Contrasting dynamics of a mutator allele in asexual populations of differing size.
Evolution
; 66(7): 2329-34, 2012 Jul.
Article
em En
| MEDLINE
| ID: mdl-22759305
ABSTRACT
Mutators have been shown to hitchhike in asexual populations when the anticipated beneficial mutation supply rate of the mutator subpopulation, NU(b) (for subpopulation of size N and beneficial mutation rate U(b)) exceeds that of the wild-type subpopulation. Here, we examine the effect of total population size on mutator dynamics in asexual experimental populations of Saccharomyces cerevisiae. Although mutators quickly hitchhike to fixation in smaller populations, mutator fixation requires more and more time as population size increases; this observed delay in mutator hitchhiking is consistent with the expected effect of clonal interference. Interestingly, despite their higher beneficial mutation supply rate, mutators are supplanted by the wild type in very large populations. We postulate that this striking reversal in mutator dynamics is caused by an interaction between clonal interference, the fitness cost of the mutator allele, and infrequent large-effect beneficial mutations in our experimental populations. Our work thus identifies a potential set of circumstances under which mutator hitchhiking can be inhibited in natural asexual populations, despite recent theoretical predictions that such populations should have a net tendency to evolve ever-higher genomic mutation rates.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Reprodução Assexuada
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Saccharomyces cerevisiae
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Proteínas de Saccharomyces cerevisiae
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Proteína 2 Homóloga a MutS
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Taxa de Mutação
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Evolution
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos