Figure 2: Genome-wide picture of geographic variation.
From: Genome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls
a, P values for the 11-d.f. test for difference in SNP allele frequencies between geographical regions, within the 9 collections. SNPs have been excluded using the project quality control filters described in Methods. Green dots indicate SNPs with a P value <1 × 10-5. b, Quantile-quantile plots of these test statistics. SNPs at which the test statistic exceeds 100 are represented by triangles at the top of the plot, and the shaded region is the 95% concentration band (see Methods). Also shown in blue is the quantile-quantile plot resulting from removal of all SNPs in the 13 most differentiated regions (Table 1).