cost-effective strategy to obtain the large number of control subjects needed for GWAS analyses, which may be particularly beneficial for ancestry groups with fewer available samples (e.g., African Americans) (Hartz et al. 2011). However, publicly available GWAS differ in many respects, including use of a wide variety of high-density genotyping arrays. Thus, one of the substantial challenges such studies face is creating a common set of single nucleotide polymorphisms (SNPs) across studies contributing to composite controls and study cases.
