The evolution of bacterial viruses: Phage life history evolution and the lysogenic conversion of Vibrio cholerae

Bacteriophage infection can convert non-toxigenic bacteria into strains with disease-causing potential if transferred genes bestow pathogenicity onto their bacterial host. Here, the horizontal transfer of genes between distantly related species allows substantial amounts of DNA to be both introduced into and deleted from the bacterial chromosomes, allowing for rapid adaptation and generating the largely mosaic genomes observed today. Recently, the implications this has for the evolution of bacterial diversity has generated much interest in the evolution of such phages; however few theoretical studies have explored this process in much detail. Previous theory typically assumes phage infection is detrimental to its host and transferred genes must confer some benefit to avoid elimination, but not all phage replication modes validate this assumption. For example, chronic phages exploit their hosts' secretion systems to excrete infectious particles from living hosts, and it is unclear how selection acts on this phage trait. (Abstract shortened by UMI.)...