have estimated higher heritability for some quantitative traits than BBJ using the same methods, such as for height (h2 = 0.48±0.04 in Chinese women60). Some statistical fluctuations in the relative differences in prediction accuracy across populations are likely driven by differences in heritability measured in each population and/or trans-ethnic genetic correlation (i.e. of common variant effect sizes at SNPs common in two populations, Supplementary Figures 7–10, Supplementary Tables 2–5). These trans-ethnic correlation estimates indicate that effect sizes were mostly highly correlated across ancestries, with a few traits that were somewhat lower than excepted (e.g. height and BMI, with ρge=0.69 and 0.75, respectively). Prediction accuracy was far lower in individuals of African descent in the UK Bio bank (Supplementary Figures 4 and 11) using GWAS summary statistics from either European or Japanese ancestry individuals, consistent with reduced prediction accuracy with increasing genetic divergence (Figures 3 and 4). These population studies demonstrate the power and utility of increasingly diverse GWAS for prediction, especially in populations of non-European descent.
