MINUTES OF MEETING - December 6-7 
13 
meetings ago. Dr. Talbot, hcwever, noted that two meetings ago 
the RAC made their recommendation and the Director, NIH, sub- 
sequently promulgated his decision on this issue. Dr. Talbot 
said that if further revision is to be recommended by the RAC, 
the proposed revision should first appear in the Federal Register 
for a new period of public comment. 
Dr. Rowe said he had suggested at the May 1979 meeting that 
experiments involving insertion of recombinant DNA molecules into 
tissue culture cells be exempted from the Guidelines, provided 
that if eukaryotic viral genes were involved, less than one- 
fourth of the total viral genome could be used. He said that in 
the discussion at the May 1979 RAC meeting, rather than press the 
issue of whether one-fourth of a virus could generate a biohazard- 
ous agent, he deleted this section from the proposal so that the 
final recommendation as passed by the RAC and subsequently 
accepted by the Director, NIH, allows no component derived from 
a eukaryotic virus under this exemption. Dr. Rcwe had since 
polled several eminent virologist and forwarded their responses 
to the RAC. They favored allowing one-fourth or less of the 
genome of a eukaryotic virus within this exemption. Dr. Novick 
stated that at a previous meeting Dr. Baltimore produced a 
scenario in which two ends of an RNA tumor virus in the right 
context could replicate. Dr. Baltimore said that he had said 
the ends of the viral genome have all the signals required for 
replication, but reverse transcriptase is also required and 
must be provided by a helper virus. Dr. Novick asked if rescue 
of defective viruses was uncommon. Dr. Baltimore said that it 
is not uncommon in the laboratory, but the co-maintenance of a 
defective and non-defective virus in nature is very rare. 
Dr. Gottesman said that an issue is whether the addition of one 
quarter of one virus, one quarter of a second virus, and one 
quarter of a third virus to the same culture should be per- 
mitted under this exemption. She said the RAC specifically 
required those situations be reviewed on a case-by-case basis. 
Dr. Gottesman said that the TK piece of Herpes Simplex Virus is 
very useful and that this situation should be handled separately. 
However, all viral combinations should not be permitted. 
Dr. Baltimore said he would like to modify Dr. Rowe's proposal 
as he finds the restriction to one quarter of a virus to be 
artificial and extremely low. He proposed to add to the 
exemption: 
"Or that contain a demonstrably defective genome of a 
eukaryotic virus." 
[ 406 ] 
