title: Method for the isolation of Escherichia coli mutants with enhanced recombination between chromosomal duplications.
abstract: A method is described for the isolation of Escherichia coli mutants that show increased recombination between a pair of chromosomal duplications. These "hyper-rec" mutants display a variety of secondary phenotypes. I have isolated a large number of hyper-rec mutants and found them useful in screening for mutants that accumulate labeled DNA fragments after short pulses with [3H]thymidine. The mutants so recovered include ones that are defective in deoxyribonucleic acid ligase, deoxyribonucleic acid polymerase I and its associated 5' yields 3' exonuclease, and a group of mutants, dnaS, that accumulate abnormally short Okazaki fragments. Evidence is presented that suggests that the lac-att80 segment of the chromosome cannot be inverted.
mesh_terms: D002876:Chromosomes, Bacterial / Q000502:physiology*; D003434:Crossing Over, Genetic; D004256:DNA Polymerase I / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism / Q000502:physiology; D005796:Genes; D007785:Lactose / Q000378:metabolism; D008722:Methods; D009154:Mutation; D011118:Polynucleotide Ligases / Q000378:metabolism; D011995:Recombination, Genetic
chemical_list: D004269:DNA, Bacterial; D004256:DNA Polymerase I; D011118:Polynucleotide Ligases; D007785:Lactose