Dynamics and impact of homologous recombination on the evolution of Legionella pneumophila

• DOI: 10.1371/journal.pgen.1006855
• Publication Date: 2017-06-26T17:36:49Z
• Authors: Sophia David; Leonor Sánchez-Busó; Simon R. Harris; Pekka Marttinen; Christophe Rusniok; Carmen Buchrieser; Timothy G. Harrison; Julian Parkhill
• Keywords: Legionella

Legionella pneumophila is an environmental bacterium and the causative agent of Legionnaires' disease. Previous genomic studies have shown that recombination accounts for a high proportion (>96%) diversity within several major disease-associated sequence types (STs) L. pneumophila. This suggests represents potentially important force shaping adaptation virulence. Despite this, little known about biological effects in pneumophila, particularly with regards to homologous (whereby genes are replaced alternative allelic variants). Using newly available population data, we disentangled events arising from non-homologous six STs (subsp. pneumophila), subsequently performed detailed characterisation dynamics impact recombination. We identified "hotspots" include regions containing outer membrane proteins, lipopolysaccharide (LPS) region Dot/Icm effectors, which provide interesting clues selection pressures faced by Inference origin recombined showed isolates most frequently imported DNA belonging their own clade, but also occasionally other clades same subspecies. supports hypothesis possibility horizontal exchange new adaptations between subspecies may been critical factor recent emergence clinically diverse backgrounds. However, acquisition another subspecies, subsp. fraseri, was rarely observed, suggesting existence barrier and/or ongoing speciation two Finally, suggest multi-fragment occur whereby multiple non-contiguous segments originate molecule donor into recipient genome during single episode