title: Competition between transposable elements and mutator genes in bacteria.
abstract: Although both genotypes with elevated mutation rate (mutators) and mobilization of insertion sequence (IS) elements have substantial impact on genome diversification, their potential interactions are unknown. Moreover, the evolutionary forces driving gradual accumulation of these elements are unclear: Do these elements spread in an initially transposon-free bacterial genome as they enable rapid adaptive evolution? To address these issues, we inserted an active IS1 element into a reduced Escherichia coli genome devoid of all other mobile DNA. Evolutionary laboratory experiments revealed that IS elements increase mutational supply and occasionally generate variants with especially large phenotypic effects. However, their impact on adaptive evolution is small compared with mismatch repair mutator alleles, and hence, the latter impede the spread of IS-carrying strains. Given their ubiquity in natural populations, such mutator alleles could limit early phase of IS element evolution in a new bacterial host. More generally, our work demonstrates the existence of an evolutionary conflict between mutation-promoting mechanisms.
authors.affiliation: Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Center, Szeged, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Fehér
authors.forename: Balázs
authors.initials: B
authors.lastname: Bogos
authors.forename: Orsolya
authors.initials: O
authors.lastname: Méhi
authors.forename: Gergely
authors.initials: G
authors.lastname: Fekete
authors.forename: Bálint
authors.initials: B
authors.lastname: Csörgo
authors.forename: Károly
authors.initials: K
authors.lastname: Kovács
authors.forename: György
authors.initials: G
authors.lastname: Pósfai
authors.forename: Balázs
authors.initials: B
authors.lastname: Papp
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Hurst
authors.forename: Csaba
authors.initials: C
authors.lastname: Pál
mesh_terms: D053843:DNA Mismatch Repair / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D019143:Evolution, Molecular; D005798:Genes, Bacterial / Q000235:genetics*; D056084:Genetic Fitness; D005838:Genotype; D054884:Host-Pathogen Interactions / Q000235:genetics; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D059645:Mutation Rate; D009876:Operon / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements