title: Convergence of Campylobacter species: implications for bacterial evolution.
abstract: The nature of species boundaries in bacteria remains controversial. In particular, the mechanisms of bacterial speciation and maintenance in the face of frequent genetic exchange are poorly understood. Here, we report patterns of genetic exchange that show two closely related zoonotic pathogenic species, Campylobacter jejuni and Campylobacter coli, are converging as a consequence of recent changes in gene flow. Population expansion into a novel ecological niche generated by human activity is the most probable explanation for the increase in genetic exchange between these species. Bacterial speciation can therefore occur by mechanisms analogous to those seen in metazoans, where genetic diversification and incipient speciation caused by ecological factors have been reported in several genera.
authors.affiliation: Departments of Zoology and Statistics, University of Oxford, Peter Medawar Building, South Parks Road, Oxford OX1 3SY, UK.
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Sheppard
authors.forename: Noel D
authors.initials: ND
authors.lastname: McCarthy
authors.forename: Daniel
authors.initials: D
authors.lastname: Falush
authors.forename: Martin C J
authors.initials: MC
authors.lastname: Maiden
mesh_terms: D000383:Agriculture; D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D017000:Campylobacter coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016123:Campylobacter jejuni / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016000:Cluster Analysis; D051456:Gene Flow; D005798:Genes, Bacterial; D049810:Genetic Speciation; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D006824:Hybridization, Genetic; D007422:Intestines / Q000382:microbiology; D011995:Recombination, Genetic