Table 3 Substitutions of amino acid x→ y

Adaptation M→P:

$N_{x,y}^{(M,P)}$

89

$N_{x,non-y}^{(M,P)}$

1754

Background M→M:

$N_{x,y}^{(M,M)}$

14

$N_{x,non-y}^{(M,M)}$

514