6 
6. Several commentators were concerned about certain definitions 
on p. 28 for the characterized clones of DNA recombinants 
derived from shotgun experiments. The concept of "free of 
harmful genes" was found to be troubling to many. Would the 
committee care to review that phrase? Further, what is the 
committee’s response to our adding another clause to footnote 4 
to make it read as follows: "The terms 'characterized' and 
'free of harmful genes' are unavoidably vague. But, in this 
instance, before containment conditions lower than the ones used 
to clone the DNA can be adopted, the investigator must obtain 
approval from the granting agency as guided by the advice of 
its Recombinant Advisory Committee ." Does the committee consider 
this certification an appropriate and feasible function or would 
it suggest alternative mechanisms for this responsibility? 
Could the committee perform this function for any larger group 
of scientists other than those supported by NIH if that task 
befell it? Could any committee or series of them handle this 
problem? 
7. On p. 30 the committee has listed containment levels for the 
use of animal viruses as the foreign source for DNA. In this 
section of the guidelines it is not clear whether it was the 
intent of the committee to permit experiments with cDNA from 
RNA tumor viruses. Was this the committee's intent? Would 
the committee object to our making explicit that only cDNA from 
RNA viruses which have been shown to be non-oncogenic can be 
used in DNA recombination experiments? 
8. On pp. 30-31 of the proposed guidelines are recommendations 
concerning eukaryotic organelle DNA as the foreign source. 
There is concern about the potential contamination of purified 
eukaryotic organelle DNA with viral DNA. I would appreciate 
the committee's comment on the recommendation that embryonic 
primate material be permitted to be used at P3 + EK1 or P2 + EK2 
and that non-embryonic primate material require P3 + EK2. 
I would also appreciate the committee's opinion on a require- 
ment in this section that the mitochondria be isolated prior 
to DNA extraction, as a further means of reducing the hazard 
of viral contamination. 
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