Plots of the first and second PC of Y chromosome hg (Top), mtDNA hg (Middle), and X microsatellite (Bottom) allele frequency distributions. All Y hgs were included while the following common European mtDNA hgs were included: H, V, J, T, I, W, X, U3, U4, U5, and K. In the Y-chromosome data, the proportion of the variation explained by PC1 is 65% and that explained by PC2 is 28%, whereas in the mtDNA and X microsatellite data, these figures are 54% and 15%, and 46% and 33%, respectively.