123 HUNTINGTON STREET BOX 1106 NEW HAVEN, CONN. 06504 (203) HXXXX20X 
789-7258 
Founded 1875 
Putting science to work for society 
10 May 1978 
Gentlemen: 
The attached letter from Dr. M.-D. Chilton and her colleagues outlines two 
recombinant DNA experiments that involve the plant pathogen Agrobacterium 
tumefaciens . The first is designed to assess risks and the second to assess 
potential agricultural benefits. These experiments are now prohibited by the 
current NIH Guidelines. 
A recent workshop on agricultural pathogens recognized that there is 
natural exchange of chromosomal DNA between A. tumefaciens and E. coli K12 and 
agreed on reducing physical containment for Intact plants as host-vector systems 
for recombinant DNA to P2. These recommendations were adopted by the Recombinant 
DNA Advisory Committee. The revised Guidelines now under study would therefore 
permit these experiments. However, several months are likely to pass before the 
revised Guidelines are adopted, and there is no assurance that they will be 
adopted in their present form. 
I am therefore proposing that permission be given to carry out these experi- 
ments in the Plant Disease Research Laboratory, Frederick, Maryland. Dr. Emmett 
Barkley tells me that the secondary containment in this laboratory is equivalent 
to P4. It lacks glove boxes for primary containment but these are designed to 
protect workers from human pathogens and so would not usually be appropriate in 
a plant laboratory. 
I believe that the information to be gained from these experiments will be 
useful and important for assessment of the risks and benefits to agriculture 
from recombinant DNA technology. 
Sincerely , 
Peter R. Day, Head 
Department of Genetics 
PRD/ebb 
end. 
(l)Dr. J. Nielson, Acting Director (3)Dr. D.S. Fredrickson, Director 
Science & Education Administration NIH, Bethesda, MD 20014 
USDA, Washington, D. C. 20250 
(2)Dr. R. C. Atkinson, Director 
NSF-Washington , D.C. 20550 
[Appendix A — 301] 
