Genetic analysis of conjugational recombination in Escherichia coli K12 strains deficient in RecBCD enzyme

Conjugational recombination in Escherichia coli was investigated by comparing the effects of recN, recO, ruv and lexA mutations on the formation of recombinants in crosses with strains lacking RecBCD enzyme. The results presented reveal that recN and ruv mutations do not abolish residual recombination in a recB mutant, and have only a rather modest effect on recombination in recBC sbcA strains; in these respects they are quite different from recF, recJ and recO mutations. The differences between these two groups of genes are discussed in relation to the molecular exchanges needed to produce viable recombinants.