Abstract
Recombination deficient mutants of Staphylococcus aureus were isolated and found to have properties similar to those of recombination deficient Escherichia coli. In addition, one Rec- mutant was found to be defective in the restriction and modification of DNA. There is a marked reduction (104 fold) in recombination between penicillinase plasmids in the Rec- mutants suggesting that these elements do not encode an efficient recombination system. There is, however, a demonstrable residuum of interplasmid recombination; evidence is lacking on whether this residuum is a plasmid or host function. In the absence of the generalized host recombination system it was possible to demonstrate that interplasmid recombination occurs during vegetative bacteriophage growth and is presumably mediated by a phage determined recombination system.