Fig. 4

P-values for average risk allele frequency regressed on environment. P-values are calculated by comparing the R² of the disease risk allele frequencies to a null distribution created using 10,000 resampled sets of SNPs matched for number of and global allele frequency of disease risk SNPs. * Indicates significance after adjustment for an FDR of 0.2. + Indicates significance after Bonferroni correction (see “Null Distributions” section in Methods)