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{{short description|Model of population genetics}}
{{more citations needed|date=July 2013}}
The '''general selection model (GSM)''' is a model of [[population genetics]] that describes how a population's [[allele frequencies]] will change when acted upon by [[natural selection]].<ref name="Pierce2006">{{cite book|author=Benjamin A. Pierce|title=Transmission and Population Genetics|url=https://books.google.com/books?id=c6ZHn0IFDWwC|date=9 January 2006|publisher=W. H. Freeman|isbn=978-0-7167-8387-9}}</ref>{{better source|date=June 2019}}

==Equation==
The General Selection Model applied to a single gene with two alleles (let's call them A1 and A2) is encapsulated by the equation:

: <math>\Delta q=\frac{pq \big[q(W_2-W_1) + p(W_1 - W_0)\big ]}{\overline{W}}</math>
:where:

::<math>p</math> is the frequency of allele A1
::<math>q</math> is the frequency of allele A2
::<math>\Delta q</math> is the rate of evolutionary change of the frequency of allele A2
::<math>W_0,W_1, W_2</math> are the [[fitness (biology)|relative fitnesses]] of homozygous A1, heterozygous (A1A2), and homozygous A2 genotypes respectively.
::<math>\overline{W}</math> is the mean population relative fitness.

In words:

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

The mean population fitness <math>\overline{W}</math> is a measure of the overall fitness of the population. In the GSM, the rate of change <math>\Delta Q</math> is inversely proportional to the mean fitness <math>\overline{W}</math>—i.e. when the population is maximally fit, no further change can occur.

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

==See also==
*[[Fitness (biology)|Darwinian fitness]]
*[[Hardy–Weinberg principle]]
*[[Population genetics]]

==References==
{{Reflist}}

[[Category:Population genetics]]

General selection model - Revision history

imported>Maxeto0910: Added short description.