Using a slightly modified version of the SNP selection algorithm described in the Material and Methods Section, from the list of 475,116 testing SNPs monitored by the Illumina HumanHap550 chip, we identified a new second set of 7,017 structure inference SNPs that are locally uncorrelated (r 2 less than 0.004 for any pair located less than 500 kb apart on the same chromosome) among themselves and similarly uncorrelated to the 12,898 SNPs already identified. The dependence of the PCA conclusions on the set of structure inference SNPs can be evaluated by comparing the results using the first set of 12,898 SNPs to those obtained with the second set of 7,017 SNPs
