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unpalatable type of scenario, and we had better be very, very careful until 
we have some more data. I think the EK2 and even the EKl data are very 
powerful in relation to putting polyoma or almost any other viral genome into 
prokaryotes . 
DR. FREDRICKSON: That is the first part of the question. 
DR. GINSBERG: The second part of the question, I suppose you will 
answer the same way. 
DR. ROWE: Yes, I think so. The use of polyoma virus as a vector, 
I cannot myself come up with a meaningful risk scenario for either people 
or mice. So I will say on that one, that was not really my initiative, 
that was more the sense of the Committee. 
DR. FREDRICKSON: Dr. Rowe, before Dr. Skalka gives her comment, would 
you answer the question for me — I am not certain now: if you use polyoma as 
a vector, say, for putting the mouse hemoglobin gene in the mouse cell, and 
polyoma normally resides in the mouse, what is the containment level now? 
What will it be set at? 
DR. ROWE: It will be P3. I think it is P3 now. 
DR. GINSBERG: P3+EK3? 
DR. ROWE: No, it is polyoma as a vector. 
DR. GINSBERG: Oh, polyoma as a vector, I am sorry. 
DR. ROWE: There is the question that polyoma in mouse cells is known 
to pick up some mouse cellular DNA sequences covalently linked and carried 
in defective particles. It can make its own recombinant DNA and normally 
does in a certain proportion, a fairly large proportion of particles. SV40 
does the same in monkey cells, certainly in nature as well as in the labora- 
tory, because it is a monkey virus. 
DR. FREDRICKSON: Just to be sure — I am not trying to make a point, but 
I want to be sure: polyoma virus is normally found in mice in the laboratory? 
DR. ROWE: Only in' mice in nature, yes. 
DR. FREDRICKSON: But in order to do this experiment you have to go in 
P3 . 
I wonder, Dr. Skalka, if you would make your comment, then I know 
others here would like to question Dr. Rowe. Dr. Skalka is from the Roche 
Institute of Molecular Biology. 
DR. SKALKA: My comments don't reflect the Roche Institute, but my own. 
But they do in fact reflect the opinions of Drs. Paul Berg and David Balti- 
more as reflected in these letters that you have. They also reflect the 
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