Long-term experimental evolution in Escherichia coli. IX. Characterization of insertion sequence-mediated mutations and rearrangements.
As part of a long-term evolution experiment, two populations of Escherichia coli B adapted to a glucose minimal medium for 10,000 generations. In both populations, multiple IS-associated mutations arose that then went to fixation. We identify the affected genetic loci and characterize the molecular events that produced nine of these mutations. All nine were IS-mediated events, including simple insertions as well as recombination between homologous elements that generated inversions and deletions. Sequencing DNA adjacent to the insertions indicates that the affected genes are involved in central metabolism (knockouts of pykF and nadR), cell wall synthesis (adjacent to the promoter of pbpA-rodA), and ill-defined functions (knockouts of hokB-sokB and yfcU). These genes are candidates for manipulation and competition experiments to determine whether the mutations were beneficial or merely hitchhiked to fixation.
Schneider
D
D
Laboratoire Plasticité et Expression des Génomes Microbiens, Université Joseph Fourier, 38041 Grenoble Cedex 9, France. dominique.schneider@ujf-grenoble.fr
Duperchy
E
E
Coursange
E
E
Lenski
R E
RE
Blot
M
M
D005075:Biological Evolution; D004251:DNA Transposable Elements; D015252:Deoxyribonucleases, Type II Site-Specific; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D017353:Gene Deletion; D015321:Gene Rearrangement; D005798:Genes, Bacterial; D016296:Mutagenesis; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping
D004251:DNA Transposable Elements; D015252:Deoxyribonucleases, Type II Site-Specific; C027440:GATATC-specific type II deoxyribonucleases