The evolution of genetic canalization under fluctuating selection.

Détails

ID Serval
serval:BIB_74F5E926B5C3
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
The evolution of genetic canalization under fluctuating selection.
Périodique
Evolution
Auteur(s)
Kawecki T.J.
ISSN
0014-3820[print], 0014-3820[linking]
Statut éditorial
Publié
Date de publication
2000
Peer-reviewed
Oui
Volume
54
Numéro
1
Pages
1-12
Langue
anglais
Résumé
If the direction of selection changes from generation to generation, the ability to respond to selection is maladaptive: the response to selection in one generation leads to reduced fitness in the next. Because the response is determined by the amount of genetic variance expressed at the phenotypic level, rapidly fluctuating selection should favor modifier genes that reduce the phenotypic effect of alleles segregating at structural loci underlying the trait. Such reduction in phenotypic expression of genetic variation has been named "genetic canalization." I support this argument with a series of two- and multilocus models with alternating linear selection and Gaussian selection with fluctuating optimum. A canalizing modifier gene affects the fitness of its carriers in three ways: (1) it reduces the phenotypic consequences of genetic response to previous selection; (2) it reduces the genetic response to selection, which is manifested as linkage disequilibrium between the modifier and structural loci; and (3) it reduces the phenotypic variance. The first two effects reduce fitness under directional selection sustained for several generations, but improve fitness when the direction of selection has just been reversed. The net effect tends to favor a canalizing modifier under rapidly fluctuating selection regimes (period of eight generations or less). The third effect improves fitness of the modifier allele if the fitness function is convex and reduces it if the function is concave. Under fluctuating Gaussian selection, the population is more likely to experience the concave portion of the fitness function when selection is stronger. Therefore, only weak to moderately strong fluctuating Gaussian selection favors genetic canalization. This paper considerably broadens the conditions that favor genetic canalization, which so far has only been postulated to evolve under long-term stabilizing selection.
Mots-clé
Alleles, Epistasis, Genetic, Evolution, Genetic Variation, Linear Models, Models, Genetic, Phenotype, Selection, Genetic
Pubmed
Web of science
Création de la notice
19/11/2007 11:33
Dernière modification de la notice
03/03/2018 18:22
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