Given the requirement for historically large sample sizes, it has become typical for primary studies to band together to form meta-analytic consortia. This has proven to be a crucially important step in achieving sufficient statistical power. For example, two primary type 2 diabetes mellitus GWAS were completely unremarkable individually and yet, after meta-analysis, multiple highly significant and replicated findings emerged (Saxena et al., 2007, Scott et al., 2007).
