Molecular Recombination in the Ligase Negative T4 Amber Mutant

Within the past years it has been established that parent-to-progeny recombination in T4 phage is accomplished by breakage and rejoining (Kozinski, 1961), followed by covalent repair in the continuity of the PNC (a list of abbreviations and idioms is presented later) (Kozinski and Kozinski, 1963). Evidence was also presented that an enzyme, ‘recombinase’, is needed for parent-to-progeny or parent-to-parent recombination (Kozinski, Kozinski, and Shannon, 1963; Kozinski and Kozinski, 1964). It was observed that addition of CM approximately 5 minutes after infection does not affect the semiconservative mode of replication of parental DNA but prevents the resulting hybrid DNA from undergoing breakages and exchanges with the progeny molecules. A refinement of the experiment, involving addition of CM at specific intervals after infection, indicated that concomitant with the inhibition of recombination by CM, there is an inhibition of an endonucleotic activity directed against the replicative form of T4 DNA. On this basis...