Population Replacement in Early Neolithic Britain-inc. Cheddar Man

[Angela]

See:Selina Brace et al (inc. Chris Stringer, David Reich, Mark Thomas, and Ian Barnes)

"Population Replacement in Early Neolithic Britain"
https://www.biorxiv.org/content/bior...67443.full.pdf

"The roles of migration, admixture and acculturation in the European transition tofarming have been debated for over 100 years. Genome-wide ancient DNA studiesindicate predominantly Anatolian ancestry for continental Neolithic farmers, but alsovariable admixture with local Mesolithic hunter-gatherers1-9. Neolithic cultures firstappear in Britain c. 6000 years ago (kBP), a millennium after they appear in adjacentareas of northwestern continental Europe. However, the pattern and process of theBritish Neolithic transition remains unclear10-15. We assembled genome-wide datafrom six Mesolithic and 67 Neolithic individuals found in Britain, dating from 10.5-4.5kBP, a dataset that includes 22 newly reported individuals and the first genomic datafrom British Mesolithic hunter-gatherers. Our analyses reveals persistent geneticaffinities between Mesolithic British and Western European hunter-gatherers over aperiod spanning Britain’s separation from continental Europe. We find overwhelmingsupport for agriculture being introduced by incoming continental farmers, with smalland geographically structured levels of additional hunter-gatherer introgression. Wefind genetic affinity between British and Iberian Neolithic populations indicating thatBritish Neolithic people derived much of their ancestry from Anatolian farmers whooriginally followed the Mediterranean route of dispersal and likely entered Britain fromnorthwestern mainland Europe."



I guess they felt beleaguered enough that they had to release the paper early.

[Angela]

Some other interesting bits:

"Comparison of British Mesolithic samples to different Mesolithic WHGs (Loschbour -Luxembourg, La Brana - Spain, KO1 - Hungary; Supplementary Figures S5-S6) indicatesthat they all resemble Loschbour most closely (i.e. the geographically most proximateMesolithic genome available)."

"The majority (~75%) of ancestry in all British Neolithic individualscould be attributed to ANFs."

"individuals from Wales retain the lowest levels of WHG admixture, followed bythose from South-West and Central England. South East England and Scotland show thehighest WHG admixture proportions. These proportions remain stable for over a millennium,from the Early into the Middle/Late Neolithic."

"For all of our BritishNeolithic individuals we inferred more shared drift with Early Neolithic Iberians; for themajority of comparisons this was significant (Figure 4A, Supplementary Figure S9). To inferlevels of WHG introgression occurring between Iberian Early Neolithic populations – theclosest currently available attributable source of farmer ancestry in British Early Neolithicgenomes – and early British farmers, we estimated f4 admixture proportions. We detectedlittle excess (~10%) WHG ancestry beyond what was already present in Iberian EarlyNeolithic populations, suggesting small proportions of admixture, particularly in Wales wherewe detected no excess WHG ancestry (Figure 4B)."

Based on the correspondence we saw, the results are slightly different than stated below, aren't they? Did they waffle because of the controversy?

"here we integrate 36 rather than 2 SNPs allowing more preciseprediction26. Cheddar Man is predicted to have had dark or dark to black skin, blue/greeneyes and dark brown possibly black hair, whereas Sven most likely had intermediate to darkskin pigmentation, brown eyes and black possibly dark brown hair (see Pigmentation sectionin the Supplementary Materials for a detailed discussion of the results). This is in line withthe current hypothesis that alleles commonly associated with lighter skin were introduced inWestern Europe by ANFs19."

"We also analysed two previously-published WHGs, and find potential temporal and/orgeographical variation in pigmentation characteristics. Loschbour22 from Luxembourg is~2000 years younger than Cheddar Man, and is predicted to have had intermediate skinpigmentation. Furthermore, the Loschbour individual most likely had blue/green eyes. Incontrast, La Braña18 from northern Spain who is slightly later than Loschbour is predicted tohave had dark to dark to black skin and hazel/green eye colour. Both La Braña andLoschbour were predicted to have had black, possibly dark brown hair. These results implythat quite different skin pigmentation levels coexisted in WHGs at least by around 6000 BC."

"British farmers were substantially descended from Iberian Neolithicrelatedpopulations whose ancestors had expanded along a Mediterranean route2,7,14,although our analyses cannot rule out the possibility that they also inherited a minorityportion of their ancestry from the Danubian route expansion through Central Europe. Indeed,a recent study that investigated continental Neolithic farmer-related ancestry components inNeolithic Britain estimated ⅔ Mediterranean and ⅓ Danubian route8, which may beconsistent with the association between Britain’s more easterly-distributed Carinated Bowltradition14 and the Nord-Pas-de-Calais region of France, as Neolithic people in these regionsof mainland Europe are thought to have interacted with populations of Central EuropeanNeolithic ancestry."

We have pointed out the following on this site:
"We caution that our results should not be interpreted as showing the Iberian Neolithic-relatedancestry in British Neolithic people derives from migrants whose ancestors lived in Iberia, aswe do not have ancient DNA data from yet unidentified source populations — possiblylocated in southern France — that were ancestral to both Iberian and British farmers."

I thought prior British Neolithic samples were closer to Italians than anyone else, yes?

"The limited regional variation in WHG ancestry we see in the British Neolithic samples couldreflect subtle but differing degrees of regional admixture between farmers and foragers,and/or multiple continental source populations carrying varying levels of WHG ancestrycolonising different regions of Britain. What is clear is that across Britain all of our estimatesfor admixture between hunter-gatherers and farmers are very small, and that we find noevidence of WHG ancestry increasing as the British Neolithic progressed over time."

[bicicleur]

I guess they felt beleaguered enough that they had to release the paper early.

the study is about 73 British individuals, while Channel 4 chose to focus on just 1 individuals phenotypes
IMO because it was the best way to generate publicity for their program

none of it is mentioned in the papers abstract

Channel 4 turned a footnote into the main course

[bicicleur]

channel 4 named 10 ka Cheddar man as 'first Brittons', while this paper suggest that mesolithic Britain got extinct 6 ka

Channel 4 said Cheddar man came from Africa via the middle east, I don't find it in this paper

[bicicleur]

are there supplements?
is ther Y-DNA available?

[bicicleur]

in the PCA chart there is some shift to the NE from pleistocene to holocene HG, with British HG in the middle

[bicicleur]

We caution that our results should not be interpreted as showing the Iberian Neolithic-related
ancestry in British Neolithic people derives from migrants whose ancestors lived in Iberia, as
we do not have ancient DNA data from yet unidentified source populations — possibly
located in southern France — that were ancestral to both Iberian and British farmers.
Available Middle Neolithic Iberian individuals are too late to represent the source population
for early British farmers, and there is no archaeological evidence for direct immigration from
Iberia14. The lack of genome-wide data from Neolithic northern France, Belgium and the
Netherlands means that it is not currently possible to identify proximal continental source
populations.

more samples remain to be analysed

[elghund]

The smaller percentage of WHG in Wales correlates with its lower percentage of mtDNA U5.

https://www.eupedia.com/genetics/bri...na.shtml#mtdna

[ThirdTerm]

According to the pigmentation section, Cheddar Man has a higher probability of having intermediate skin color (0.394) than La Braña 1 (0.042), when ancestral alleles are used. The darkest possible skin pigmentation for both La Braña 1 and Cheddar Man is highly unlikely and the authors concede that more research is need to clarify to what degree Cheddar Man has a dark complexion. I think Cheddar Man's facial reconstruction shown on the TV documentary is unusually dark as there is a 39% chance that Cheddar Man's skin pigmentation is in the intermediate range.

La Braña (Spain, Mesolithic)

Prediction range: Very Pale 0 Pale 0 Intermediate 0.042 - 0.205 Dark 0.209 - 0.435 Dark-Black 0.749 - 0.36

Final prediction: Dark/Dark-to-Black skin

Explanation: The combined effect of probabilities in the dark and dark-to-black colour categories provide an indication that the individual has darkly pigmented skin, it is unlikely that this individual has the darkest possible skin pigmentation, however, it cannot be ruled out as the missing marker does influence that detail, but certainly skin colour is dark in complexion.

Cheddar Man (UK, Mesolithic)

Prediction range: Very Pale 0 Pale 0 Intermediate 0.394 - 0.125 Dark 0 - 0 Dark-Black 0.606 - 0.875

Final prediction: Dark/Dark-to-black skin

Explanation: The missing loci certainly impact on this prediction; however utilizing the input of all ancestral alleles is the preferred option over the use of the derived alleles at these loci – hence 0.394 for intermediate and 0.606 for Dark-black would be the most probable profile. That being said a broad range is present in both the intermediate and dark-black categories due to the missing loci. Also this effect, of skipping a skin colour prediction category with regards probability values, tends to be observed more often in admixed individuals. What is important to note is the input of the dark-black prediction is significant on the intermediate category and therefore it is acceptable to propose a dark complexion individual over an intermediate/light prediction even though the intermediate range is large. It is unlikely that this individual has the darkest possible pigmentation, however it cannot be ruled out. Better sequencing coverage would clarify to what degree this individual has a dark complexion.

Cheddar Man's mtDNA haplogroup is confirmed to be U5b1. But there is no data on Y-DNA haplogroups of these ancient samples.

Cheddar_man I6767 (51.281679, -2.765746) NA 8470-8230 BC (9100±100, OxA-814) Early_Mesolithic 2.31635x 85.02269x "1.0
[0.99, 1.0]" U5b1

[Maciamo]

Here is the link to the supplementary material.

Supplementary figure 8 shows the WHG vs Anatolian Neolithic admixture ratio. Not sure how reliable they are, as the Cheddar Man has about 10% of Anatolian Neolithic admixture, in 7000 BCE Britain! Rather unlikely. Maybe Mesolithic East Med of some sort instead, but even that is far-fetched.

The pigmentation alleles are listed in the supplementary tables.

Unfortunately I couldn't find any Y-DNA or mtDNA.

[elghund]

Here is the link to the supplementary material.

Supplementary figure 8 shows the WHG vs Anatolian Neolithic admixture ratio. Not sure how reliable they are, as the Cheddar Man has about 10% of Anatolian Neolithic admixture, in 7000 BCE Britain! Rather unlikely. Maybe Mesolithic East Med of some sort instead, but even that is far-fetched.

The pigmentation alleles are listed in the supplementary tables.

Unfortunately I couldn't find any Y-DNA or mtDNA.

Thanks for posting this link. It looks like Supplemental Table S1 has the mtDNA.

[Angela]

^^The only ones that seem at all unusual are the following:

Late Mesolithic –
V/HV
B5/HV/H13

Neolithic-
M/V/B4
B4A1

The genetic material must have been too degraded to be more precise.

I'm not surprised there isn't all that much WHG in some of these farming people. Some of the levels are about the same as in the EN in Central Europe and Iberia, which was about 10%. Others have more, but I think they're showing the amount they might have brought with them from Europe, and then the small amount that might have been added in Britain itself.

Maybe the difference is that in mainland Europe there was some movement back down south of the WHG from their refuge areas in the far northeast. With water now surrounding Britain it might have been more difficult for hunter-gatherers to migrate there.

This is what I was referring to earlier. Cassidy et al compared Ballynahatty Neolithic sample to modern European populations and got this:



In this it definitely looks more like Cardial to me. As the paper states, there might be some Danubian Neolithic in there depending on the continental take off point. They would have to compare all these populations to see.

[Johane Derite]

Cheddar Man has about 10% of Anatolian Neolithic admixture, in 7000 BCE Britain! Rather unlikely.

I put bars so that it would be more legible. The bar lands on ~6% plus or minus 2.6%. So the low end total is 3.4% and the high end 8.6%.

[FIREYWOTAN]

Thanks for sharing this hypothesis with me it rings truer than might be thought. Yet it still comes down to the depth of research that's available. just as some challenges speak to our psychological soul others are bases in a deeper understanding in a process of thinking about thinking. I'm excited to find answers no matter how we arrive at our conclusions.

[Angela]

David Reich made some comments about this paper in an interview found by Jovialis. I thought it would be helpful to include it in this thread. I think it's moving too, although I think part of the story may be population crash and possibly plague coming with the newcomers. It needn't have been wholesale slaughter. Also, bear in mind that the incomers were probably half MN European farmer, of which 25% perhaps would have been WHG, and the other 75% early Neolithic farmer similar to what was already in Britain.

HMS: You also uncovered some startling information about population replacement in Britain right when Stonehenge was being built.
.REICH: That was one of the most moving things we found. When the Beaker phenomenon spread to Britain for the first time, about 4,400 years ago, it arrived through a movement of people rather than ideas. We see the footprint in the DNA. People in Britain had no ancestry from the Eurasian steppe before this time period. Then the Beakers arrived and there was immediately 90 percent steppe ancestry. That means at least 90 percent of the entire population of Britain was replaced within a few hundred years. It was a huge event.

And it’s not as if the Beaker people were moving into a vacuum. There were people there. These were the people who built Stonehenge. They were still building Stonehenge when the Beaker complex arrived. They were arguably one of the most sophisticated groups in Europe, yet they were overwhelmed, somehow, by the people who brought the Beaker culture.

HMS: Whose job is it to figure out what happened?
REICH: I think it’s the archaeologists’ job.

https://hms.harvard.edu/news/coming-focus

[FIREYWOTAN]

Thanks for making me aware of another opportunity to feel more like a member than an outsider.
Starting from a position of strength. The opportunity to find collaboration of not only articles and books but the commitment of those who work the program with the passion and curiosity that helps to facilitate discovery.