STANFORD UNIVERSITY 
STANFORD. CALIFORNIA 94305 
DEPARTMENT OF BIOLOGICAL SCIENCES 
September 13, 1978 
Dr . Donald Fredrickson 
Director, National Institutes of Health 
Bethesda, Maryland 20014 
Dear Dr. Fredrickson: 
On September 12, 1978, the Working Group on Prokaryote Host-Vectors Other 
Than Eh coli K-12 of the Recombinant Advisory Committee met at Stanford. 
John Spizizen is preparing a full report of our recommendations to be 
submitted to RAC. However, one of our recommendations can be effected by 
making a small change in the wording of the Proposed Revised Guidelines. 
As this is a minor modification that clarifies the intent of the Proposed 
Revised Guidelines, we recommend its inclusion at this time. 
Proposal : 
Section I-E-3 of the Proposed Revised Guidelines should be amended to read 
as follows : 
I-E-3. Those that consist entirely of DNA from a prokaryotic host, includ- 
ing its indigenous plasmids or viruses, when propagated only in that host 
(or closely related strain of the same species) or which have been trans- 
ferred to another host by known physiological means ; also those that con- 
sist entirely of DNA from a eukaryotic host, including its chloroplasts , 
mitochondria, or plasmids (but excluding viruses) , when propagated only in 
that host (or a closely related strain of the same species) . 
Justification : 
Addition of the proposed clause will exempt the following type of experiment: 
An Eh coli strain is constructed in which a chromosomal gene of Eh coli has 
been enzymatically joined to plasmid DNA; this plasmid is then transferred 
by conjugation into another bacterial host that is not on the Director's List 
of bacteria that exchange with Eh coli . 
It seems logical that this experiment should be exempt, because it involves 
natural genetic exchange between two organisms both of which are exempt. 
The Eh coli donor is exempt because it represents a gene combination that 
could easily arise by natural means. As the transfer can also occur naturally 
the same statement applies also to the second host carrying the plasmid. 
[A— 140] 
