Meso-tartrate resistance and phylogenetic relationships of biotypes ofSalmonella typhimurium

Abstract

SUMMARYMeso-tartrate utilizing and resistant (mT+) recombinants were produced readily in transductions from an mT+donor strain to 42 naturally occurringmeso-tartrate non-utilizing and sensitive (mT−) recipient strains ofSalmonella typhimurium, and were produced, sometimes as frequently, in interbiotype crosses between different pairs of strains from the mT−biotypes 2, 18, 26 and of the FIRN group (biotypes 30 and 32). These findings suggested that the sites of themtamutations were independent in strains from the different mT−biotypes and were in agreement with their probable different lines of descent. Intrabiotype crosses indicated genetic homogeneity among strains of biotype 26 and among strains of biotype 30; on the other hand, they suggested that in each of the biotypes 2, 18 and 32, a minority of strains hadmtamutations present at different intragenic sites from those of the majority of strains. The derivations of the strains of the minority types are discussed.