Conjugal transfer and autonomous replication of some episomes occurred normally in a recombination-deficient (Rec
-) mutant of
Escherichia coli K-12. Transduction with phage Plbt of an R factor also occurred normally in this Rec
- mutant, but complete or abortive transduction with Plbt of chromosomal genes did not occur. In contrast, transduction of galactose genes by phageλdg occurred in the Rec
- bacteria as frequently as in the Rec
+ strain. It was shown that phage Plbt does not grow at all on the Rec
- bacteria. Recombination between two different R factors, two mutants of phage y and two mutants of phage T4 occurred normally in the Rec
- bacteria, but did not give a Rec
+ phenotype to the host bacteria. Colicinogenic factor I made the Rec
- host bacteria more resistant to ultraviolet light but the colicinogenic strain was still infertile in the crosses with the Hfr Brains of E. coli K-12.
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