title: Genetic methods for analysis and manipulation of inversion mutations in bacteria.
abstract: A number of genetic methods for the isolation, characterization and manipulation of large chromosomal inversions in Salmonella typhimurium are described. One inversion-carrying mutant is characterized in detail and used to demonstrate a number of unique genetic properties of bacterial inversions. --Contrary to expectation, it was found that large inversion mutations can be repaired by generalized transduction. The repair results from the simultaneous introduction of two wild-type transduced fragments into a single recipient cell. Homologous recombination between the two transduced fragments and the two inversion breakpoints causes the inverted segment to be reinverted. This results in regeneration of the wild-type orientation of this chromosome segment. Similar recombination events allow a large inversion mutation to be introduced into a wild-type strain; two transduced fragments from an inversion strain cause recombination events resulting in inversion of a large chromosome segment. --Genetic methods for mapping the extent of a large inversion mutation by generalized transduction are described and tested. The methods are operationally simple and allow good resolution of the two inversion breakpoints.
mesh_terms: D002874:Chromosome Mapping; D004260:DNA Repair; D005821:Genetic Techniques; D006641:Histidinol / Q000378:metabolism; D009154:Mutation; D009876:Operon; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D006641:Histidinol