Questions were raised by the public witnesses regarding the 
adequacy of the data employed to certify HV2 and HV3 systems. 
Concerns were expressed that all tests and performance criteria 
be made a matter of public record so that comments could be received 
prior to certification of a given system. Recommendations ‘were 
also made concerning the need for more extensive risk assessment 
studies, including those employing statistical analyses, and for 
NIH certification of HV systems developed by industry. 
Experim enta l Gu idelines 
The justification for the proposed revisions in the Experimental 
Guidelines section was presented by three members of the RAC. 
Dr. Donald Helinski described changes in containment levels 
for prokaryote and eukaryote DNA. He noted that the list of pro- 
hibited experiments has not been altered although the revised 
Guidelines do have a provision for exemption of specific exper- 
iments in each class. In the permissible class, most experiments 
will use E. coli K-12 as the host, although other HV1 Systems can 
be employed. Many categories have not been changed and are, in fact, 
even more stringent due to more rigorous requirements for certifi- 
cation of host vector systems. As examples of experiments that 
can be conducted at lower containment levels, Dr. Helinski mentioned 
shotgun cloning into E. coli K-12 of both non-primate mammalian 
DNA (from P3 + EK2 to P2 + EK2) and primate DNA (from P4 + EK2 
to P4 + EK1 ) . He pointed out that the proposed new definition of 
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