Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 1980 Dec;16(2):111-20.
doi: 10.1007/BF01731581.

A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences

M Kimura
Comparative Study

A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences

M Kimura. J Mol Evol. 1980 Dec.

Abstract

Some simple formulae were obtained which enable us to estimate evolutionary distances in terms of the number of nucleotide substitutions (and, also, the evolutionary rates when the divergence times are known). In comparing a pair of nucleotide sequences, we distinguish two types of differences; if homologous sites are occupied by different nucleotide bases but both are purines or both pyrimidines, the difference is called type I (or "transition" type), while, if one of the two is a purine and the other is a pyrimidine, the difference is called type II (or "transversion" type). Letting P and Q be respectively the fractions of nucleotide sites showing type I and type II differences between two sequences compared, then the evolutionary distance per site is K = -(1/2) ln [(1-2P-Q) square root of 1-2Q]. The evolutionary rate per year is then given by k = K/(2T), where T is the time since the divergence of the two sequences. If only the third codon positions are compared, the synonymous component of the evolutionary base substitutions per site is estimated by K'S = -(1/2) ln (1-2P-Q). Also, formulae for standard errors were obtained. Some examples were worked out using reported globin sequences to show that synonymous substitutions occur at much higher rates than amino acid-altering substitutions in evolution.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Proc Natl Acad Sci U S A. 1974 Jul;71(7):2848-52 - PubMed
    1. Cell. 1978 Dec;15(4):1125-32 - PubMed
    1. J Biol Chem. 1977 Jul 25;252(14):5040-53 - PubMed
    1. J Mol Evol. 1979 Mar 15;12(3):219-36 - PubMed
    1. Cell. 1977 Apr;10(4):571-85 - PubMed

Publication types

LinkOut - more resources