Evolutionary dynamics of bacteria in a human host environment

• DOI: 10.1073/pnas.1018249108
• Publication Date: 2011-04-26T03:05:55Z
• Authors: Lei Yang; Lars Jelsbak; Rasmus Lykke Marvig; Søren Damkiær; Christopher T. Wo...; Martin Holm Rau; Susse Kirkelund H...; Anders Folkesson; Helle Krogh Johansen; Oana Ciofu; Niels Høiby; Morten O. A. Sommer; Søren Molin
• Keywords: Lineage (genetic); Experimental Evolution; Evolutionary Dynamics; Host adaptation

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