Q.
A mutant strain of T4-bacteriophage R-II, fails to lyse the E.coli but when two strains R-II x and R−IIy are mixed then they lyse the E.coli. What may be the possible reason?
The enzymes required for lysing E. coli could not be synthesised by the mutant strain. Two different strains had cistrons for synthesizing two different enzymes which acted together.