Mutation–Selection Balance

Hamish G Spencer, University of Otago, Dunedin, New Zealand

Published online: April 2001

DOI: 10.1038/npg.els.0001768

An organism's genome is continually being altered by mutations, the vast majority of which are harmful to the organism or its descendants, because they reduce the bearer's viability or fertility. Consequently, every generation, natural selection acts to weed out these deleterious mutations. The opposing processes of mutation and selection balance each other so that the frequency in a population of a deleterious mutation remains at an equilibrium value determined by the strength of selection and the frequency of mutation.

Keywords: natural selection; mutation; genetic load; population genetics

Figure 1. Equilibrium allele frequency, , as a function of the level of dominance, h, in the standard model of mutation–selection balance. When h = 0, the allele is fully recessive; when h = 1 it is completely dominant. The other parameter values are s = 0.5 and = 5 × 10–7. Note the log scale of the y-axis, which de-emphasizes the sharp drop in as h increases from zero.
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Related Sub-Topics:

Molecular Evolution | Selection and Variation | Population Structure and Genetics | Variation by Mutation and Recombination
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Article Title: Mutation–Selection Balance
 
How to Cite close
Spencer, Hamish G(Apr 2001) Mutation–Selection Balance. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001768]