title: Study of double and triple simultaneous substitutions of amino acids in cytochromes C.
abstract: A statistical analysis aimed at obtaining some informations on a possible correlation between simultaneous amino acid substitutions is proposed.  This method is applied to a set of cytochrome C, at the level of tandem and triple substitutions separated along the peptide chain by 1 to 15 peptide bonds.  Monte-Carlo simulations are performed and the results are compared.  We find a significant occurrence of three adjacent amino acid substitutions in which the first replacement requires a two nucleotide substitution. A possible explanation of this fact is proposed on  the basis of covarions.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D003574:Cytochrome c Group / Q000096:biosynthesis*; D005815:Genetic Code; D008954:Models, Biological; D010944:Plants
chemical_list: D003574:Cytochrome c Group