Fisher's fundamental theorem of natural selection
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In population genetics, Ronald Fisher's fundamental theorem of natural selection was originally stated as:
- "The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time."
Or, in more modern terminology:
- "The rate of increase in the mean fitness of any organism at any time ascribable to natural selection acting through changes in gene frequencies is exactly equal to its genic variance in fitness at that time". (A.W.F. Edwards 1994)
History
The theorem was first formulated by Ronald Fisher in his 1930 book The Genetical Theory of Natural Selection. Fisher held that "It is not a little instructive that so similar a law should hold the supreme position among the biological sciences". However, for forty years it was misunderstood, it being read as saying that the average fitness of a population would always increase, and models showed this not to be the case. The misunderstanding can be seen largely as a result of Fisher's feud with the American geneticist Sewall Wright primarily about adaptive landscapes.
The American George R. Price reformulated the fundamental theorem using the Price equation in 1972, it was found not to be a strict theorem, as it is an oversimplification, but nevertheless has merit.
References
- Edwards, A.W.F. (1994) The fundamental theorem of natural selection. Biological Reviews 69:443–474.
- Fisher, R.A. (1930). The Genetical Theory of Natural Selection. Clarendon Press, Oxford.
- Frank, S.A. (1997) The Price Equation, Fisher's fundamental theorem, kin selection, and causal analysis. Evolution 51:1712-1729. Abstract (http://stevefrank.org/abstracts/97Evol-Causal.html) - page for pdfs (http://stevefrank.org/reprints-choice/97Evol-Causal-R.html)
- Frank, S.A. (1998) Foundation of Social Evolution. Princeton: Princeton University Press. Book's website (http://stevefrank.org/foundations/foundations.html) ISBN 0691059349
- Frank, S.A. and Slatkin, M. (1992) Fisher's fundamental theorem of natural selection. Trends in Ecology and Evolution 7:92-95. abstract (http://stevefrank.org/abstracts/92TREE.html) - pdfs (http://stevefrank.org/reprints-choice/92TREE-R.html)
- Grafen, A. (2000) Developments of the Price equation and natural selection under uncertainty. Proceedings of the Royal Society of London B, 267:1223–1227.
- Grafen, A. (2002) A first formal link between the Price equation and an optimisation program. Journal of Theoretical Biology 217:75–91.
- Price, G.R. (1972). Fisher's "fundamental theorem" made clear. Annals of Human Genetics 36:129-140
External links
- Grafen Fisher the evolutionary biologist http://users.ox.ac.uk/~grafen/cv/fisher.pdf
- http://www.peregrine.dk/subjects/FISH.HTM
| Topics in population genetics |
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| Key concepts: Hardy-Weinberg law | Fisher's fundamental theorem | neutral theory |
| Selection: natural | sexual | artificial | ecological |
| Genetic drift: small population size | population bottleneck | founder effect |
| Founders: Ronald Fisher | J.B.S. Haldane | Sewall Wright |
| Related topics: evolution | microevolution | evolutionary game theory | fitness landscape |
| List of evolutionary biology topics |