History and geography of human Y-chromosome in Europe: a SNP perspective.

The genetic variation observed in the modern European populations can be used to reconstruct the history of the human peopling of the continent. In recent times, a great importance has been given to uniparental markers such as the Y-chromosome. This chromosome, which is passed from father to son, does not have a counterpart subject to recombination and the only possible source of variation is mutation. The nucleotide changes accumulate over time in the molecule, with no rearrangement among lineages. Lately, the D-HPLC technique, which allows the effective detection of single nucleotide polymorphisms (SNPs), was used to boost the number of available polymorphisms on the Y-chromosome. Since the year 2000, a number of studies were aimed both at the reconstruction of Y-chromosome phylogeny and the geographic distribution of Y-chromosome variation in Europe. The distribution of distinctive Y-chromosome lineages can also display a correspondence with geography, thus providing patterns of affinity and clues concerning past human movements. It is therefore possible to recognize the effect of the colonization of Europe following the Last Glacial Maximum, both from the western Iberian and the eastern Balkan refuges. Other lineages show a migratory wave from the Near East, consistent with the demic diffusion model of agriculture. A minor east-west genetic cline was proposed as a signal of an expansion from north of the Black Sea, related with the diffusion of people speaking languages of the Indo-European family.