DNA breakage surprisingly rare

DNA breakage during replication in Escherichia coli occurs at a frequency 20-100 times lower than previously thought, according to a report published this week in Nature Genetics, which describes a new technique to visualize strand breaks in vivo."We can be pretty confident...the researchers are as close as you can get [to the real number of breaks]," Aidan Doherty, at the University of Sussex Center for Genome Damage and Stability, who was not involved in the study, told The Scientist. Susan Rosenberg's lab devised a novel assay detection system and genetically programmed wild-type E. coli cells to glow green in the presence of a DNA double-strand break (DSB). This technique provided the first direct data on the number of DSBs actually occurring in prokaryotic cells. Previous research has estimated DSBs occurred in every chromosome generation. Rosenberg and her colleague, however, place the rate at approximately one...