The nonidentity of invariable positions in the cytochromes c of different species.
D005075:Biological Evolution; D003580:Cytochromes / Q000032:analysis / Q000145:classification*; D005658:Fungi; D005796:Genes; D005815:Genetic Code; D014644:Genetic Variation; D007448:Invertebrates; D008433:Mathematics; D008967:Molecular Biology; D009154:Mutation; D011110:Polymorphism, Genetic; D011336:Probability; D013045:Species Specificity
D003580:Cytochromes