UNIVERSITY OF CALIFORNIA, SAN FRANCISCO 
BEfUCELEY • DAVIS • IRVINE • LOS ANGELES • RIVERSIDE • SAN DIECO • SAN FRANCISCO 
SANTA BARBARA • SANTA CRUZ 
SCHOOL OF MEDICINE SAN FRANCISCO. CALIFORNIA 94143 
DEPARTMENT OF BIOCHEMISTRY AND BIOPHYSICS (41 5) 666-4324 
December 13, 1979 
Dr Donald Frederickson 
Director, 
National Institutes of Health 
Betheseda, Maryland 20205 
Dear Dr Frederickson, 
This is to urge formal adoption at the earliest possible time of the 
revised guidelines as published in the Federal Register for Friday, 
November 30 (pages 69210-69251). It is now exceedingly clear that the 
£. coli K-12 host-vector systems carrying recombinant DNA do not give 
rise to pathogenic variants. Although I would strongly prefer exemption 
of these experiments from the Guidelines altogether, the present revision 
represents a significant simplification in a bureuacratic maze that not 
only now appears pointless, but indeed is significantly impeding the 
progress of useful and important studies. 
Sincerely yours 
Keith 1 . Yamamoto 
Associate Professor of Biochemistry 
[ 463 ] 
