Tuesday, 10 July 2012

People of the British Isles

The University of Oxford's "People of the British Isles" project were part of the the Royal Society's Summer Exhibition recently, in which they described the work they had been doing to map the genetic diversity of the British Isles.

The PoBI project has coolected DNA samples from some 3,000 volunteers in rural populations around the UK. The names and DNA characteristics of these volunteers are being used to build a map showing how ancestry varies across the UK.

For example,it is known two important sources of historical genetic information are the Y chromosome, which is passed on by fathers, and mitochondrial DNA, which is passed on by mothers. The DNA of people in the Orkneys shows a relaitvely high proportiion of a particular Y type that is common in Scandanavia, but mitochondria DNA that is similar to rest of the UK. This suggests that male Vikings raided the islands but then settled there and married Orkney women.

Whilst this is very interesting, the main motivation behind the project is to determine whether particular diseases can be associated with particular DNA sequences.

In the early days of DNA testing, back in the 60s and 70s, two groups of people (one with a disease, one without) would be compared to see if there were significant differences between them.

Initially there were some successes (such as certain types of arthritis). However, when a similar approach was taked with more complex conditions such as heart disease (where a number of genes may be involved) results were much less conclusive. The small sample sizes of these studies also made it hard to draw firm conclusions.

So, it seems that what is needed is large studies and a fine grained understanding of genetic diversity in the UK.

It is this latter point that the project focusses on.

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