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Titolo:
Experimental analysis of molecular events during mutational periodic selections in bacterial evolution
Autore:
Notley-McRobb, L; Ferenci, T;
Indirizzi:
Univ Sydney, Dept Microbiol, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 robiol, Sydney, NSW 2006, Australia
Titolo Testata:
GENETICS
fascicolo: 4, volume: 156, anno: 2000,
pagine: 1493 - 1501
SICI:
0016-6731(200012)156:4<1493:EAOMED>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
HORIZONTAL GENE-TRANSFER; ESCHERICHIA-COLI; EXPERIMENTAL POPULATIONS; GLUCOSE; ENVIRONMENT; ADAPTATION; PATHWAYS; MUTATORS; GENOMES; FITNESS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Ferenci, T Univ Sydney, Dept Microbiol, G08, Sydney, NSW 2006, Australia Univ Sydney G08 Sydney NSW Australia 2006 , NSW 2006, Australia
Citazione:
L. Notley-McRobb e T. Ferenci, "Experimental analysis of molecular events during mutational periodic selections in bacterial evolution", GENETICS, 156(4), 2000, pp. 1493-1501

Abstract

A fundamental feature of bacterial evolution is a succession of adaptive mutational sweeps when fitter mutants: lake over a population. To understandthe processes involved in mutational successions, Escherichia coli continuous cultures were analyzed for changes at two loci where mutations provide strong transport advantages to fitness under steady-state glucose limitation. Three separate sweeps, observed as classic periodic selection events causing a change in the frequency of neutral mutations (in fhuA causing phage T5 resistance), were identified with changes at particular loci. Two of thesweeps were associated with a reduction in the frequency of neutral mutations and the concurrent appearance of at least 13 alleles at the mgl or mlc loci, respectively. These mgl and mlc polymorphisms were of many mutationaltypes, so were not the result of a mutator or directed mutation event. Thethird sweep observed was altogether distinct and involved hitchhiking between T5 resistance and advantageous mgl mutations. Moreover, the hitchhikingevent coincided with an increase in mutation rates, due to the transient appearance of a strong mutator in the population. The spectrum of mgl mutations among mutator isolates was distinct and due to mutS. The mutator-associated periodic selection also resulted in mgl and fhuA polymorphism in the sweeping population. These examples of periodic selections maintained significant genotypic diversity even in a rapidly evolving culture, with no individual "winner clone" or genotype purging the population.

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Documento generato il 02/04/20 alle ore 13:05:38