FREQUENCY OF SPONTANEOUS BACTERIOPHAGE MUTANTS 



that lagged one reduplication behind. In either case, the clone will contribute to 

 the value Y2 and will be deducted from the value Y4. 



A correction should be made before comparing the results with the theoretical 

 expectation. The stocks of phage used to infect bacteria contained small, known 



TABLE 3. THE DISTRIBUTION OF MUTANTS IN INDIVIDUAL PLATES 



numbers of r and w mutants. Since we plated more than one burst per plate, 

 some of the mutant clones observed may have stemmed from bacteria infected 

 solely with one mutant particle. These clones ought to be eliminated (since they 

 derive from mutant particles originated in a mass lysate, where different condi- 

 tions obtain) but they cannot be recognized. The expected number of such "full 

 mutant" clones was 10. Assuming that a "full mutant" clone would be at least 

 as large as the minimum burst size, we eliminated from the experimeiits where 



145 



