Hernandez-Lopez A., Chabrol O., Royer-Carenzi M., Merhej V., Pontarotti P., Raoult Didier. (2013). To tree or not to tree ? Genome-wide quantification of recombination and reticulate evolution during the diversification of strict intracellular bacteria. Genome Biology and Evolution, 5 (12), p. 2305-2317. ISSN 1759-6653.
Titre du document
To tree or not to tree ? Genome-wide quantification of recombination and reticulate evolution during the diversification of strict intracellular bacteria
Année de publication
2013
Auteurs
Hernandez-Lopez A., Chabrol O., Royer-Carenzi M., Merhej V., Pontarotti P., Raoult Didier
Source
Genome Biology and Evolution, 2013,
5 (12), p. 2305-2317 ISSN 1759-6653
It is well known that horizontal gene transfer (HGT) is a major force in the evolution of prokaryotes. During the adaptation of a bacterial population to a new ecological niche, and particularly for intracellular bacteria, selective pressures are shifted and ecological niches reduced, resulting in a lower rate of genetic connectivity. HGT and positive selection are therefore two important evolutionary forces in microbial pathogens that drive adaptation to new hosts. In this study, we use genomic distance analyses, phylogenomic networks, tree topology comparisons, and Bayesian inference methods to investigate to what extent HGT has occurred during the evolution of the genus Rickettsia, the effect of the use of different genomic regions in estimating reticulate evolution and HGT events, and the link of these to host range. We show that ecological specialization restricts recombination occurrence in Rickettsia, but other evolutionary processes and genome architecture are also important for the occurrence of HGT. We found that recombination, genomic rearrangements, and genome conservation all show evidence of network-like evolution at whole-genome scale. We show that reticulation occurred mainly, but not only, during the early Rickettsia radiation, and that core proteome genes of every major functional category have experienced reticulated evolution and possibly HGT. Overall, the evolution of Rickettsia bacteria has been tree-like, with evidence of HGT and reticulated evolution for around 10-25% of the core Rickettsia genome. We present evidence of extensive recombination/incomplete lineage sorting (ILS) during the radiation of the genus, probably linked with the emergence of intracellularity in a wide range of hosts.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Entomologie médicale / Parasitologie / Virologie [052]
Identifiant IRD
PAR00011279
