UNIVERSITY OF CALIFORNIA, LOS ANGELES 
BERKELEY • DAVIS • IRVINE • LOS ANCELES • RIVERSIDE • SAN DIEGO • SAN FRANCISCO 
SANTA BARBARA • SANTA CRUZ 
DEPARTMENT OF MICROBIOLOGY 
COLLEGE OF LETTERS AND SCIENCE 
LOS ANGELES, CALIFORNIA 90024 
December 20, 1979 
Dr. Donald S. Frederickson 
Director, National Institutes of Health 
Bethesda, Maryland 20014 
RE: Recombinant DNA Guidelines and Federal Register, 
November 30, 1979 
Dear Dr. Frederickson, 
I support the proposed changes in the NIH Guidelines as 
described in the Federal Register of November 30, 1979. The 
reduction in containment requirements recommended are entirely 
consistent with the demonstrated safety of EL col i K12 host-vector 
systems. In addition, these revised Guidelines should allow for 
more rapid advances in nucleic acid research and should decrease 
the associated costs. 
Sincerely 
Arnold Berk, M.D. 
Assistant Professor 
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