Figure 2.

The expected frequencies of amino-acid to amino-acid mutations versus observed frequencies of the genetic disease mutations, nonsynonymous benign SNPs, and interspecies mutations. Comparison with (a) genetic disease mutations from the Mendelian Inheritance in Man (MIM) database [7], (b) nonsynonymous benign SNPs, based on the study by Stephens et al. [9], and (c) interspecies mutations based on the PAM1 matrix [10]. Each point in the figure represents a certain type of amino-acid to amino-acid mutation. Only amino-acid transitions resulting from single-nucleotide mutations in amino-acid codons were considered. The mutation frequencies in each class (benign, disease and interspecies) were normalized to 100.