Boundaries and clines in the West Eurasian Y-chromosome landscape: insights from the European part of Russia.

Previous studies of Y chromosome variation have revealed that western Europe, the Volga-Ural region, and the Caucasus differ dramatically with respect to Y-SNP haplogroup composition. The European part of Russia is situated in between these three regions; to determine if these differences reflect clines or boundaries in the Y-chromosome landscape, we analyzed 12 Y-SNPs in 545 males from 12 populations from the European part of Russia. The majority of Russian Y chromosomes (from 74% to 94%) belong to three Y chromosomal lineages [I-M170, R1a1-M17, and N3-TAT] that are also frequent in the rest of east Europe, north Europe, and/or in the Volga-Ural region. We find significant but low correlations between haplogroup frequencies and the geographic location of populations, suggesting gradual change in the Y chromosome gene pool across western Eurasia. However, we also find some significant boundaries between populations, suggesting that both isolation and migration have influenced the Y chromosome landscape.