A specialist, having obtained a genetic sample from a native inhabitant of any European country, is able to determine his homeland with an accuracy of up to several hundred kilometers. Such conclusions were reached by a group of geneticists from Switzerland and the USA, who attempted to compile a 'genogeographic' map of the Old World. The scientists had at their disposal a database of 3,200 DNA samples collected in several countries of Western and Central Europe. They selected specifically native inhabitants of particular territories (it is clear that migrants could introduce any distortions into the map). The degree of 'nativity' was determined over two generations: the grandparents of the owner of the analyzed DNA had to have lived in the same region.
Carlos Bustamante from Cornell University noted that the technique of tracking minor nucleotide changes in DNA made it possible to determine with very high accuracy in which part of Europe a given sample was taken. In particular, according to John Novembre from the University of California, Los Angeles, when compiling the map, it was easy to distinguish the Iberian Peninsula (Spain and Portugal), Italy, Southeastern Europe, Turkey, and Cyprus. Interestingly, the genetic data of the Swiss, who have lived in the same country for many hundreds of years, have still not mixed. The DNA of residents of German-speaking cantons is similar to the genome of Germans, the French west of the confederation corresponds on the map to France, and the Italian part of the country is genetically close to the Apennines.
The place of residence of a person from whom a genome sample is taken can be localized quite accurately if sufficient information is available. For example, in countries well mapped by geneticists, the accuracy of the prediction can increase to three hundred kilometers (thus it is possible to determine the 'residence' of the owners of half of the studied DNA). But even if we take Europe as a whole (according to the scheme, without the East Slavic states), the probability of correct determination does not drop too much. In this case, 50% of genomes are localized with an accuracy of up to 540 km, and if we take 90% of all samples, it is possible to determine the place of residence with an accuracy of up to 840 km.
Of course, one can be very skeptical about such genetic orientation, since Europe is still not a very significant part of the world in terms of area. 840 kilometers is actually the size of a very large country, of which there are fewer and fewer. Indeed, in terms of size, the average European 'power' in recent decades has persistently striven to reach the Liechtenstein-Luxembourg level. Nevertheless, for those countries that have not yet disintegrated into atoms, such accuracy is still quite sufficient.