CALIFORNIA INSTITUTE OF TECHNOLOGY 
PASADENA. CALIFORNIA 01125 
Department of Chemistry 
December 13, 1979 
Director 
National Institutes of Health 
Bethesda, Maryland 20205 
Dear Dr. Frederickson : 
I write to support the proposal, as stated in the Federal 
I Register of November 30, 1979, that the NIH Guidelines be revised 
so that in recombinant DNA experiments using E. coli K12 as a host, 
PI physical containment will be sufficient and the requirement for 
j an MUA submitted to the NIH is replaced by the requirement that the 
local IBC be informed. 
I think that in this respect, the revised Guidelines are just 
I right. E. coli K12 cannot grow and propagate recombinant DNA in any 
I environment outside of special culture media in a laboratory. The 
requirement that each investigator inform his local IBC of his research 
; plan is sufficient to insure that the investigator and the IBC will 
! consider any unusual situations that might prompt further analysis 
of the safety for any particular experiment. The only slight danger 
' that I can see is that a biologically active eukaryotic protein might 
; be made in E. coli K12 and have a short term adverse effect on an 
experimenter who had accidentally contaminated himself. The requirement 
I for PI containment and for the review of such possible hazards by the 
local IBC should be sufficient protection against this rather improbable 
risk . 
We have had a lot of experience with recombinant DNA in the last 
f few years and we have come to realize that the risks have been 
exaggerated. The proposed new Guidelines are a very sensible step 
forward. By freeing scientists from unnecessary red tape, and admin- 
istrative delays in doing experiments, they will appreciably accelerate 
the progress’ of research and the realization of its benefits. 
Sin 
Norman Davidson 
ND/mca 
[ 477 ] 
