UNIVERSITY OF CALIFORNIA, SAN FRANCISCO 
BERKELEY • DAVIS • IRVINE • LOS ANGELES • RIVERSIDE • SAN DIEGO • SAN FRANCISCO 
SANTA BARBARA • SANTA CRUZ 
SCHOOL OF MEDICINE 
DEPARTMENT OF BIOCHEMISTRY AND BIOPHYSICS 
SAN FRANCISCO, CALIFORNIA 94143 
(415) 666-4324 
December 19, 1979 
P.Z. O' Farrell 
Department of Biochemistry 
and Biophysics 
University of California 
San Francisco, CA 94143 
Dr. Donald Fredrickson 
Director of the N.I.H. 
Bethesda, MD 20205 
Dear Dr. Fredrickson: 
I wish to support the proposed revisions of the recombinant DNA 
guidelines described in the Federal Register/Vol. 44, No. 232, November 
30, 1979. I especially agree with Section III-O which proposes to allow 
experiments using jE. coli K12 host vector systems to be carried out at 
the Pi level containment level (except for prohibited or exempt experi- 
ments) . In addition, I feel the guidelines are still too stringent in 
the requirement to obtain prior approval of the IBC for experiments to 
express eukaryotic genes in E coli K12, and would also like to suggest 
that there should be no required registration of Pi experiments. 
Sincerely yours 
Patricia Z. O'Farrell, Ph.D 
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