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Evolutionary dynamics of bacteria in a human host environment.

ABSTRACT: Laboratory evolution experiments have led to important findings relating organism adaptation and genomic evolution. However, continuous monitoring of long-term evolution has been lacking for natural systems, limiting our understanding of these processes in situ. Here we characterize the evolutionary dynamics of a lineage of a clinically important opportunistic bacterial pathogen, Pseudomonas aeruginosa, as it adapts to the airways of several individual cystic fibrosis patients over 200,000 bacterial generations, and provide estimates of mutation rates of bacteria in a natural environment. In contrast to predictions based on in vitro evolution experiments, we document limited diversification of the evolving lineage despite a highly structured and complex host environment. Notably, the lineage went through an initial period of rapid adaptation caused by a small number of mutations with pleiotropic effects, followed by a period of genetic drift with limited phenotypic change and a genomic signature of negative selection, suggesting that the evolving lineage has reached a major adaptive peak in the fitness landscape. This contrasts with previous findings of continued positive selection from long-term in vitro evolution experiments. The evolved phenotype of the infecting bacteria further suggests that the opportunistic pathogen has transitioned to become a primary pathogen for cystic fibrosis patients.

SUBMITTER: Yang L

PROVIDER: S-EPMC3088582 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Evolutionary dynamics of bacteria in a human host environment.

Yang Lei L Jelsbak Lars L Marvig Rasmus Lykke RL Damkiær Søren S Workman Christopher T CT Rau Martin Holm MH Hansen Susse Kirkelund SK Folkesson Anders A Johansen Helle Krogh HK Ciofu Oana O Høiby Niels N Sommer Morten O A MO Molin Søren S

Proceedings of the National Academy of Sciences of the United States of America 20110425 18

Laboratory evolution experiments have led to important findings relating organism adaptation and genomic evolution. However, continuous monitoring of long-term evolution has been lacking for natural systems, limiting our understanding of these processes in situ. Here we characterize the evolutionary dynamics of a lineage of a clinically important opportunistic bacterial pathogen, Pseudomonas aeruginosa, as it adapts to the airways of several individual cystic fibrosis patients over 200,000 bacte ...[more]

PMID: 21518885

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Evolutionary dynamics of bacteria in a human host environment.

Publications

Evolutionary dynamics of bacteria in a human host environment.

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