THE JOHNS HOPKINS UNIVERSITY 
SCHOOL OF MEDICINE 
DEPARTMENT OF MICROBIOLOGY 
December 11, 1979 
725 N. WOLFE STREET 
BALTIMORE, MARYLAND 21205 
Dr. Donald Frederickson 
Director of the N.I.H. 
Bethesda, Maryland 20205 
Dear Dr. Fredrickson: 
I wish to express my firm support for the proposed revision of the 
Guidelines on Recombinant DNA Research appearing in the Federal Register for 
November 30, 1979. I am especially in agreement with section III-O on page 
69218 proposing a major decrease in the containment requirements for experi- 
ments using E. coli host vector systems. Two things make me believe that this 
significant lightening of restrictions is reasonable: 1) no dangerous 
recombinant organism has surfaced, and 2) recent work with translocatable 
elements and plasmids suggests that so-called illegitimate recombination events 
occur much more widely in bacteria (and probably in higher cells) than was 
previously appreciated. Also, one cannot underplay the rapid strides in our 
understanding of cellular activities that have come about through the 
application of recombinant DNA techniques. 
Thus, in my opinion, the proposed revision is both reasonable and timely. 
I fully anticipate that, as a result of the change, recombinant DNA research 
will be greatly facilitated and stimulated. 
Sine 
Hamilton 0. Smith 
