Ancient Roots

Ancient Roots

What does it mean to have Celtic ancestry? How thorough was the Anglo-Saxon invasion? These are some of the questions that are being answered by a major DNA research project

DNA, DNA

DNA

DNA


Map of the UK showing clustering of individuals based on genetics
Map of the UK showing clustering of individuals based on genetics, and its striking relationship with geography. Each of the genetic clusters is represented by a different symbol (combining shape and colour, with legend at the sides). There is one symbol plotted on the map for each of the individuals in the study. The ellipses give a sense of the geographical range of each genetic cluster. Image produced by Stephen Leslie/Nature. Contains OS data © Crown copyright and database right 2012. © EuroGeographics for some administrative boundaries

Many people in the UK feel a strong sense of regional identity, and it now appears that there may be a scientific basis to this feeling, according to a landmark new study into the genetic makeup of the British Isles.

An international team, led by researchers from the University of Oxford, UCL (University College London) and the Murdoch Childrens Research Institute in Australia, used DNA samples collected from more than 2,000 people to create the first fine-scale genetic map of any country in the world. Their findings, published in Nature in a paper entitled ‘The fine-scale genetic structure of the British population’, show that prior to the mass migrations of the 20th century there was a striking pattern of rich but subtle genetic variation across the UK, with distinct groups of genetically similar individuals clustered together geographically.

By comparing this information with DNA samples from over 6,000 Europeans, the team was also able to identify clear traces of the population movements into the UK over the past 10,000 years. Their work confirmed, and in many cases shed further light on, known historical migration patterns.

Dr Stephen Leslie, of Murdoch Childrens Research Institute in Australia, and one of the lead authors of the study, said: Rich genetic information such as this tells us a great deal about our history and augments what we know already from archaeology, linguistic and historical records. Much of what we’ve learned about our history comes from the successful people of society, as they leave the strongest marks on history and archaeology. By using genetics and powerful statistical methods, we have been able to tell the story of the masses.

Many of the genetic clusters show similar locations to the tribal groupings and kingdoms around the 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.

Professor Mark Robinson, an archaeologist on the project from the Oxford University Museum of Natural History, said: The results give an answer to the question we had never previously thought we would be able to ask about the degree of British survival after the collapse of Roman Britain and the coming of the Saxons.

The Wellcome Trust-funded People of the British Isles study (www.peopleofthebritishisles.org) analysed the DNA of 2,039 people from rural areas of the UK, whose four grandparents were all born within 50 miles of each other. Because a quarter of our genome comes from each of our grandparents, the researchers were effectively sampling DNA from these ancestors, allowing a snapshot of UK genetics in the late 19th century. They also analysed data from 6,209 individuals from ten modern European countries.

Professor Simon Myers, from the University of Oxford, who co-led the development of the statistical approaches used in the study, said: In future, increasingly large datasets will allow us to learn even more about the genetic history of the UK, and the similarly rich histories of other world regions, by applying similar techniques.

To uncover the extremely subtle genetic differences among these individuals the researchers used cutting-edge statistical techniques, developed by four of the team members. They applied these methods, called ‘fineSTRUCTURE’ and ‘GLOBETROTTER’, to analyse DNA differences at more than 500,000 positions within the genome. They then separated the samples into groups of genetically similar individuals, without knowing where in the UK the samples came from. By plotting each person onto a map of the British Isles, using the centrepoint of their grandparents’ birth places, they were able to see how this distribution correlated with their genetic groupings.

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Routes taken by the first settlers after the last ice age
Major events in the peopling of the British Isles: a: the routes taken by the first settlers after the last ice age; b: Britain during the period of Roman rule; c: the regions of ancient British, Irish and Saxon control; d: the migrations of Norse and Danish Vikings. The main regions of Norse Viking (light brown) and Danish Viking (light blue) settlement are shown. Image produced by Stephen Leslie/Nature. Contains OS data © Crown copyright and database right 2012. © EuroGeographics for some administrative boundaries

The researchers were then able to ‘zoom in’ to examine the genetic patterns in the UK at levels of increasing resolution. At the broadest scale, the population in Orkney (islands to the north of Scotland) emerged as the most genetically distinct. At the next level, Wales forms a distinct genetic group, followed by a further division between north and south Wales. Then the north of England, Scotland, and Northern Ireland collectively separate from southern England, before Cornwall forms a separate cluster. Scotland and Northern Ireland then separate from northern England. The study eventually focused at the level where the UK was divided into 17 genetically distinct clusters of people.

Dr Michael Dunn, Head of Genetics & Molecular Sciences at the Wellcome Trust, said: These researchers have been able to use modern genetic techniques to provide answers to the centuries-old question – where we come from. 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.

In the print edition
Read about how DNA can help find lost members of your family tree, in Issue 4 of Discover Your Ancestors, available online at discoveryourancestors.co.uk

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