Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-25T18:20:47.779Z Has data issue: false hasContentIssue false
  • English
  • Français

The effects of normalizing and disruptive selection on genes for recombination

Published online by Cambridge University Press:  14 April 2009

J. Maynard Smith
J. Maynard Smith
Affiliation:
School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, U.K.
Rights & Permissions [Opens in a new window]

Summary

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Deterministic simulations have been carried out of populations under normalizing and disruptive selection for a trait determined by genes with additive effects at six loci. In some simulations a pair of alleles at a seventh locus determined the rate of recombination between the seven loci. Normalizing selection with a single optimum, fixed or fluctuating, invariably led to genetic homozygosity. If the optimum fluctuates widely, the approach to homozygosity may be accompanied by a large decline in the mean fitness of the population. Disruptive selection was simulated by having two ‘niches’ with separate optima and separate density-dependent regulation, but with the adult population mating randomly. If the optima are widely separated, this leads to stable polymorphism. Selection produced linkage disequilibrium, normalizing selection causing repulsion and disruptive selection coupling between + and − alleles. This linkage disequilibrium accelerates the phenotypic response to selection, but delays changes in gene frequency. Selection always favoured alleles for low recombination at the expense of alleles for high recombination.

Type
Research Article
Information
Genetics Research , Volume 33 , Issue 2 , April 1979 , pp. 121 - 128
Copyright
Copyright © Cambridge University Press 1979

References

REFERENCES

Bulmer, M. G. (1971 a). Stable equilibria under the two-island model. Heredity 27, 321–330.CrossRefGoogle ScholarPubMed
Bulmer, M. G. (1971 b). The effect of selection on genetic variability. American Naturalist 105, 201–211.CrossRefGoogle Scholar
Bulmer, M. G. (1974). Linkage disequilibrium and genetic variability. Genetical Research, Cambridge 23, 281–289.CrossRefGoogle ScholarPubMed
Bulmer, M. G. (1976). The effect of selection on genetic variability: a simulation study. Genetical Research, Cambridge 28, 101–117.CrossRefGoogle ScholarPubMed
Charlesworth, B. (1976). Recombination modification in a fluctuating environment. Genetics 83, 181–195.CrossRefGoogle Scholar
Dempster, E. R. (1955). Maintenance of genetic heterogeneity. Cold Spring Harbour Symposium on Quantitative Biology 20, 25–32.CrossRefGoogle ScholarPubMed
Franklin, I. & Lewontin, R. C. (1970). Is the gene the unit of selection? Genetics 65, 707–734.CrossRefGoogle ScholarPubMed
Lande, R. (1975). The maintenance of genetic variability by mutation in a polygenic character with linked loci. Genetical Research, Cambridge 26, 221–235.CrossRefGoogle Scholar
Lande, R. (1977). The influence of the mating system on the maintenance of genetic variability in polygenic characters. Genetics 86, 485–498.CrossRefGoogle ScholarPubMed
Levene, H. (1953). Genetic equilibrium when more than one ecological niche is available. American Naturalist 87, 131–133.CrossRefGoogle Scholar
Robertson, A. (1956). The effect of selection against extreme deviants based on deviation or on homozygosis. Journal of Genetics 54, 236–248.CrossRefGoogle Scholar
Schaap, T. (1979). Why should the genome congeal? Nature (in the Press).CrossRefGoogle Scholar
Treisman, M. (1976). The evolution of sexual reproduction: a model which assumes individual selection. Journal of Theoretical Biology 60, 421–431.CrossRefGoogle Scholar