May 28, 2016

British Celts have more steppe ancestry than British English

An interesting tidbit in a preprint about blood pressure genes:
We consistently obtained significantly positive f4 statistics, implying that both the modern Celtic samples and the ancient Saxon samples have more Steppe ancestry than the modern Anglo-Saxon samples from southern and eastern England. This indicates that southern and eastern England is not exclusively a genetic mix of Celts and Saxons.
Southeastern England is genetically very homogeneous. If the people there were a mix of ancient Celts and Saxons you'd expect them to be intermediate between modern Celts (who should have more Celtic ancestry than the modern English) and ancient Saxons (who should have more Saxon ancestry than the modern English).

But, it seems that the English have less steppe ancestry than both modern Celts and ancient Saxons, so they're not really intermediate. My guess is that the English have Norman ancestry that the Celts don't. While the original Normans were Scandinavians with presumably lots of steppe ancestry, I'd be surprised if the post-1066 Normans that settled England were not already heavily admixed with the "French" and so had less steppe ancestry than the modern British Celts from Wales and Scotland.


Population structure of UK Biobank and ancient Eurasians reveals adaptation at genes influencing blood pressure

Kevin Galinsky et al.

Analyzing genetic differences between closely related populations can be a powerful way to detect recent adaptation. The very large sample size of the UK Biobank is ideal for detecting selection using population differentiation, and enables an analysis of UK population structure at fine resolution. In analyses of 113,851 UK Biobank samples, population structure in the UK is dominated by 5 principal components (PCs) spanning 6 clusters: Northern Ireland, Scotland, northern England, southern England, and two Welsh clusters. Analyses with ancient Eurasians show that populations in the northern UK have higher levels of Steppe ancestry, and that UK population structure cannot be explained as a simple mixture of Celts and Saxons. A scan for unusual population differentiation along top PCs identified a genome-wide significant signal of selection at the coding variant rs601338 in FUT2 (p=9.16×10-9). In addition, by combining evidence of unusual differentiation within the UK with evidence from ancient Eurasians, we identified new genome-wide significant (p less than 5×10-8) signals of recent selection at two additional loci: CYP1A2/CSK and F12. We detected strong associations to diastolic blood pressure in the UK Biobank for the variants with new selection signals at CYP1A2/CSK (p=1.10×10-19)) and for variants with ancient Eurasian selection signals in the ATXN2/SH2B3 locus (p=8.00×10-33), implicating recent adaptation related to blood pressure.



wagg said...

"While the original Normans were Scandinavians with presumably lots of steppe ancestry, I'd be surprised if the post-1066 Normans that settled England were not already heavily admixed with the "French" and so had less steppe ancestry than the modern British Celts from Wales and Scotland."

Except that the Norman demographic impact in England is supposed to have been besically nil.

Onur Dincer said...

Too bad that they did not use the Roman-era British samples.

tew said...

The Celtic samples examined here are probably not a good proxy for ancient Celtic admixture. It seems that all "Celtic" samples are from areas heavily affected by Viking invasions/settlements (N Scotland and coastal Wales), so that would explain higher Steppe ancestry. I suspect inland Wales Celts might have even less Stepp adm. than S England. The lower Steppe adm. there is probably just a function of a lack of Viking influence plus admixture with "old" (i.e. non-Viking influenced) Celts. In this scenario, the already admixed Norman-French (who, btw, were also present in Wales) did not make much of a difference.

Sgt said...

The authors allude to Roman influence ... The Driffield Terrace individual J2-L228/H5 {Levantine/SE-Euro} may be indicative of an early cosmopolitan influence in Britain.

Matt said...

Not sure why they didn't test f4 (Steppe, Neolithic Farmer; Northern England, Southern England) or f4 (Steppe, Neolithic Farmer; Celtic/Saxon, Northern England).

Although Cluster 2 (Blue - Southern England) is more southern than Cluster 4 (Purple - Northern England) on PC3, Cluster 2 actually seems to be very slightly less "southern" than Cluster 4 on PC1.

(Cluster 2 is also more slightly more clinal towards Cluster 5 (Orange - South Wales) on PC2. Slight Welsh related ancestry in the South English compared to North?)

dan said...

r1a farmers from middle east bring the wheat farming in india

Ned said...

I wonder.
My understanding was that with many DNA samples used for historical anthropological research the volunteers are asked to give the birthplaces of their parents and grandparents to weed the impact of recent migration out.
Biobank is different. I submitted to it and was asked if I objected to my DNA being used for medical research (I didn't). I was never asked about anthropological research and was not asked where my family hied from.
In the last 60 years there has been a large amount of inward migration into Britain, and although there are concentrations of immigrants, including second and third generation, in some Northern cities, most are concentrated in the South-East.
This may skew the bio-bank results compared to other DNA surveys.
Kind regards,

George said...

I am AA for rs601338 in FUT2.

Some say this SNP with AA means I, with my Northern European ancestry, am less susceptible to the stomach flu ... aka “viral gastroenteritis.”

However, very few people of Asian ancestry (ie Razib Khan) carry the resistant genetic variant. See also this map:

What does that tell a researcher about my earlier and ancient origins?

Does it mean my ancient ancestors had the opportunity for increased sex and more children since they had less flu?

Simon_W said...

Already the Viking Rollo who became the first duke of Normandy in 911 AD, married an indigenous "Frankish" Gallo-Roman wife, Poppa of Bayeux, and with him many of his men probably also mixed with the locals. That was many generations before 1066. But on another note, southeastern England was also affected by the continental, rather central European Urnfield and Hallstatt cultures and as the last wave before the Romans, by the Belgae. These later Celtic influences arguably were less steppe admixed than the first one before 2000 BC.

Average Joe said...

Is it possible that the lower Steppe ancestry could be due to the Roman occupation?

Unknown said...
This comment has been removed by the author.
Amanda S said...

It could be that this result reflects the inflow of people from Flanders and France in the several centuries after the Norman Conquest. Whilst the numbers coming as the direct consequence of the conquest is generally estimated as a low 2%, the number of people that came afterwards as economic migrants is unknown. France and Flanders were far more densely populated than England. I think there were some 15 million French compared to around 2 million English i by the 16th century. In the centuries after the conquest, the English towns grow and many new trades were introduced from the continent. The towns were a zone in which the highly Frenchified form of English that Middle English is could develop as English and French speakers met, worked and traded with one another.

Rob said...

This was already clear from the Davidski's plots on the ancient Hinxton Celtic samples and the Anglo Saxon samples as well as modern Scots and Irish all plotting with closer to steppe than modern SE English

Rob said...

I'll also add that the Norman invasion, which consisted of people from various parts of France, Normans (a mixture of Scandinavians, French, & Bretons}, Bretons and Flemish, was fairly small but for years after and into Angevin times there were more people moving to Britain from lands in France and Belgium.