Fig. 4.—
(A) Effect on dN/dS of changing the fraction of mutations that are deleterious (
), computed using a simple model, where the effect of the mutation on the free energy of folding is equal to 
(blue), 
(red), 
(green), 
(purple), and 
(orange). Other parameters as defined in the text. (B) Effect on dN/dS of changing the fraction of mutations that are advantageous (
), computed using a simple model, where the effect of the mutation on the free energy of folding is equal to 
(blue), 
(red), 
(green), 
(purple), and 
(orange). Other parameters as defined in the text.