Each protein has its own rate, and that rate is constant across phylogenies (i.e., hemoglobin does not evolve at the same rate as cytochrome c, but hemoglobins from humans, mice, etc. do have comparable rates of evolution.).
Cada proteína ten a súa propia taxa, e a taxa é constante a través das distintas filoxenias (é dicir, a hemoglobina non evoluciona coa mesma taxa que o citocromo c, pero a hemoglobina de humanos, ratos etc. si ten taxas comparables de evolución).