Figure 5.

Joint distribution of $\Delta G$ of folding and the additive contribution to $\Delta G$ of folding for the independent epistasis model with ${\sigma }_{\mathrm{HOC}}^2$ chosen so that the bivariate normal approximation matches the bivariate normal approximation shown in Figure 1g. Simulations conducted under the independent epistasis model with ${\mu }_{\mathrm{add}}=1\mathrm{kcal}/\mathrm{mol}$, ${\sigma }_{\mathrm{add}}^2=1{\mathrm{kcal}}^2/{\mathrm{mol}}^2$, ${\sigma }_{\mathrm{HOC}}^2=21.6{\mathrm{kcal}}^2/{\mathrm{mol}}^2$. A dashed curve shows the area predicted to include 95% of sequences at stationarity under the bivariate normal approximation; the dashed vertical line at $\Delta G_{\mathrm{add}}=18.8$ reflects a value, derived using a crude percolation theory argument, for the right-most edge of the region where the bivariate normal approximation is expected to be valid.