3.2 and 2.8 kyr BP. This ancestry further persisted into the Hallstatt Culture of France, Germany and Austria, impacting Britain by 2.8 kyr BP and Iberia by 2.5 kyr BP. These findings support models of an Eastern Central rather than a Western European center of spread for a major component of all the attested Celtic languages. Our study demonstrates, yet again, the power of ancient population genomics in addressing long-standing debates in historical linguistics.

Sequence data for the new 578 ancient genomes can be found in the ENA under accession:
xxxxxxxx.

No data available yet.

https://www.biorxiv.org/content/10.1101/...40770v1?ct=

If I am reading the supplementary correctly there are two Finnish iron age samples with decent quality!

https://genarchivist.net/showthread.php?...0#pid47480

The paper concentrates on the amounts of different early farmer/Neolithic ancestries and being able to, if done correctly, to identify specific mass migrations into Celtic areas. Most notable, it seems to prove, going by the text, what I always considered the likeliest option, that there was a massive influx of continental ancestry into the British Isles after the initial settlement by the Bell Beakers:

For England, we find a series of transitions in the prominent farming ancestries present for212
each time slice (Fig. 3). Initially, between 4800–4000 BP, we find a individuals are modelled213
with a high proportion of Bell Beaker related ancestry, and the tendency to have a slightly214
higher proportion of local British-Irish Isles Neolithic ancestry, relative to the other215
Neolithic-related ancestries. By the Middle Bronze Age (4000–3200 BP), the highest Farmer-216
related ancestry is French/Iberian Neolithic-related rather than the local Neolithic ancestry,217
consistent with recent studies suggesting migrations from the mainland8,36. This migration,218
specifically the Iberian connection, is further supported by evidence that the UK received219
copper from Iberia during this phase (3350/3250–750 BP)41. However, in the Late Bronze220
Age, we see a shift, in which the proportion of Italian Neolithic ancestry has increased to221
similar proportions to that of French/Iberian Neolithic. In the Iron Age, similar patterns are222
seen, with the additional appearance of Bronze Age Anatolian-related ancestry. The changes223
in Farming ancestry present are suggestive of migrations from distinct regions of Europe in224
which local farming ancestry was incorporated.

I consider the last shifts to be the most important, especially since it would relate to the "Italian-like" Tumulus culture core of early Celts during the Urnfield period, with additional Carpatho-Balkan during Urnfield into Iron Age. Same pattern in France, with an apparently massive shift from Franko-Iberian Atlantic facade ancestry to "Italian-like":

In France, we see a similar transition (Fig. 3). During the Early and Middle Bronze Age,227

more local French/Iberian- than Italian Neolithic-related ancestry tends to be present. By the228
Iron Age, the relative proportions have swapped, so Italian Neolithic-related ancestry is the229
highest, accompanied by Bronze Age Anatolian ancestry. Due to the lack of samples from the230
Late Bronze Age, the time of this transition cannot be directly measured. However, the231
increased proportion of Italian Neolithic-related ancestry during the Late Bronze Age on the232
British Isles suggests it was present in France by this time.

That is a clear pattern proving how the Urnfield expansion changed the autosomal make up of the whole Western Celtic sphere, with influences from the Italian-Alpine and Carpathian area.

Further east, in the Czech Republic, we see the increase of Italian Neolithic-related and235

Bronze Age Anatolian-related ancestry between 3200–2800 BP (Fig. 3). We also note that we236
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(which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is
The copyright holder for this preprintthis version posted March 1, 2025.;https://doi.org/10.1101/2025.02.28.640770doi:bioRxiv preprint
detect no evidence of French/Iberian Neolithic ancestry. By splitting further into the cultural237
phases for the region, we find that this ancestry profile in the Czech Republic occurred by238
3300 BP, in individuals associated with the Tumulus Culture and continuing into the Knovíz239
and Hallstatt Periods (Extended Data Fig. 1).

The pulse seems to have come the Carpatho-Balkan zone (Urnfielders!):

However,245
while we see a general range reduction of the British and French/Iberian Neolithic-related246
ancestries, we find an increase in the geographical range of the Italian Neolithic-related and247
Bronze Age Anatolian-related ancestries throughout these periods.

Relevant to the appearance of Italian Neolithic and254
Bronze Age Anatolian-related ancestry in Western Europe by the Iron Age, we included255
individuals from Hungary/Serbia (0_3_4_2_2_C_2800+). Consistent with the results found256
from using the Farmer-related ancestries as a proxy, we find the appearance of Bronze Age257
French/Iberian ancestry appearing in England during the Middle Bronze Age, and the258
Hungarian/Serbian Bronze Age reaching widespread distributions during the Iron Age (Fig.259
4). In the Czech Republic, we find almost all individuals being modelled with a large260
proportion of Hungarian/Serbian ancestry during the Late Bronze Age.

The path might have been Tumulus culture expansion to the East/South East, mixing with the local Carpathians and transition to the Urnfield rites, then expansion of these Eastern mixed groups back all over the territories during Urnfield and these being the base for the later Celtic koine:

Next, we included individuals from the Late Bronze Age from the Czech Republic,282
associated with the Urnfield subgroup of the Knovíz Culture, as a source, who were modelled283
above with high proportions of Hungarian/Serbian ancestry (Extended Data Fig. 1). In the284
early Iron Age (2800–2470 BP), we find this ancestry modelled across Western Southern and285
Eastern Central Europe in varying proportions, complemented by more local sources286
(Extended Data Fig. 3.). In England, the highest proportion tends to be modelled as Bell287
Beaker-related, followed by Knovíz-related and French/Iberian Bronze Age-related. In288
contrast, on the mainland, the proportion of ancestry modelled as Bell Beaker-related tends to289
be low or absent, with the Steppe ancestry in these individuals better modelled by the other290
Bronze Age sources, i.e. Bronze Age Knovíz-related, French/Iberia and Hungary/Serbia

The Celtic core being covered by this "backflow migration" from the Carpathian zone:

Compared to England, the impact of Knovíz-related ancestry is particularly high in France,292

Germany and the Czech Republic. In Austria, we note considerable diversity at the293
eponymous Hallstatt site, with individuals modelled with particularly high proportions of294
either Knovíz or Hungarian/Serbia Bronze Age-related ancestry, more similar to Hungary,295
Slovenia and Slovakia, where the Hungarian/Serbian Bronze Age-related ancestry is296
modelled in high proportions.

Knoviz itself is just the result of this admixture from the Eastern Urnfield (Lusatian-Kyjatice-Gáva) sphere.


This ancestry later spread to Scandinavia too - see migration period patterns:

Some of the Migration Period individuals from Britain carry313
high proportions of Knovíz-related ancestry and little to no British-Irish Bronze Age-related,314
suggestive of migrations from or admixture on the continent (Supplementary Figure S1.1).315
Migration Period migrations into Denmark and Sweden detected elsewhere revealed that316
people carrying some continental ancestry12,50, but primarily of Scandinavian ancestry31,317
arrived in Denmark and Southern Sweden by the Viking Period; here we provide further318
insight into the source of the continental ancestry: the influx of small proportions of319
continental ancestry is modelled as Knovíz and Hungary/Serbia Bronze Age-related ancestry,320
generally lacking British-Irish Bronze Age and French/Iberian Bronze Age. As such, we can321
exclude the Netherlands, France, Britain and Ireland as a source of this continental ancestry,322
and infer a source region further east. This stands in direct contrast to Norway, where high323
proportions of the British-Irish Bronze Age-related ancestry are detected in most individuals324
with non-local ancestry, consistent with previous studies50.

This paper seems to prove unambiguously that the Urnfield phenomenon was associated with mass migrations and spread in the Western sphere the Celtic language and culture:

Furthermore, the expansion of Knovíz-related ancestry from Eastern Central Europe detected458
here, continuing into Hallstatt and La Tène populations, provides new evidence supporting459
the linguistic model in which Celtic languages were mediated to France, Britain, Iberia and460
Italy during the Late Bronze Age by populations associated with the Urnfield Culture67,68.461
This aligns with the association of the Lepontic language with the Urnfield-derived462
Golasecca Culture of Northern Italy69, as well as the Urnfield-type weaponry of ~3200–3000463
BP depicted on Late Bronze Age warrior stelae of the Southwestern Iberian Peninsula70–72.

Link: https://www.biorxiv.org/content/10.1101/...1.full.pdf

With the Gomolava samples and other Carpatho-Balkan samples, we might prove, very soon, the same on an even higher level for the Balkans, where these Eastern Urnfielder groups didn't just spread their ancestry indirectly, like in the West, since the dominant factor were the "converted Eastern Tumulus culture" people, but directly, like with Gáva-related Channelled Ware.
Knoviz and the Middle Danubian Urnfield group were kind of a experiment and mixed territory, whereas to the West we primarily deal with the spreads of Proto-Celtic "converts" to the Urnfield religion/package.

[Riverman]

In the supplements they also address the "patrilineage problem":

S3.2. Spatial distribution of subhaplogroups of R-P312 track population movements in247
the Middle and Late Bronze Age248
Haplogroup R-P312 resolves itself in a polytomy, with downstream lineages showing some249
level of geographical structure, particularly among Bronze Age individuals. Subhaplogroup250
R-L21 (and its descendant R-DF13) is predominant in Britain and Ireland; R-DF27 (and R-251
Z195) in Iberia and France; R-U152 (and R-L2) in Central Europe and Northern Italy; and R-252
DF19 and R-Z30597 potentially associated with the Netherlands and Scotland, respectively,253
though sample sizes for these two are very limited. This regional distribution of R-P312254
subhaplogroups provides a framework to explore population movements during the Bronze255
and Iron Ages. Additionally, the European Farmer-related haplogroup G-L497 also seems to256
be a geographically structured lineage, being largely restricted to Central Europe and Italy257
during the Bronze Age, and could also be used to track increased connectivity between258
regions in the archaeogenetic record.
However, it must be noted that, consistent with autosomal DNA evidence, Western Europe261
exhibits a strong paternal lineage continuity from the Bronze Age to the present, particularly262
when considering R-P312 subhaplogroups. In most regions, modern males predominantly263
descend from the same subhaplogroups that were already common in the Bronze Age.264
Notably, in Ireland and the Basque Country, R-L21 and R-DF27, respectively, account for265
over 80% of all present-day male lineages90–95.
Allele-frequency-based 8 and haplotype-based methods detect an arrival of continental268
ancestry in Britain during the Middle Bronze Age (3,200-4,000 BP). Consistent with this, we269
detect the R-DF27 sub haplogroup – associated with France and Iberia – among a few270
individuals during and after the Middle Bronze Age 8,35, which could be evidence of this271
signal of gene flow from these regions. Interestingly, one of these individuals from the272
Middle Bronze Age, from Cliffs End Farm, Kent, was shown to be a genetic and isotopic273
outlier8.
IBD mixture modelling results have demonstrated gene flow between Central Europe276
(specifically, Urnfield-associated Knovíz culture) and Britain and Iberia, who share an277
ancestry source which is also present in Hallstatt, La Tène and other contexts in France and278
Germany. Supporting the autosome evidence, we document multiple occurrences of typically279
Central European lineages R-U152 (and its downstream lineage R-L2) and G-L497 in Britain280
by ~2,300 BP8 and France by ~2,600 BP8,37,55. In the continent, those individuals are mainly281
from Hallstatt, La Tène or Gaulish contexts. Though significantly later, we also find282
haplogroup R-U152 in Medieval Belgium, where Celtic languages had been spoken in the283
Iron Age96.

In Iberia, IBD mixture modelling suggests gene flow with Central Europe to start by 2,500286
BP, but very few male individuals have been previously analyzed from Spain or Portugal287
between the crucial time period between 1,800 and 2,800 BP 8,9 most of them at low288
coverage. Their paternal lineages are dominated by local R-DF27 and its subhaplogroups 65,289
but one individual from Northeastern Spain belongs to haplogroup R-U152 (L2), which can290
be tentatively linked with the Urnfield presence in the region 97. Additionally, three present-291
day Northeastern Spanish individuals from the Iberians from Spain (IBS) 1000 Genomes292
population also carry R-U152 (L2) haplogroups.

Here I must comment on the fact, that if looking for Urnfielder influences, as a rule of thumb, both the first to start and the last to end with the rite of cremation are the most likely to be Urnfielder lineages!
This means any finds and frequencies of Urnfielder-associated haplogroups have to be considered the very lower end of the possible presence. Highly likely, there were many more than that.

From the linguistic perspective:

By the Iron Age, Celtic306 language varieties were spoken across much of Europe. All of these diverged from a common307
linguistic ancestor, Proto-Celtic, or at least from a Common Celtic dialect continuum98, often308
estimated to have existed during the late 4th millennium BP99, cf. c. 3200–2900 BP100, c.309
3205 (2515‒3963 BP)23 or at any rate after the start of the 4th millennium BP101 and before c.310
2600 BP102. On a deeper level, the Celtic branch is widely grouped with the closely related311
Italic branch, ancestral to e.g. Latin, under a Italo-Celtic subclade that arguably also included312
Lusitanian4,103,104, but this subgrouping is not universally accepted105.

This interpretation clearly suggests that Pre-Celtic was spoken in the Italo-Celtic/Kentum continuum of the Tumulus culture and transitioned from a subset of this Tumuluis culture people (those Eastern groups having had contacts to the cremating Carpathian basin locals, in the Danube-Tisza area) to the Urnfield spread of Proto-Celtic (1.200 BC). The main haplogroup of these Eastern Tumulus culture people was R-L2 - notably R-L2 appeared as far as Iberia with the Urnfielders spread.

Just like the presence of sequenced haplogroups from the Urnfielders represent the very lower end of the possible spread, the same applies for the timing:

In483 short, it looks as though Urnfield cultural impact reached wide areas of Iberia by c. 3200 BP,484
but its genetic effects first become evident only several centuries later. Due to the limited485
number of Bronze and Iron Age genomes from the region, the date of 2500 BP should be486
interpreted as a lower limit of the time of arrival, with future samples possibly helping to487
address this issue.

For the heydays of Urnfielders, there is not sufficient sampling! Therefore all these arrival dates are rather the latest for e.g. Iberia.

Inhumation burials are oftentimes irregulars and could even represent slaves - at the same time, the area origin of the cremation rite is clearly the (Eastern) Carpathian basin - resulting in a mixed Tumulus culture-early Urnfielder culture West of the Tisza, whereas the Transtisza locals adopted some innovations from the TC people as well. 

However, this expansion has also been discussed in terms528
of a ritual change from inhumation to cremation that expanded with a new religion but also529
that the pits with inhumations could represent slaves58. The early origin of cremation and the530
use of urns for the bones originated in Hungary from where it spread in subsequent centuries

About the advantages of the Urnfield revolutions (among others):

The Urnfield culture reflects a more collective, centralized social organization based on534
staple finance, i.e. on surplus generated by intensive agrarian regimes, rather than wealth535
finance, while remaining under the strong political leadership of war chiefs167. This536
expansion and associated migrations were rooted in agrarian intensification, with the537
introduction of new crops such as millet and large-scale transformation of landscapes170.538
These advances supported significant population growth and facilitated the spread of the539
Urnfield culture. This in turn is reflected in the formation of large, fortified settlements170.540
Also advanced metalwork of hammered cauldrons and cups for feasting and drinking541
flourished, with centers in Hungary and Bohemia, from where their products were exported542
widely across Europe167.

What they didn't mention is a more "professionalised" warrior caste with a specific warrior ethnos and vastly more advanced weaponry and tactics, most notably Naue II/Reutlingen type slashing swords, long casted spearheads, types of casted arrowheads and larger shields (precursor to hoplite style warfare), which appeared both in the West and East with the expansion of Urnfielders.

An attempt was also made to move northward551
to settle and take control of the metal exchange. This could in turn have led to battle in the552
Tollense valley in Mecklenburg region that included several thousand warriors from south553
Scandinavia, northern Germany and central Europe62.

Note that in the battle of Tollense a wide range of warriors from Tumulus culture people, Eastern Urnfielders (mainly Lusatians) and even Balto-Slavs under Urnfielder control participated. Showing that the Urnfielder elite has created a wide ranging network from which elite forces could be drawn. In the case of Tollense from Southern Germany to around Eastern Poland-Belorussia, from Mecklenburg-North Eastern Germany to Hungary-Transylvania.

Link to the supplements: https://www.biorxiv.org/content/10.1101/...y-material

[Riverman]

From another thread, I think its relevant:

Tracing the Spread of Celtic Languages using Ancient Genomics
Another interesting study, as Davidski had the right instinct and was also of the opinion that the Celtic language has a further eastern origin, so I could imagine the chronology (Carpathian Basin:
Únětice culture - Urnfields / Knovíz culture - Hallstatt culture - La Tène culture (migration to Britain and Iberia) and as mercenaries in Galatia!

I opened a thread on the paper here:
https://genarchivist.net/showthread.php?tid=1496

I don't agree with the starting point, because Unetice was the counter offensive from the Epi-Corded + Carpathian people alliance against Bell Beakers, kind of pushing them back.

While the Urnfielder expansion had a similar context (again the Eastern groups of Lusatians-Kyjatice-Gáva did push TC back), the main spread of the Proto-Celts was associated with the a mixed group of TC-Carpathian people (Middle Danubians rather than Knoviz!) which expanded to the West. So the direct trajectory is Bell Beaker -> Tumulus culture -> Western Urnfielders.

Whereas Unetice were a different people, like speaking a different language, which might have survived into Lusatians (even that is doubtful), possibly, but not into Celts/Western Urnfielders.

The Celts were therefore mixed/converted Tumulus culture people, whereas the Eastern Urnfielders, with which they mixed, and from which they had most of these new customs from, spoke different languages. In my opinion they main Transtisza group (from Eastern cremating Otomani, Wietenberg, Verbicoara etc.) spoke Proto-Thracian and the Lusatians likely another rather Satem related language, probably closest to Balto-Slavic, likely between Germanic and Balto-Slavic.

To make that difference is crucial, since this makes the Celts a "mere backflow", rather than a completely foreign invasion. Which being proven, beside other facts, by the main Proto-Celtic haplgroup being R-L2, which was proven to be the dominant haplogroup in Eastern Tumulus culture people which came into contact with the Eastern Carpathian cremating locals which were very rich in EEF ancestry (Transylvanian continuity since the Bronze Age, hopefully soon published paper).

Groups like Carpathian Tumulus culture/Egyek/Cehalut etc. are fully mixed TC + cremating locals, resulting in this impulse which caused the formation of the Urnfield phenomon/conversion of TC warriors.

Here is a core site, the site of Egyek, in which we can see the mixture of incoming TC with local Carpathians:
https://de.wikipedia.org/wiki/Egyek

TC didn't make it beyond the Tisza river, which was the stand of the local EEF-rich Carpathians which cremated, but in the zone between the Danube and the Tisza, they mixed and beyond those mixed zone innovations and new ideas were exchanged in both directions.

Therefore I think that the mixture took place in the Danube-Tisza zone, and from there the new Proto-Celts spread with the Middle Danubian Urnfielder/Knoviz group Westward.


The main reason for the papers focus on Knoviz, is in my opinion, that the much more central Middle Danubian Urnfield group, which connected Proto-Villanovans in Italy with the East Urnfielder/local people from Lusatians, Kyjatice and Gáva-Holigrady, is simply that they were harder/not to sample, since they way more strictly (like Gáva) did cremate their dead, compared to the less strictly cremating/more sacrificing with irregular burials of the victims, Knoviz group.

Therefore I want to really stress that their focus on Knoviz is primarily due to the sampling bias. The really central group is more likely the Middle Danubian Urnfield group.

[Manofthehour]

So "Celtic From the East" theory appears to be re-strengthened from this as I understand.

[pelop]

Are these new samples different from the new samples in the McColl et al Germanic dispersal paper?

[teepean]

Are these new samples different from the new samples in the McColl et al Germanic dispersal paper?

Looks like the samples are included in that paper as well.

[Stefano]

Congratulations to the authors for completely ignoring all the cisalpine and alpine area and including zero samples from Switzerland and Northern Italy, while including hundreds of Denmark samples. Great job!

[Dewsloth]

Potentially relevant to the Iron Age geographic distribution of Celtic are three later, large scale migrations across Western, Southern and Central Europe, detected in this study. The first is the arrival of (Bell Beaker-related) Steppe ancestry between 4300 and 4000 BP, with
 origins around the Netherlands and Northern France. Two others occurred in the Bronze
Agecf. 8,133 . Of these, the second involves migrations to the British Isles between 4000-2800
 BP, with origins in mainland Western Europe. The final occurred between 3200-2800 BP,
 with origins in Central Europe and associated with spread of the Hallstatt Culture across
 Western Europe, reaching the British Isles by at least 2800 BP, and Iberia by at least 2500
 BP. As such, the suitability of each as a potential vector for Celtic must be considered

Interesting.  But the earliest P312 so far in the Netherlands is older than the Beaker layer at his site...
He's also P312>DF19>Z302, so generations younger than the first P312s.

Also this paper doesn't seem to mention Single Grave Culture at all, unless my searching is glitching.

[Riverman]

Congratulations to the authors for completely ignoring all the cisalpine and alpine area and including zero samples from Switzerland and Northern Italy, while including hundreds of Denmark samples. Great job!

Absolutely. The question is whether there are testable samples from these areas for the Urnfield period.
But Yeah, still a huge gap and Knoviz is likely just a proxy for the actual central Alpine-Danubian groups.

[Orentil]

Congratulations to the authors for completely ignoring all the cisalpine and alpine area and including zero samples from Switzerland and Northern Italy, while including hundreds of Denmark samples. Great job!

Absolutely. The question is whether there are testable samples from these areas for the Urnfield period.
But Yeah, still a huge gap and Knoviz is likely just a proxy for the actual central Alpine-Danubian groups.

First question is if there are samples, second question is if you get access to them and / or if another working group was faster getting the rights. There is not only cooperation but also a tough competition out there ;-)

[pelop]

Also this paper doesn't seem to mention Single Grave Culture at all, unless my searching is glitching.

I don't think Single Grave Culture is very relevant to these topics, I feel like this is one of the cultures whose importance has been overblown in anthro-hobbyist circles.

[J1_DYS388=13]

So "Celtic From the East" theory appears to be re-strengthened from this as I understand.

But the "Celtic From the West" is also supported, at least for the British-Irish Isles:

"Previous studies 450 have indeed highlighted the possibility that Celtic languages, specifically the linguistic 451 predecessors of Goidelic and Brittonic, were introduced to Britain from France during the Middle to Late Bronze Age7 452 . This is supported by our own detection of France/Iberia Bronze 453 Age-related ancestry and consistent with Atlantic models suggesting that Celtic emerged in Central-West Europe1,41 454 . However, we find no evidence of this ancestry reaching Eastern 455 Central Europe, where Celtic was spoken during the Iron Age, indicating that this migration 456 does not account for the spread of Celtic as a whole."

[Riverman]

So "Celtic From the East" theory appears to be re-strengthened from this as I understand.

But the "Celtic From the West" is also supported, at least for the British-Irish Isles:

"Previous studies 450 have indeed highlighted the possibility that Celtic languages, specifically the linguistic 451 predecessors of Goidelic and Brittonic, were introduced to Britain from France during the Middle to Late Bronze Age7 452 . This is supported by our own detection of France/Iberia Bronze 453 Age-related ancestry and consistent with Atlantic models suggesting that Celtic emerged in Central-West Europe1,41 454 . However, we find no evidence of this ancestry reaching Eastern 455 Central Europe, where Celtic was spoken during the Iron Age, indicating that this migration 456 does not account for the spread of Celtic as a whole."

That's not correct, because in the text and supplement, they directly and correctly dissociate this EBA-MBA "Atlantic facade" connections from the Celtic ethnolinguistic group. There is no separate British solution possible. And the Urnfield influx into Britain was probably diminished, compared to the continent, but still powerful enough, to cause a shift to the Celtic networks.

A huge problem for the British Isles is the sampling gap. Because I wouldn't wonder if the initial "actual Celtic" impact from the continent was bigger than what remained from it over time, since in many such instances, where there was no complete/large scale replacement of the locals, the people in the centres get pushed back demographically by the countryside, where more local ancestry persisted.

[Orentil]

Also this paper doesn't seem to mention Single Grave Culture at all, unless my searching is glitching.

I don't think Single Grave Culture is very relevant to these topics, I feel like this is one of the cultures whose importance has been overblown in anthro-hobbyist circles.

I agree that SGC has no relevance for Celts and Celtic language, but I assume it is very important to understand the spread of R1b-U106.

[Riverman]

Also this paper doesn't seem to mention Single Grave Culture at all, unless my searching is glitching.

I don't think Single Grave Culture is very relevant to these topics, I feel like this is one of the cultures whose importance has been overblown in anthro-hobbyist circles.

I agree that SGC has no relevance for Celts and Celtic language, but I assume it is very important to understand the spread of R1b-U106.

In which case it would be rather Pre-Germanic instead of Pre-Celtic, just saying. Because R-U106 seems to be at the root of the Proto-Germanic expansion and I-M253 seems to have joined secondarily IMHO.