"Genography" Puts European Ancestry on the Map

"Genography" Puts European Ancestry on the Map:

[Population geneticist John Novembre of the University of California, Los Angeles] and colleagues compared 500,000 SNP [single nucleotide polymorphism] differences among 1387 Europeans. To ensure that the people they examined had their roots firmly set in a certain region, the team looked at individuals whose grandparents hailed from the same region as they did. The scientists then employed a statistical technique known as principle component analysis, which allows large amounts of data with multiple variables to be condensed onto a two-dimensional space. Individual points were marked as two-letter abbreviations corresponding to the region of Europe to which each subject claimed ancestry (see image).

The result was a map of Europe — fuzzy, but unmistakable.

(Hat tip to Alex Tabarrok.)