We imputed all SNPs reported in the CEU sample in HapMap Phase II using various imputation algorithms12,37 (see the URL section for a link to the software ProbABEL). Imputations were performed after excluding samples and SNPs that did not meet the study-specific quality control criteria. Genotypes were imputed for SNPs not present in the genome-wide arrays or for those where genotyping had failed to meet the QC criteria.
