Estimation of the Multiple Testing Burden for Genomewide Association Studies of Common Variants

Genomewide association studies are an exciting strategy in genetics, recently becoming feasible. While pioneering studies are being underway, it is already clear that the analytic issue of determining the significance of results presents a challenge to the wide community of researchers. Rather than each study engaging in independent evaluation, there is need in the community to have standards set for whole-genome significance. We have therefore undertaken the task of developing such standards, based on data collected with collaborators in the International Haplotype Map Consortium. We report an estimated burden of a million independent tests genomewide in Europeans, and twice that number in Africans. We further identify the sensitivity of the testing burden to the required significance level, with implications to staged design of association studies.