At left is a principle component analysis of European genetic variability as described in a recent paper by Carlos Bustamenta et al. in the British journal Nature. The paper describes the genotyping of 3,192 Europeans at 500,568 single nucleotide (SNP) polymorphisms using the Affymetrix 500K chip. The authors say that they focused on 197,146 SNPs from 1,387 individuals that met their criteria of high confidence that included having four grandparents born nearby the location in Europe sampled.
The principle component analysis looks very much like the map of Europe, suggesting more population structure than may have been previously appreciated. It remains to be seen if these kinds of analyzes will be useful for families that left Europe between three and four hundred years ago. Only time will tell if we can say with some certainty that this part of this chromosome came from England, this part from France, this from Spain, etc.
Ref: Carlos D. Bustamente et al., a letter in Nature doi:10.1038/nature07331, 2008; listen to an interview with two of the authors featured on the Nature: 04 Sep 2008 podcast, skip to 1:20 to begin the segment.
