Some population genetics from the University of California have created a map of European populations with the genome of 1,387 European inhabitants comparing small parts of these genomes, based on the differences called mononucleotide polymorphisms. It can be observed that it is quite similar to the European geographical map, overlapping each other.
A good result is that the distribution map obtained through the genes, known as the genographic map, is very similar, but it is also normal to do so. In short, a citizen of a country is more likely to meet with someone from his country and have children than to do with someone from abroad (among other things because they speak in the same language).