136 



late in the cycle. 



SPIEGELMAN: It has been shown that there is no new protein synthe- 

 sis for a period during which what is referred to as the vegetative DNA pool is 

 formed. There is a considerable amount of DNA synthesis prior to the appear- 

 ance of any phage specific protein. 



CARTER: This is high molecular weight DNA? 



SPIEGELMAN: This is high molecular weight DNA. 



POLLARD: Also Luria and Latarjet's radiation experiments showed 

 something like this. 



tion? 



DNA. 



CARTER: That DNA synthesis proceeds the period of protein forma- 



POLLARD: Yes. 



POTTER: What you are saying is that DNA synthesis requires only 



SPIEGELMAN: No, it does not mean that. All it means is that you do 

 not make mature phage simultaneously with DNA. 



MAZIA: Can we be sure that DNA produced during the first period is 

 phage DNA? This can mean merely that the pieces are being made. 



SPIEGELMAN: These pieces were big enough to participate in genetic 

 exchange. 



CARTER: How big are they ? 



SPIEGELMAN: I don't know, but they certainly cannot be at the nu- 

 cleotide level. 



CARTER: A problem arises because isn't it conceivable that low 

 molecular weight units can be transferred in and out of the polynucleotide chains 

 to give new sequences, and that actually you don't need to have a complete chain 

 to get a specific structure to bring about a specific event. 



KAMEN: Are you saying that you can start with one of these chains in 

 the Watson-Crick model and peel a hunk off the outside? 



CARTER: Right. 



CHARGAFF: The model then requires that you put in the complemen- 

 tary piece on the other side. This requires a lot of ingenuity. 



CARTER: The enzyme might do it. 



Well, I should like just to put the lid on this thing so we can get out of 

 here. 



There are a couple of consequences of splitting a polynucleotide chain. 

 The ratio of the end group to di-ester linkage is important in a variety of en- 



