Estimates from Ancestry Composition are extremely well calibrated, with correlations of African, European, and Native American ancestry estimates showing r2 > 0.98 with 1000 Genomes Project African American and Latino consensus estimates (Figure 5 from Durand et al.33). Admixture tests via an independent admixture software package, ADMIXTOOLS,64 confirm significant signals of African admixture in European Americans (Table S7). Ancestry Composition estimates are highly concordant with ADMIXTURE66 estimates, with r2 values of 0.94, 0.98, and 0.91, for the three groups, respectively (Figure S14).