Hostname: page-component-77c89778f8-5wvtr Total loading time: 0 Render date: 2024-07-23T04:44:06.072Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of dominance and size of population on response to mass selection*

Published online by Cambridge University Press:  14 April 2009

Ken-Ichi Kojima
Ken-Ichi Kojima
Affiliation:
Department of Genetics, North Carolina State College, U.S.A.

Extract

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.

A theory of mass selection in a small population was developed, and the mean change in gene frequencies, the variance of gene frequency changes and the expected gain in the mean phenotypic value of an offspring population were formulated in terms of a generalized selection differential and the additive and dominance effects of genes.

The magnitude of the variance of changes in gene frequency was compared with the magnitude of the variance expected from the genetic random drift in a population with the same gene frequency and of the same size in absence of selection. The former was found to be usually smaller than the latter when the gene frequency ranged from intermediate to high and when selection was directed for a high performance.

The usual prediction equation for gain from selection in an infinite population was compared with the expected gain formula derived for a small population. The size of the population did not cause a serious difference between the two expected gains when there was no dominance effect of genes. Dominance alone could cause the usual prediction to be slightly more biased. The joint effects of the finite size of population and dominance gene action could amount to a considerable bias in the usual prediction equation. Such a bias can be, in the main, accounted for by the inbreeding depression.

Type
Research Article
Information
Genetics Research , Volume 2 , Issue 2 , July 1961 , pp. 177 - 188
Copyright
Copyright © Cambridge University Press 1961

References

REFERENCES

Clayton, G. A., Morris, J. A. & Robertson, A. (1957). An experimental check on quantitative genetical theory. I: Short-term responses to selection. J. Genet. 55, 131–151.CrossRefGoogle Scholar
Fisher, R. A. & Yates, F. (1953). Statistical Tables for Biological, Agricultural and Medical Research. Oliver and Boyd, London.Google Scholar
Fraser, A. S. (1957). Simulation of genetic systems by automatic digital computers. II: Effects of linkage on rates of advance under selection. Aust. J. biol. Sci. 10, 492–499.CrossRefGoogle Scholar
Fraser, A. S. (1960). Simulation of genetic systems by automatic digital computers. V: Linkage, dominance and epistasis. Biometrical Genetics, 70–83. Pergamon Press, New York.Google Scholar
Kojima, K. (1959). Role of epistasis and overdominance in stability of equilibrium with selection. Proc. nat. Acad. Sci., Wash., 45, 984–989.Google Scholar
Martin, F. G. & Cockerham, C. C. (1960). High speed selection studies. Biometrical Genetics, 37–45. Pergamon Press, New York.Google Scholar
Ruben, H. (1954). On the moments of order statistics in samples from normal populations. Biometrika, 41, 200–226.Google Scholar