100 
DR. FREDRICKSON: I just want to be sure that Dr. Kelly's question is 
answered well for those on the committee who may also have the same ques- 
tion. I think his question is that it is not then changing the infectivity 
or infectiousness of _E. coli , but that we would be introducing through them 
chimeric forms of new genetic material, right, Dr. Berg? Let us be sure 
that there is no question about that. 
DR. SINSHEIMER: May I speak to that? 
DR. FREDRICKSON: Yes, Dr. Sinsheimer? 
DR. SINSHEIMER: I have no technical information to contribute, but I 
share the concern that Dr. Petersdorf, who knows much better than I, has 
pointed out, that we are pretty resistant to most organisms, most likely by 
virtue of selection. Indeed, we all know what has happened to the Hawaiian 
Islanders, et cetera, when they were exposed to organisms novel to them. 
They were decimated. 
The possibility of generating novel pathogens through the introduction 
of eukaryotic genes into prokaryotes, I think, cannot be neglected. We 
know, for example, that there are many viruses indigenous to prokaryotes 
which ordinarily are of no consequence to us or other eukaryotes because 
they lack, for example, the means for expression, the proper control 
sequences . 
I don't see how we can know at this time that they couldn't acquire 
such control sequences from these chimeric organisms, and thereby become 
a potential hazard. 
DR. PETERSDORF: But where virgin populations have been studied, that 
really have been decimated by new organisms, they have been almost entirely 
viruses. I think that only the totally germ-free pigs that are being pro- 
duced are decimated by bacterial infections. Sure, there are bacterial 
epidemics, but I am not at all sure that in the recent past this has been 
a major problem with the populations in Hawaii or in Alaska among the 
Eskimos, where the problem has been almost entirely due to viruses. I 
think Dr. Melnick again knows more about that. 
DR. FREDRICKSON: Mr. Hutt? 
MR. HUTT: We come back to the question again of the burden of proof. 
I think this is fairly critical. I agree with Dr. Callahan, that the 
public is quite clear that far from being a burden on them to establish 
that there is a hazard, they look at it that it is the burden on the field 
of science that wants to proceed in these inquiries that there is no hazard. 
Until that burden is satisfied one way or another, with either the physi- 
cal or biological containment concepts that we talked about today, I don't 
think the public will feel very good about your statements or any expert's 
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