An estimation of the number of invariable sites is necessary for the accurate estimation of the number of nucleotide substitutions since a common ancestor.
D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D005075:Biological Evolution; D004247:DNA / Q000235:genetics*; D005796:Genes; D008433:Mathematics; D008957:Models, Genetic; D009154:Mutation
D004247:DNA