Linkage map of Salmonella typhimurium, edition VII

The genes of Salmonella typhimurium LT2 are located on a closed circular linkage map. The original map was determined by interrupted mating in F-mediated conjugation. More recent data are derived primarily from bacteriophage P22- and P1-mediated transduction and frome gene cloning and molecular analysis. The circular linkage map is set at 100 U to correspond with the 100-min map of Escherichia coli K-12. In this seventh edition of the linkage map, 750 genes are listed, with 680 of these located on the map and the remaining 70 being genes for which mutant alleles are known or which are cloned but not yet mapped. The linkage maps of S. typhimurium and E. coli K-12 are very similar. A plasmid, pSLT, present in all strains of LT2 except those from which it has been intentionally eliminated can carry mutations which affect the phenotype of the cell. Genetic materials and methods relevant to analysis of S. typhimurium are presented. Wild-type and mutant forms of transposons, primarily Tn5 and Tn10, and bacteriophage Mu enable new approaches to determination of gene expression and to isolation and analysis of genes. A collection of strains carrying transposon insertions around the chromosome of S. typhimurium has been assembled and is available from the Salmonella Genetic Stock Centre. S. typhimurium can be transformed with plasmid DNA by calcium chloride methods or by electroporation. A set of strains carrying F-prime factors with E. coli chromosome fragments, and with Tn10 insertions, is described.