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DR. FREDRICKSON: I think we may be testing the blood sugar levels 
of certain members of the Committee. 
MR. HUTT: You certainly haven't clarified that for me, Walter. 
(Laughter . ) 
PROFESSOR ROSENBLITH: There was a whole wasted education for you. 
(Laughter . ) 
DR. FREDRICKSON: Dr. Sinsheimer, did you have a comment? 
DR. SINSHEIMER: I have two points, and one is very similar to the 
one I made before, when you talk about a probability of 10 -16 , or less than 
10 -16 , that is meaningless. What it means is that something that happens in 
the intestine of somebody who is on antibiotics or something is going to be 
the determining factor, not a 10 “ 16 , because some other thing will happen 
much more frequently than that. 
The other point, and I keep harping on the Chang and Cohen experiment, 
but let us just say what was done. What was done was to take a piece of 
DNA from a microorganism which had a piece of mitochondrial DNA in a 
plasmid, cut that plasmid with Eco R1 , so that you had some Eco R1 frag- 
ments, take some other Eco R1 fragments from another plasmid, mix those, 
provide them to a bacterium which had been treated with calcium and heat 
shock, and had in it Eco R1 , and find that lo and behold! you have got a 
plasmid put back together from those two pieces inside that microorganism. 
That is fine, but — 
DR. HELINSKI: That is not entirely accurate as a description of the 
experiment. This was an in vivo cleavage and ligation, and you described 
it as something that you did outside the cell and had the cells take up. 
DR. SINSHEIMER: I don't think you are right. I read that jiaper last 
night to be prepared. There were in vivo recombinations, but the ones with 
eukaryotic DNA were in vitro mixtures added to the cell. We can look up 
the paper, but if I can finish the point, that experiment simply doesn't 
tell me what the probability of that event taking place is, and if it is so 
very--then in that case I really don't know what to make of it. It is 
a little bit — if I may make an analogy that I know Dr. Davis won't like — it 
is a little bit like saying that because plutonium atoms are made in nature 
we don't have to worry about it. 
DR. HELINSKI: I am sorry, that what? 
DR. SINSHEIMER: That because plutonium atoms are in fact made in nature 
we don't have to ever worry about plutonium. 
DR. HELINSKI: I would like to attempt to clarify this. I don't think 
that these transformation conditions that are commonly used for E. coli are 
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