Frequency of appearance of amino acids in beta-lactamase dataset.

The amino acid distribution is plotted for the functionally neutral/beneficial mutations (left) and the functionally disrupting mutations (right). The blue bars in the plot show the number of mutations from that wildtype amino acid. And the orange bars show the number of mutations to that amino acid. Functionally disrupting mutations that occur a statistical significant number of times (p < 0.01) are show in bold, with an asterisk under the amino acid.