Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Population size and rate of evolution

  • 533 Accesses

  • 106 Citations


It is suggested that in evolution there is much substitution of nearly neutral mutations, for which the selection intensity varies from time to time or from region to region. Since the variance among the selection coefficients of new mutants decreases when the environment becomes uniform, the probability of a mutant being advantageous to the species as a whole increases in more uniform environment (Fig. 1).

Therefore the rate of gene substitution increases in smaller populations, as smaller populations are likely to be distributed over less varied environments.

The adequacy of the model was discussed in relation with the following facts or plausible postulates. 1. A large number of amino acid substitutions during a period corresponding to the formation of new species. 2. Rapid evolution at the phenotypic level of populations having a small size. 3. Many extinctions and expansions of the species in the past.

This is a preview of subscription content, log in to check access.


  1. Crow, J. F.: Proc. 6th Berkeley Symp. Mathematical Statistics and Probability (in press) (1972).

  2. Fisher, R. A.: The genetical theory of natural selection. Oxford: Clarendon Press 1930.

  3. Fitch, W. M., Markowitz, E.: Biochem. Genet.4, 579–593 (1970).

  4. Haldane, J. B. S.: The causes of evolution. New York: Cornell Univ. Press 1932.

  5. Haldane, J. B. S.: J. Genet.55, 511–524 (1957).

  6. Kimura, M.: Ann. Math. Stat.28, 882–901 (1957).

  7. Kimura, M.: Genetics47, 713–719 (1962).

  8. King, J. L., Jukes, T. H.: Science164, 788–798 (1969).

  9. Margoliash, E., Barlow, G. H., Byers, V.: Nature (Lond.)288, 723–726 (1970).

  10. Mayr, E.: Animal species and evolution. Cambridge: The Belknap Press of Harvard Univ. Press 1963.

  11. Ohno, S.: Evolution by gene duplication. Berlin-Heidelberg-New York: Springer 1970.

  12. Ohta, T.: Genet. Res.19, 33–38 (1972a).

  13. Ohta, T.: J. molec. Evolution1, 150–157 (1972b).

  14. Ohta, T., Kimura, M.: Nature (Lond.)233, 118–119 (1971).

  15. Simpson, G. G.: Tempo and mode in evolution. New York: Columbia Univ. Press 1944.

  16. Uzzell, T., Corbin, K. W.: Science172, 1089–1096 (1971).

  17. Wright, S.: Anat. Rec.44, 287 (1929).

  18. Wright, S.: Genetics16, 97–159 (1931).

  19. Wright, S.: J. Genet.30, 257–266 (1935).

  20. Wright, S.: Amer. Naturalist74, 232–248 (1940).

  21. Wright, S.: Genetics28, 114–138 (1943).

  22. Wright, S.: Evolution2, 279–294 (1948).

  23. Wright, S.: Amer. Naturalist90, 5–24 (1956).

Download references

Author information

Additional information

Contribution No. 871 from the National Institute of Genetics, Mishima, Shizuokaken 411 Japan.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ohta, T. Population size and rate of evolution. J Mol Evol 1, 305–314 (1972). https://doi.org/10.1007/BF01653959

Download citation

Key words

  • Evolutionary Rate
  • Environmental Diversity
  • Nearly Neutral Mutations
  • Population Size