ARIZONA MEDICAL CENTER 
TUCSON, ARIZONA 85724 
THE UNIVERSITY OF ARIZONA 
COLLEGE OF MEDICINE 
DEPARTMENT OF MICROBIOLOGY 
(602) 626-6061 
September 22, 1978 
Dr. Donald Fredrickson, Director 
National Institutes of Health 
Bethesda, Maryland 20016 
Dear Dr. Fredrickson: 
I have read and agree with the majority of the proposed changes in the 
Proposed Revised Guidelines for Recombinant DNA research. I feel that 
the proposed changes are quite justified by the very low liklihood of 
eucaryotic gene expression in ,![. coli , by the inability of such gene 
expression, if it did occur, to produce injurious effects, and by the 
inability of E. coli K-12 to colonize the human gastriointestinal tract. 
I would suggest that the conditions for shotgun cloning of mammalian and 
bird DNA should be changed from P2-EK2 to P2*-EK2 or P3-EK1. The same 
choice is allowed for experiments 6, 12, 13, 19, 25, 42 and 43 and it 
seems, perfectly consistant that a similar combination be allowed here, 
i.e. increasing physical containment should permit a reduction in 
biological containment. 
Sincerely yours. 
David W. Mount, Ph.D. 
Associate Professor of 
Microbiology 
DWM : kb. 
[A-292] 
