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| | Greetings! I am Myrtle Shroyer. My family life in Minnesota and my family members loves it. My working day job is a librarian. To do aerobics is a factor that I'm totally addicted to.<br><br>Feel free to visit my webpage: [http://internetmarketingarcade.com/groups/valuable-guidance-for-successfully-treating-yeast-infections/ http://internetmarketingarcade.com] |
| The '''mutation–selection balance''' is a classic result in [[population genetics]]
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| first derived in the 1920s by [[John Burdon Sanderson Haldane]] and [[Ronald Fisher|R.A. Fisher]].
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| A genetic variant that is deleterious will not necessarily disappear immediately from a
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| population. Its frequency, when it first appears in a population of N individuals, will
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| be 1/N (or 1/2N in a [[diploid]] population), and this frequency might drift up and down a
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| bit before returning to zero. If the population is large enough, or if the [[mutation]]
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| rate <math>\mu</math> is high enough, i.e., if <math>\mu*N</math> is high enough, then one has to consider additional
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| mutations. In a hypothetical infinite population, the frequency will never return to
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| zero. Instead, it will reach an equilibrium value that reflects the balance between
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| mutation (pushing the frequency upward) and [[selection]] (pushing it downward), thus
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| the name ''mutation–selection balance''.
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| If 's' is the deleterious selection coefficient (the decrease in relative fitness), then the equilibrium frequency 'f' of an [[allele]] in mutation–selection balance is approximately <math>f = \mu/s</math> in [[haploid]]s, or for the case of a dominant allele in diploids. For a recessive allele in
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| a diploid population, <math>f = \sqrt{\mu \over{s}}</math>. A useful approximation for
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| alleles of intermediate dominance is that f ~ <math>\mu/(sh)</math>, where h is the coefficient of
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| dominance. These formulae are all approximate because
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| they ignore back-mutation, typically a trivial effect.
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| The mutation–selection balance has the practical use of allowing estimates of
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| mutation rates from data on deleterious alleles (see examples on pp. 85–89 of Crow, 1986).
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| For population geneticists, it provides a simple model for thinking about how
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| variation persists in natural populations.
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| == External links ==
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| * http://www.blackwellpublishing.com/ridley/a-z/Mutation-selection_balance.asp
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| * J. F. Crow (1986). ''Basic concepts in population, quantitative, and evolutionary genetics''. New York: W.H. Freeman. p. 273.
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| {{DEFAULTSORT:Mutation-selection balance}}
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| [[Category:Mutation]]
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| [[Category:Selection]]
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Greetings! I am Myrtle Shroyer. My family life in Minnesota and my family members loves it. My working day job is a librarian. To do aerobics is a factor that I'm totally addicted to.
Feel free to visit my webpage: http://internetmarketingarcade.com