Table 1. Models of background selection with selection on nonsynonymous, weakly selected, and strongly selected noncoding sites.

Model 1	Standard mapping function with summation over all sites and integration over the distributions of selection coefficients
Model 2	Linear mapping function with summation over all sites and integration over the distributions of selection coefficients
Model 3	Approximations using integration over a continuum of sites (with a linear mapping function)
Model 4	Approximations using summation of the integrals over each cluster of sites with the same selection regime (with a linear mapping function) and integration over the distributions of selection coefficients
Model 5	Approximations using integration along the genome of the integrals over clusters of sites (with a linear mapping function), and first and second moments of the distributions of selection coefficients