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 phage λ dg 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 λ 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 srains of E. coli K‐12.
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Toshiya Takano (1966) studied this question.