Fig. 3.

Statistics of mutations. (a) Lengths of mutant proteins that cause a decreased ligand-binding affinity or an increased one. (b) Organisms where the proteins belong. (c) The density of the mutations inducing an absolute affinity fold change ($\left|\mathit{fc}\right|$) larger or equal to a threshold (t). Results for $t=1.05,t=1.2,t=2$ and $t=3.6$ have been further marked.