Our simulation study considered four different scenarios of genetic architecture at the locus, focusing only on the effect of LD, sample sizes, and admixture proportions, and assuming that effect sizes were the same across populations. Details are provided in the Supplementary Material. For each choice of causal SNP(s) we repeated the simulation 500 times, constructing 12 PRSs each time (all combinations of the four selection and three weight estimation approaches), and we recorded the median RMSPE for each PRS across the 500 repetitions.
