To define the prior for each causal configuration, we use a general discrete distribution for the number of causal SNPs pk=Pr(#of causal SNPs isk), k=1,…,K, where K<<m is the maximum number of SNPs in the causal configuration. Note that we assume that the region to be fine-mapped includes at least one causal SNP, i.e. p0=0. For a fixed value of k, we assume the same probability for each configuration with k causal SNPs. Thus, a priori, p(γ)=pk/(mk) when∑ℓ=1mγℓ=k.
