New Study Examines Genetic Structure of British Population Mar 19, 2015 by Sci-News.com
In a new study published in the journal Nature, scientists used DNA samples collected from 2,039 people to create the fine-scale genetic map of British Isles.
The team, led by Dr Peter Donnelly of the Wellcome Trust Centre for Human Genetics in Oxford, UK, analyzed the DNA of people from rural areas of the UK, whose four grandparents were all born within 80 km of each other.
Because a quarter of our genome comes from each of our grandparents, Dr Donnelly and his colleagues were effectively sampling DNA from these ancestors, allowing a snapshot of UK genetics in the late 19th century.
The scientists found that the samples could be grouped into 17 clusters, which coincided strongly with geographical areas.
They then went on to compare each cluster’s DNA with samples from 6,209 people in ten European countries with a history of migration to the British Isles.
The results confirm that successive waves of invaders never wiped out the existing populations but interbred with them.
According to the scientists, “the majority of eastern, central and southern England is made up of a single, relatively homogeneous, genetic group with a significant DNA contribution from Anglo-Saxon migrations (10-40 percent of total ancestry). This settles a historical controversy in showing that the Anglo-Saxons intermarried with, rather than replaced, the existing populations.”
“There are separate genetic groups in Cornwall and Devon, with a division almost exactly along the modern county boundary.”
“The population in Orkney emerged as the most genetically distinct, with 25 percent of DNA coming from Norwegian ancestors. This shows clearly that the Norse Viking invasion (9th century) did not simply replace the indigenous Orkney population.”
There is no obvious genetic signature of the Danish Vikings, who controlled large parts of England from the 9th century.
“The Welsh appear more similar to the earliest settlers of Britain after the last ice age than do other people in the UK.
The scientists said there was not a single Celtic genetic group. “In fact the Celtic parts of the UK (Scotland, Northern Ireland, Wales and Cornwall) are among the most different from each other genetically. For example, the Cornish are much more similar genetically to other English groups than they are to the Welsh or the Scots.”
“There is genetic evidence of the effect of the Landsker line – the boundary between English-speaking people in south-west Pembrokeshire and the Welsh speakers in the rest of Wales, which persisted for almost a millennium.”
The study suggests there was a substantial migration across the channel after the original post-Ice-Age settlers, but before Roman times.
“DNA from these migrants spread across England, Scotland, and Northern Ireland, but had little impact in Wales.”
“Many of the genetic clusters show similar locations to the tribal groupings and kingdoms around end of the 6th century, after the settlement of the Anglo-Saxons, suggesting these tribes and kingdoms may have maintained a regional identity for many centuries.”
“Beyond the fascinating insights into our history, this information could prove very useful from a health perspective, as building a picture of population genetics at this scale may in future help us to design better genetic studies to investigate disease,” said Dr Michael Dunn of the Wellcome Trust Centre for Human Genetics.
The fine-scale genetic structure of the British population
Stephen Leslie et al.
Stephen Leslie et al.
Fine-scale genetic variation between human populations is interesting as a signature of historical demographic events and because of its potential for confounding disease studies. 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. This reveals a rich and detailed pattern of genetic differentiation with remarkable concordance between genetic clusters and geography. The regional genetic differentiation and differing patterns of shared ancestry with 6,209 individuals from across Europe carry clear signals of historical demographic events. We estimate the genetic contribution to southeastern England from Anglo-Saxon migrations to be under half, and identify the regions not carrying genetic material from these migrations. We suggest significant pre-Roman but post-Mesolithic movement into southeastern England from continental Europe, and show that in non-Saxon parts of the United Kingdom, there exist genetically differentiated subgroups rather than a general ‘Celtic’ population.
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So what is your opinion on the paper? What are your observations?
quote: Because a quarter of our genome comes from each of our grandparents, Dr Donnelly and his colleagues were effectively sampling DNA from these ancestors, allowing a snapshot of UK genetics in the late 19th century.
quote: There is no obvious genetic signature of the Danish Vikings, who controlled large parts of England from the 9th century.
Logically, since Vikings took populations enslaved populations from elsewhere and brought them the England. Mostly Balts.
And of course there has been a genetic drift and bottle neck effect of incoming popuations to the already existing populations.
quote: “DNA from these migrants spread across England, Scotland, and Northern Ireland, but had little impact in Wales.”
Lioness, so then what happened to these incoming populations and people? Who were they? Besides Wales?
quote: We suggest significant pre-Roman but post-Mesolithic movement into southeastern England from continental Europe, and show that in non-Saxon parts of the United Kingdom, there exist genetically differentiated subgroups rather than a general ‘Celtic’ population.
Lioness, what could this suggest?
Extended Data Figure 1: The effect of setting a threshold on the confidence of cluster assignment for the genetic clusters in the UK inferred by the fineSTRUCTURE analysis.
Extended Data Figure 8: Application of GLOBETROTTER to infer simulation of ancestry 40 generations ago between groups from Northern Germany (GER3, 25%) and Italy (ITA36, 75%).
quote: Slavery was an institution of the Roman Empire, and picked by the Germanic tribes who dealt with it, as victims or suppliers. When those Germanic tribes reached Britain in the 5th century, they brought the practice with them, and the complete disappearance of Celtic culture from the east and south-east of Britain is strong evidence for their success. The chronicler Gildas was probably correct when he claimed that slavery was a common fate for many of his contemporaries, as the story of St. Patrick demonstrates. He was captured by pirates in the south-west of England, and spent six years in Ireland before escaping.
--Pelteret, D, 'Slave raiding and slave trading in early England', Anglo-Saxon England 9 (1981), pp99-114
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