be less predictive in the target population as compared with the discovery population, even when causal variants and their effect sizes are shared between ancestries. More generally, previous empirical and simulation studies have shown that accuracy of genetic predictors decays monotonically with increased genetic differentiation (FST) and LD differences between ancestries4,7,10. Other factors such as population specific causal variants11,12, gene × environment interaction13,14 have been implicated as potential explanations of the loss of PGS prediction accuracy.
