MEMORANDUM 
DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 
PUBLIC HEALTH SERVICE 
NATIONAL INSTITUTES OF HEALTH 
to :Dr. Donald S. Fredrickson date: September 25, 1978 
Director, NIH 
from :Dr. Philip Leder 
Chief, Laboratory of Molecular Genetics, NICHD, NIH 
subject : Proposed Revised Guidelines on Recombinant DNA Research 
1. The proposed revision of the Guidelines on Recombinant DNA 
Research is long overdue and in the right direction. Unfortunately, 
even the Revised Guidelines continue restrictions that I feel 
are excessive and scientifically unjustified. 
2. Specifically, the Guidelines that make the most sense are those 
that key restrictions to those employed in handling the most 
dangerous component of any given experiment. For example, if an 
experiment were being carried out with an organism that produces 
a toxin, the containment should reflect the containment necessary 
for that pathologic organism. All our expectations lead us to 
conclude that the recombinant would be less and not more dangerous 
than the original pathologic organism. 
3. While many of the regulations do not add to the safety of what are 
basically safe experiments, they do serve to inhibit the development 
of new and versatile vector systems. In our own case, we have simply 
not attempted to develop additional vector systems because the 
redundant safety testing program is too onerous, time-consuming and, 
in our opinion, not scientifically justified. There are many modifi- 
cations of vector systems that could increase their versatility. 
[A-383] 
