RpcfefelTer 
University )£ 
THE ROCKEFELLER UNIVERSITY 
1230 YORK AVENUE • NEW YORK, NEW YORK 100 21 
December 10, 1979 
Dr. Donald S. Fredrickson, 
Director 
National Institutes of Health 
Bethesda, Maryland 20205 
Dear Dr. Fredrickson: 
As the National Institutes of Health is presently con- 
sidering an important revision to the Guidelines for Research In- 
volving Recombinant DNA Molecules, I would like to register my firm 
support for the proposed exemption of E. coli K12 host-vector sys- 
tems. Since the widespread implementation of recombinant DNA technology, 
we have witnessed quite remarkable improvements in our understanding 
of gene organization and function in eukaryotes. There is no longer 
any doubt that this line of research promises extraordinary clinical 
benefits and the technology remains one of our most powerful tools for 
basic biomedical research. Accumulated evidence attesting to the 
safety of E. coli K12 host-vector systems makes it obvious that the 
exemption of many experiments is overdue. I applaud the RCA Working 
Groups realization of this inappropriate regulation and their attempts 
to correct the Guidelines. I hope for a speedy implementation of the 
proposed revisions. 
Sincerely, 
Since 
Michael W. Young 
Assistant Professor 
and University Fellow 
The Rockefeller University 
MWY/pb 
[ 440 ] 
