We performed imputation with a reference panel from the October 2011 release of the 1000 Genomes Project by using BEAGLE version 3.3.1. Both SNPs were genotyped on the Illumina Metabochip and 1M-Duo, rs1800562 was genotyped on the Illumina 660W, and rs1799945 was genotyped on the Illumina OMNI. For all other genotyping platforms, the imputed genotypes for the SNPs were used. Directly genotyped SNPs and imputed SNPs are summarized by site in Table S1.