Population amd Disease Genetics Group Centre for Population Health Sciences
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Population Structure

Human genetic variation is not distributed randomly across the world, because we do not mate randomly, humans have always tended to marry within their community. We study how genetic variants are distributed across individuals and populations – which populations are similar genetically and which differ, how individuals are related genetically, and where differences lie. The pattern of sharing of DNA variants is called population genetic structure and reveals information about the history of the populations. Population structuring is also medically significant, influencing disease risk in different populations, their response to drugs, as well as being important in the design of studies searching for the genes underlying common diseases.

Our recently published studies have analysed the population structure between Britain and Ireland, and the very fine scale differentiation among rural villages in Europe. The first revealed small differences between England and Ireland, with the genetic variation in Scotland being intermediate between these, but with a subtle ancestry component of its own. Scotland and Ireland are also noticeably less diverse than England, being at the extreme of the great decline in genetic diversity from the Near East to the north-west of the continent.

The second zoomed in from the level of countries down to villages and by analysing three groups of nearby settlements – in Croatia, Italy and Scotland – showed that it is possible using genetic data alone to predict the village from which a person originated. The accuracy of prediction was very high, reaching 100% in the Italian Alps, and was 89% for two villages separated by only 5 miles in Croatia! It is likely that this kind of fine-scale genetic structuring is common across much of rural Europe and possibly other parts of the Old World.

 


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