title: Molecular handles on adaptive mutation.
abstract: In one experimental system, several handles on the molecular mechanism of apparent adaptive mutation have emerged. The system is reversion of a lac frameshift mutation in Escherichia coli. The molecular handles include a requirement for homologous recombination; the implication of DNA double-strand breaks as a molecular intermediate; a unique sequence spectrum of -1 deletions in mononucleotide repeats which implies polymerase errors, and also implies a failure of postsynthesis mismatch repair on those errors; and the involvement of sexual functions at some stage of the process. These molecular handles are revealing an unexpected new mechanism of mutagenesis.
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: S M
authors.initials: SM
authors.lastname: Rosenberg
authors.forename: R S
authors.initials: RS
authors.lastname: Harris
authors.forename: J
authors.initials: J
authors.lastname: Torkelson
mesh_terms: D003227:Conjugation, Genetic; D004249:DNA Damage; D004260:DNA Repair; D004926:Escherichia coli / Q000235:genetics*; D016368:Frameshift Mutation; D007763:Lac Operon / Q000235:genetics; D010957:Plasmids; D011995:Recombination, Genetic; D013489:Suppression, Genetic