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and creativity. Unfortunately, some portions of The Guidelines, 
but particularly the implementation of The Guidelines, are 
already having that effect. I urge you to be on guard against 
that outcome. 
I have from time to time reflected on my participation in 
raising the recombinant DNA issue in 1974. Considering what 
we knew then and what we perceived as the risks, I don't see 
how I or any of us could have done otherwise. Had we been 
privy to the information, discussions and experience available 
today, that action would surely not have been taken. Opponents 
of recombinant DNA research, or those wishing to restrict its 
applications, can no longer cite that document as an expression of 
present day concerns. 
There are several specific comments about PRG-NIH that 
I want to register; hopefully they will be helpful to you in 
arriving at the final form of this version of The Guidelines. 
1. Your decision to remove a large number of innocuous 
experiments from the purview of The Guidelines is a wise one; 
such experiments have never been the subject of concern even 
amongst those who opposed the research. I am also in general 
agreement with the reduction in containment requirements for 
most experiments using the EK host-vector systems. The large 
body of experience gained during the past four years and the 
advice of infectious disease experts, epidemiologists and 
evolutionists suggests that the earlier concerns were unwarranted. 
2. Earlier I had suggested that PRG-RAC's recommendations 
for experimentation with recombinants containing animal or plant 
virus DNAs needed to be reevaluated. The present recommendations, 
drawn from the US-EMBO workshop and review committee's reports, 
are more realistic, reflecting a different assessment of the 
risk-benefit equation than was made four years ago. This line 
of experimentation should lead to important advances in 
understanding viral genome structure and function. In my 
view the potential benefits of permitting these experiments to 
proceed as now recommended far outweigh the hypothetical and 
rather unlikely risks; consequently, I support the recommendations 
in Section III-A-2. 
3. As I am involved in such research I'd like to comment 
at greater length on the containment requirements for ex- 
periments using animal virus vectors for cloning in mammalian 
cells (Section-C) . 
a) Infection of non-permissive cells results in a non- 
productive infection, but non-productive infections may also 
result from infection of permissive cells e.g. when 
[A-209] 
