ON THE PROBABILITY OF CODON-CODON MUTATIONAL REPLACEMENTS

The content of the data base of blocks of protein sequences (Henikoff, S.; Henikoff, J. G. Genomics 1994, 19, 97-107) were used in order to locate the homologous gene sequences. Aligning these sequences the 64 x 64 matrix of codon-codon interchanges was constructed. Matrices were generated for various phylogenetical groups of organisms and for vari ous degrees of relatedness of source sequences. The resulting matrices provide the information about the codon usage: the frequency of silen t and the frequency of recognizable mutations. An attempt was made to interpret the codon-codon interchange frequencies in the spirit of the supposition that the evolutionary events are of predominantly stochas tic character.