It is estimated that an overwhelming proportion of participants in existing GWAS are of European ancestry.17,18 Data generated from GWAS of individuals of European ancestry are less applicable to other ancestral groups and when applied to non-European cohorts may result in inaccurate estimations of risk that may further perpetuate racial health and healthcare disparities. Studies suggest that even when discovery samples of non-European individuals are small, including them in individual discovery analyses and trans-ancestral analyses can result in novel insights into the genetic architecture of the disorder and in polygenic prediction12,19,20. Differences in prevalence and patterns of substance dependence across ancestrally diverse groups in the United States21 underscore the importance of conducting GWAS on these phenotypes in these groups. In particular, the study of African-Americans, one the largest minorities represented in GWAS data in the US, provides an opportunity to address this notable disparity in genomic research.
