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Natural selection and gene substitution*

Published online by Cambridge University Press:  14 April 2009

Motoo Kimura
Affiliation:
National Institute of GeneticsMishima, Japan
James F. Crow
Affiliation:
University of WisconsinMadison, Wisconsin, U.S.A.
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Using models which describe the change, by natural selection, of the actual numbers of genes rather than their relative frequencies, it is demonstrated that the equation familiar to geneticists, i.e. dp/dt = sp(1 − p), is appropriate under a wide range of circumstances. It was pointed out that, for realistic treatment of the evolutionary process through which gene substitutions are repeated, the models must have the property such that the total population number remains constant or nearly constant throughout the process, and is not appreciably influenced by the genes being substituted.

The load or cost for a gene substitution was studied assuming a haploid population and the effects on the load of such factors as epistatic gene interaction in fitness, finite population number and slow change of environment were investigated. The load may become very large under a strong ‘reinforcing’ type epistasis between advantageous genes. In a finite population, the load for one gene substitution may be inflated by about unity if the product of the effective population number (Ne) and the selection coefficient (s) is large but Nesp0 is much smaller than unity, where p0 is the initial gene frequency. On the other hand, slow change of environment may decrease the load somewhat. It was concluded that despite these and other complicating factors, Haldane's original formula, –logep0, for a haploid population (−2 logep0 for the case of a diploid without dominance) is still useful for assessing the approximate amount of selective elimination that accompanies the process of gene substitution in evolution.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1969

References

REFERENCES

Crow, J. F. (1958). Some possibilities for measuring selection intensities in man. Hum. Biol. 30, 113.Google Scholar
Crow, J. F. (1968). The cost of evolution and genetic loads. In Haldane and Modern Biology, pp. 165178. Ed. by Dronamraju, K. R.. Baltimore, Md. U.S.A.: Johns Hopkins Press.Google Scholar
Crow, J. F. & Kimura, M. (1965). The theory of genetic loads. Proc. XI Int. Congr. Genetics 3, 495505.Google Scholar
Darwin, Ch. (1859). The Origin of Species. London: John Murray.Google Scholar
Feller, W. (1966). On the influence of natural selection on population size. Proc. natn. Acad. Sci., U.S.A. 55, 733738.CrossRefGoogle ScholarPubMed
Feller, W. (1967). On fitness and the cost of natural selection. Genet. Res. 9, 115.Google Scholar
Fisher, R. A. (1930). The Genetical Theory of Natural Selection. Oxford: Clarendon Press.CrossRefGoogle Scholar
Haldane, J. B. S. (1924). A mathematical theory of natural and artificial selection. Part I. Trans. Camb. Phil. Soc. 23, 1941.Google Scholar
Haldane, J. B. S. (1957). The cost of natural selection. J. Genet. 55, 511524.CrossRefGoogle Scholar
Haldane, J. B. S. (1960). More precise expressions for the cost of natural selection. J. Genet. 57, 351360.Google Scholar
Kimura, M. (1957). Some problems of stochastic processes in genetics. Ann. Math. Statist. 28, 882901.Google Scholar
Kimura, M. (1965). Attainment of quasi linkage equilibrium when gene frequencies are changing by natural selection. Genetics 52, 875890.Google Scholar
Kimura, M. (1967). On the evolutionary adjustment of spontaneous mutation rates. Genet. Res. 9, 2334.CrossRefGoogle Scholar
Kimura, M. (1968). Evolutionary rate at the molecular level. Nature, Lond. 217, 624626.CrossRefGoogle ScholarPubMed
Kimura, M. & Maruyama, T. (1966). The mutational load with epistatic gene interactions in fitness. Genetics 54, 13371351.Google Scholar
Kimura, M. & Maruyama, T. (1969). The substitutional load in a finite population. Heredity (in the Press).Google Scholar
Van Valen, L. (1965). Selection in natural populations. III. Measurement and estimation. Evolution 19, 514528.Google Scholar
Wright, S. (1931). Evolution in Mendelian populations. Genetics 16, 97159.Google Scholar