Welsh Genetics: Abstracts and Summaries

by Kevin Alan Brook

Family Tree DNA - Genetic testing service
Family Tree DNA: Genetic Testing Service
DNA testing will show your connections with other families and ethnic groups. The database includes many peoples from throughout Europe and the rest of the world including Welsh, English, Irish, Cornish, Scots, and members of many other ethnic groups. The "Wales Cymru DNA Project" administered by Janet Crain and Susan Rosine invites the membership of all people who have one or both uniparental lines tracing back to Wales, Cornwall, and/or "English areas bordering present day Wales." There are many hundreds of participants and you can join them if you purchase a kit through Family Tree DNA and meet the project's eligibility requirement.

The Welsh are a proud remnant of many of the early inhabitants of the British Isles with a Celtic language quite unlike English. 19% of the people of Wales can speak Welsh, according to the 2011 census. Welsh is known for sometimes doubling the first letter of a word, as in ffordd (road) and llwyd (grey).

Bryan Sykes, professor of human genetics at the University of Oxford and founder of Oxford Ancestors, showed that people from North Wales and Mid-Wales are more genetically interlinked with each other than either are with people from South Wales. Sykes also found conclusive evidence that H is the dominant mitochondrial DNA (mtDNA) haplogroup in Wales.

Y-DNA haplogroups carried by members of "The Wales Cymru DNA Project" include E1b1a1 (E-L117), E1b1a1a1b1a (E-V13), E1b1a1b2a1a (E-M34), G1a1a1, G2a1, I1 (I-M253), I1d1a1a, I2c2a (I-M223, I-P37, etc.), J1, J2, R1a1a (R-M512, R-M198, R-M173, R-Z280), R1b1a (R-M269, R-M173, R-L21), and R1b1a1a1a1a (R-P312), among others. Mitochondrial DNA haplogroups carried by members include H, H3c2b, H1au1a, H10e, H6a1b2, H7b3, I, J, K1b2a2, K2a, T2, U3, U5, and others.

The SNP subclade Z138+ (also known as Z139+) of the Y-DNA haplogroup I1 is found at low frequencies in Germanic-speaking populations including England and Wales, but also in Portugal, southern Italy, and Romania. STR (short tandem repeats) analysis reveals a western subgroup of I1 where GATA-H4 ≥ 11 that's most common in Wales that exists at lower frequencies in English and other European populations.

Major studies of the Welsh

Michael E. Weale, Deborah A. Weiss, Rolf F. Jager, Neil Bradman, and Mark G. Thomas. "Y Chromosome Evidence for Anglo-Saxon Mass Migration." Molecular Biology and Evolution 19:7 (2002): pages 1008-1021.
      They studied English, Welsh, Norwegian, and Frisian men and genetically compared them to each other. Samples included males from 2 towns in North Wales (Abergele and Llangefni) and 5 towns in England as far east as North Walsham in East Anglia. The sampled men from Central English towns genetically resembled each other closely, in contrast to the North Welsh men who "differed significantly both from each other and from the Central English towns." They found common Germanic roots of the English and Frisian males in the study, confirming that the Anglo-Saxons (but not the Welsh) are largely descended from people not indigenous to the British Isles. Excerpts from the article:

"Our results indicate the presence of a strong genetic barrier between Central England and North Wales and the virtual absence of a barrier between Central England and Friesland. [...] The best explanation for our findings is that the Anglo-Saxon cultural transition in Central England coincided with a mass immigration from the continent. Such an event would simultaneously explain both the high Central English-Frisian affinity and the low Central English-North Welsh affinity. [...] Anglo-Saxon settlements and culture appeared throughout England but, importantly, did not extend into North Wales, where many of the original Celtic Britons living in England are thought to have fled [...]"

Fulvio Cruciani, Roberta La Fratta, Beniamino Trombetta, Piero Santolamazza, Daniele Sellitto, Eliane Beraud Colomb, Jean-Michel Dugoujon, Federica Crivellaro, Tamara Benincasa, Roberto Pascone, Pedro Moral, Elizabeth Watson, Bela Melegh, Guido Barbujani, Silvia Fuselli, Giuseppe Vona, Boris Zagradisnik, Guenter Assum, Radim Brdicka, Andrey I. Kozlov, Georgi D. Efremov, Alfredo Coppa, Andrea Novelletto, and Rosaria Scozzari. "Tracing Past Human Male Movements in Northern/Eastern Africa and Western Eurasia: New Clues from Y-Chromosomal Haplogroups E-M78 and J-M12." Molecular Biology and Evolution 24:6 (2007): 1300-1311. First published online on March 10, 2007.
      33 percent of men who live in the town of Abergele in North Wales have the Y-DNA haplogroup E1b1b1, probably from migrations from the Balkans. The sample size was 18.

"'Extraordinary' genetic make-up of north east Wales men." BBC News (July 19, 2011).
      Dr. Andy Grierson of the University of Sheffield comments on the finding of E1b1b1 in a large percentage (the article states approximately 30 percent) of men from northeast Wales (the town of Abergele). (Most of the men specifically carry E1b1b1a2, also known as E-V13). This is found in a much higher frequency than populations in the rest of the United Kingdom, which average 1 percent. The sample size was 500 people. Grierson said, "This type of genetic makeup is usually found in the eastern Mediterranean which made us think that there might have been strong connections between north east Wales and this part of Europe somewhere in the past. But this appears not to be the case, so we're still looking to find out why it's happened and what it reveals about the history of the region."

Stephen Leslie, Bruce Winney, Garrett Hellenthal, Dan Davison, Abdelhamid Boumertit, Tammy Day, Katarzyna Hutnik, Ellen C. Royrvik, Barry Cunliffe, Wellcome Trust Case Control Consortium, International Multiple Sclerosis Genetics Consortium, Daniel J. Lawson, Daniel Falush, Colin Freeman, Matti Pirinen, Simon Myers, Mark Robinson, Peter Donnelly, and Walter Bodmer. "The fine-scale genetic structure of the British population." Nature 519 (March 19, 2015): pages 309-314. First published online on March 18, 2015.
      Welsh form part of this intensive evaluation of autosomal DNA. Excerpts from the Abstract:

"[...] We use haplotype-based statistical methods to analyse genome-wide single nucleotide polymorphism (SNP) data from a carefully chosen geographically diverse sample of 2,039 individuals from the United Kingdom. [...] The regional genetic differentiation and differing patterns of shared ancestry with 6,209 individuals from across Europe carry clear signals of historical demographic events. [...] in non-Saxon parts of the United Kingdom, there exist genetically differentiated subgroups rather than a general 'Celtic' population."

Steve Connor. "New genetic map of Britain shows successive waves of immigration going back 10,000 years." The Independent (March 18, 2015).
      This article about the study published in March 2015 by Stephen Leslie, Peter Donnelly, and their colleagues points out "the ancient ancestry of the Celtic people of North Wales who are probably descended from some of the oldest inhabitants of Britain".

Harriet Cooke. "Welsh and Cornish are the 'purest Britons', scientists claim." Telegraph.co.uk (June 17, 2012).
      A team including Peter Donnelly, professor of statistical science at Oxford University and director of the Wellcome Trust centre for human genetics, has used samples gathered from about 2,000 "rural dwellers" from across the United Kingdom who "had to have four grandparents born in the same area" and discovered that Welsh people have genetics similar to Irish and French people, which is suggestive of their descent from pre-Roman peoples who moved to the British Isles thousands of years before the arrival of Germanic speakers of early English. Cornish people from Cornwall, too, are distinct from the English people who inhabit the neighboring county of Devon. As Donnelly succintly put it, "The people of Wales and Cornwall are different from the rest of southern and central England." The results were presented in July 2012 at the Royal Society's summer science exhibition in London.

"Welsh people could be most ancient in UK, DNA suggests." BBC News (June 19, 2012).
      This is another article about Professor Donnelly's team's research. Excerpts from the article:

"[...] DNA samples were analysed at about 500,000 different points. After comparing statistics, a map was compiled which showed Wales and Cornwall stood out. Prof Donnelly said: 'People from Wales are genetically relatively distinct, they look different genetically from much of the rest of mainland Britain, and actually people in north Wales look relatively distinct from people in south Wales.' While there were traces of migrant groups across the UK, there were fewer in Wales and Cornwall. He said people from south and north Wales genetically have 'fairly large similarities with the ancestry of people from Ireland on the one hand and France on the other, which we think is most likely to be a combination of remnants of very ancient populations who moved across into Britain after the last Ice Age. [...]' He said it was possible that people came over from Ireland to north Wales because it was the closest point, and the same for people coming to south Wales from the continent, as it was nearer. However he added: 'We don't really have the historical evidence about what those genetic inputs were.' [...] Because of its westerly position and mountainous nature, Anglo-Saxons who moved into central and eastern England after the Romans left did not come that far west, and neither did the Vikings who arrived in around 900AD. [...] The mountains were also the reason why [Welsh] DNA may have remained relatively unchanged, as people would have found it harder to get from north to south Wales or into England compared with people trying to move across the flatter southern English counties, making them more likely to marry locally and conserve more ancient DNA. [...]"

Helen McArdle. "DNA links Welsh men to Scotland." Herald Scotland (November 24, 2014).
      The team of Alistair Moffat of CymruDNAWales and Scotland's DNA discovered that 1 percent of Welsh males carry a Y chromosome variety that descends from ancient Picts from Scotland and is related to the modern Scottish variety of this lineage. Excerpts from the article:

"Some 10 per cent of all Scottish men belong to this 'Pictish' lineage compared to just 0.8 per cent of Englishmen. It is particularly concentrated in Perthshire, Fife, Angus and Grampian, regions of Scotland with known Pictish heritage. The discovery of shared ancestral ties between men in Scotland and Wales is at the centre of a new theory that this one per cent of Welsh men are direct descendents of a small band of ancient Scottish aristocrats, who fled the Old Welsh-speaking kingdom of Strathclyde in the ninth century to escape a Viking invasion. They are thought to have headed south, by sea, to find refuge in north Wales after the Viking kings Ivar and Olaf led their dragonships up the Clyde in 870, laying siege to the fortress on Dumbarton Rock and eventually capturing Artgul, the king of Strathclyde."

Nathan Bevan. "DNA survey reveals 25% of Welsh men directly descended from ancient kings and warlords." Wales Online (December 18, 2014).
      Alistair Moffat of CymruDNAWales is interviewed as saying 25 percent of Welsh men whose grandparents were all Welsh inherited their Y chromosomes from about 20 medieval Welsh royals, nobles, and warlords who had many descendants. Moffat also spoke about what the team learned so far about the earliest immigrants to Wales, thousands of years ago. He said, "We all suspected that Wales was a Celtic country but no-one was prepared for just how much - the classic Celtic Y chromosome marker R1b S145 being carried by a whopping 45% of Welsh men, as opposed to just 15% over on the other side of Offa's Dyke. We have always known that Wales is different from England, but now here is a statistic that shows there is no question about it."

Nathan Bevan. "Welsh presenter Angharad Mair digs up her DNA roots in the Eastern Mediterranean." Wales Online (January 17, 2015).
      The Welsh television presenter Angharad Mair had her DNA tested by CymruDNAWales. Upon examining her mitochrodrial DNA, they found that her maternal lineage came from the Levant region (eastern Mediterranean) thousands of years ago. Excerpts:

"[...] These particular mitochrodrial DNA markers [...] appear with very high frequency in Wales - at around 11%. They are thought to have been brought to Britain and Ireland by roaming bands of hunter-gatherers over many millennia and, after 3,000BC, by the first female farmers from the Fertile Crescent region of Western Asia. However, they are most commonly found among Ashkenazi Jews of Europe, where a third of all maternal bloodlines are Levantine. [...] 'I was very excited to discover that I had Jewish ancestry - which might've only developed in the last two centuries.' [...]"


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  • A History of Wales by John Davies: English edition, Welsh edition
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  • The Rough Guide to Wales
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  • Genetics of Cornish People
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