Genetic differences larger between populations in Northern Europe

[PRESS RELEASE, 24 October 2008] Researchers at Karolinska Institutet and Helsinki University have shown that the genetic differences appear larger between the populations in Northern Europe than within Central Europe. The genetic distance is especially notable between Eastern and Western Finland. The study is published in the science journal PLoS One and is important for the understanding of genetic factors behind human diseases.

Juha KerePhoto: Jacob Forsell

 When studying diseases and new treatments, it is important to match the studied group with a similar control group. Otherwise the results could be overestimated, when they in fact just shows normal differences between for instance different part of a country, says Professor Juha Kere at Karolinska Institutet in Stockholm.

Human population genetic studies have recently gained a new powerful tool from the analysis of densely spaced single nucleotide polymorphisms (SNPs) across the whole genome. In this study, almost 250 000 such polymorphisms were used to analyze genetic differences between the Germans, British, Eastern and Western Finns and Swedes.

The Germans and British are genetically close to each other, which also have been observed in other recently published studies. The genetic distances between the Swedes and Finns are somewhat larger. The researchers also found that the genetic difference between Eastern and Western Finland was substantial in a European scale. Even between Finnish counties there were clear differences.

 The larger genetic distances in the north are caused by differences in population history. The northernmost parts of Europe were inhabited later than Central Europe and by fewer people, and have had smaller populations since then, says Päivi Lahermo, research team leader at Helsinki University.

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