The genetic history of Iceland

Razib has an excellent discussion of a brand new paper in PLoS Genetics, which uses DNA samples from medieval Icelandic skeletons to explore the genetic history of the Icelandic population.

This population is of course of great interest to human geneticists: the Icelandic company deCODE (the home of over half the authors on this paper) has used its exclusive access to the DNA and genealogical and health records of Icelanders to publish vast numbers of studies on the genetic basis of human disease and other complex traits. In addition, deCODE's consumer genetics division deCODEme provides one of the three mainstream personal genomics products currently on the market.

Part of the key to deCODE's success (in a scientific sense, not a financial one) is the relatively inbred nature of the Icelandic people. This results in greater genetic homogeneity and stronger linkage between neighbouring genetic variants, making it easier to spot the signals of association with disease. Razib's discussion of the evolutionary consequences of this long-term low population size is well worth a read.

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Agnar Helgason, Carles Lalueza-Fox, Shyamali Ghosh, Sigrún Sigurðardóttir, Maria Lourdes Sampietro, Elena Gigli, Adam Baker, Jaume Bertranpetit, Lilja Ãrnadóttir, Unnur Ãorsteinsdottir, Kári Stefánsson (2009). Sequences From First Settlers Reveal Rapid Evolution in Icelandic mtDNA Pool PLoS Genetics, 5 (1) DOI: 10.1371/journal.pgen.1000343

Image from here.