Table 3 Demographic and strength of selection parameter estimates obtained by fitting models with a single selection coefficient fitted (equal-effects model), a two-selection–coefficient model (two-effects model), and a model that assumes a gamma distribution of mutational effects to the inferred SFSs for zerofold and fourfold degenerate sites
ClassModelN2/N1t/N2bMean NesNes1Nes2p1ΔLogLΔAIC
ZerofoldEqual effects1.580.402.48601710
ZerofoldGamma2.310.520.144901222
ZerofoldTwo effects2.310.59210.0013330.3600
FourfoldEqual effects2.310.570.629.816
FourfoldGamma2.310.550.038200.80
FourfoldTwo effects2.310.562.80150.8200.4
  • We report estimates of the inferred change in population size (N2/N1, where N1 is the ancestral population size and N2 is the current population size), the inferred number of generations since the population size change in units of the current population size (t/N2), the inferred shape of the gamma distribution (b, where applicable), and the inferred mean scaled selection coefficient (Nes). For the two-effects model we also report the estimated scaled selection coefficient for each effects class (Nes1 and Nes2) and the proportion of mutations in the first class (p1). In the final columns we report the difference between the model’s log-likelihood and Akaike information criteria (AIC) from that of the best-fitting model for that data set (ΔLogL and ΔAIC, respectively).