Data contributed from South Africa were handled separately because the African ancestry panel used in SNPweights (YRI) is a West African sample. For the South African sample, the typical GWAS method of conducting principal components analysis (PCA), followed by visual inspection of data, was used. In doing so, we identified two populations, which are the two South African data sets in this report. For comparison of PGC-PTSD ancestry to previously published meta-analyses of psychiatric phenotypes see Figure 2a. Recent admixture is evident for AA and LA participants in this study (Figure 2b).
