Fertility-deficient E. coli K-12 mutants

Fertility-deficient and f2-r mutants of E. coli K-12 were studied. The above mutants were isolated following the nitrogen-mustard treatment of the E. coli K-12 Hfr and E. coli F1lac+-strains. Isolation of these mutants from F1-strains showed that mutations occur in the F-factor no matter whether it was in autonomous state or integrated in a chromosome.