Abstract
Three-point transduction analysis was employed to determine the sequence of four structural and two regulatory methionine genes (metA, B, F, HandmetI, J, respectively) on two apparently adjacent transduction fragments inSalmonella typhimurium. These fragments were subsequently orientated with respect to each other and the rest of the linkage map by the analysis of recombinants obtained in conjugation experiments. The following clockwise sequence of genes is proposed: -metJ-metB-metF-argF-thi-purD-metA-metI-metH-. The bearing of these results on the regulation of themetB–FandmetA–Hclusters is discussed.