HARVARD UNIVERSITY 
The Biological Laboratories 
16 Divinity Avenue 
Cambridge, Massachusetts 02138 
January 3, 1979 
Dr. Donald S. Fredrickson 
Dir ector 
National Institutes of Health 
Building 1, Room 124 
Bethesda, Maryland 20205 
Dear Dr. Fredrickson: 
I am writing in support of the "_E. coli K-12/P1 r ecoirmendation" 
(Federal Register 44^, 69235) for revision of the NIH guidelines 
on recombinant DNA experiments. As a microbiologist I find it 
unreasonable to believe that the cloning of foreign DNA in _E. coli 
K-12 under the restrictions of the recommendation could pose any 
public health hazard. Indeed, despite several years of accumulated 
experience (and much fruitful accomplishment) , the scientific community 
has uncovered no demonstrable hazard in recombinant DNA work. 
S inc er ely your s , 
Richard Losick 
Professor of Biology 
RL/vth 
[ 640 ] 
