Genotypes for 37,426,733 SNPs were imputed with IMPUTE219 using the genotyped SNPs and the 1000 Genomes reference panel released in June of 2011 (http://www.1000genomes.org/), which contains phased haplotypes for 1,094 individuals of various ancestries.20 EA and AA samples were imputed separately. We considered for analysis imputed SNPs with r2 greater than 0.8.
