The over-representation of participants of European ancestry in human genetics research has been broadly acknowledged1–5, and increasing the representation of diverse populations has recently become a higher priority for the research community5–10. This has led funding agencies such as the National Institutes of Mental Health to prioritize genetic studies of diverse populations. Accordingly, representation of non-European ancestry participants in genome-wide association studies (GWAS) increased, from 4% in 20091 to 19% in 20163. Most of the increase in non-European ancestry research is attributable to expansion of genetic studies of East Asian populations, as reported previously3 and as observed in our data (see below). Thus, most populations are still severely under-represented. This lack of representation, if not mitigated, will limit our understanding of etiological factors predisposing to disease risk, and will hinder efforts to develop precision medicine. It is also important to understand the implications of the European-centric bias of earlier genetic studies for work that builds upon existing research. For example, researchers need to know how the limited diversity in earlier medical genetic studies impacts the use of polygenic risk scores in non-European ancestry populations.
