Abstract
We present conclusive evidence for the chromosomal location of the lac gene in a lactose-fermenting Salmonella litchfield strain (AO Lac+). Two Hfr strains constructed from AO Lac+ had abilities to transfer the lac gene to S. typhimurium LT2 at relatively high frequencies. Detailed characterization of the transconjugants suggested that the lac in AO Lac+ was located on the host chromosome between galE (18min) and trpB (34min). Transduction experiments using P22 phage showed that the lac was cotransduced with gal, but not with trpB. These results clearly indicate that the lac gene is located at a position near 18min of the linkage map of Salmonella.
