Genome characterisation of the genus Francisella reveals insight into similar evolutionary paths in pathogens of mammals and fish

BMC Genomics

Research Article

Anders Johansson¹  Kerstin Svensson²  Petter Lindgren²  Jon Ahlinder²  Andreas Sjödin²  Mats Forsman²  Pär Larsson²  Caroline Öhrman²  Samuel Duodu³  Duncan J Colquhoun³ 

[1] Department of Clinical Microbiology, Umeå University, SE-901 85, Umeå, Sweden;Division of CBRN Security and Defence, FOI - Swedish Defence Research Agency, Umeå, Sweden;Section for Bacteriology, Norwegian Veterinary Institute, Postbox 750 sentrum, 0106, Oslo, Norway;

关键词: Francisella;    Next-generation sequencing;    Recombination;    Fish;    Genetics;    Evolution;   

DOI  :  10.1186/1471-2164-13-268

 received in 2012-01-03, accepted in 2012-06-07,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundPrior to this study, relatively few strains of Francisella had been genome-sequenced. Previously published Francisella genome sequences were largely restricted to the zoonotic agent F. tularensis. Only limited data were available for other members of the Francisella genus, including F. philomiragia, an opportunistic pathogen of humans, F. noatunensis, a serious pathogen of farmed fish, and other less well described endosymbiotic species.ResultsWe determined the phylogenetic relationships of all known Francisella species, including some for which the phylogenetic positions were previously uncertain. The genus Francisella could be divided into two main genetic clades: one included F. tularensis, F. novicida, F. hispaniensis and Wolbachia persica, and another included F. philomiragia and F. noatunensis.Some Francisella species were found to have significant recombination frequencies. However, the fish pathogen F. noatunensis subsp. noatunensis was an exception due to it exhibiting a highly clonal population structure similar to the human pathogen F. tularensis.ConclusionsThe genus Francisella can be divided into two main genetic clades occupying both terrestrial and marine habitats. However, our analyses suggest that the ancestral Francisella species originated in a marine habitat. The observed genome to genome variation in gene content and IS elements of different species supports the view that similar evolutionary paths of host adaptation developed independently in F. tularensis (infecting mammals) and F. noatunensis subsp. noatunensis (infecting fish).

【 授权许可】

CC BY   
© Sjödin et al.; 2012