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General selection model



The General Selection Model (GSM) is a model of population genetics that describes how a population's genotype will change when acted upon by natural selection.

Equation

The General Selection Model is encapsulated by the equation:

\Delta q=\frac{pq  \big[q(W_2-W_1) + p(W_1 - W_0)\big ]}{\overline{W}}

where:
p is the frequency of the dominant gene
q is the frequency of the recessive gene
Δq is the rate of evolutionary change of the frequency of the recessive gene
W0,W1,W2 are the relative fitnesses of homozygous dominant, heterozygous, and homozygous recessive genotypes respectively.
\overline{W} is the mean population relative fitness.


In words:

The product of the relative frequencies, pq , is a measure of the genetic variance. The quantity pq is maximized when there is an equal frequency of each gene, when p = q. In the GSM, the rate of change ΔQ is proportional to the genetic variation.

The mean population fitness \overline{W} is a measure of the overall fitness of the population. In the GSM, the rate of change ΔQ is inversely proportional to the mean fitness \overline{W}-- i.e. when the population is maximally fit, no further change can occur.

The remainder of the equation, \big[q(W_2-W_1) + p(W_1 - W_0)\big ] , refers to the mean effect of an allele substitution. In essence, this term quantifies what effect genetic changes will have on fitness.

See also

External links

  • Derivation of the General Selection Model
  • Population Genetics Homework (pdf)
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "General_selection_model". A list of authors is available in Wikipedia.
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