Baylor College of Medicine 
DEPARTMENT OF CELL 8i0L0GY • 713 521-4701 
September 1, 1978 
Dr. Donald Fredrickson 
Di rector 
National Institutes of Health 
Bethesda, Maryland 20016 
Dear Dr. Fredrickson: 
I have received a copy of the Proposed Revised Guidelines for 
Recombinant DNA Research (Federal Register £3, 33042-33178) and 
I would like to question the following. 
The proposed containment for shotgun recombinant DNA work on 
non-primate mammals and birds is P2 + EK2, yet for cold-blooded 
animals, plants and many of the RNA and DNA viruses it is P2 + 
EK2 or P3 + EK1 . Is there a sound scientific basis for not 
also allowing non-primate and bird recombinant DNA work to be 
also carried out under P3 + EK1? The restriction to the use of 
only P2 + EK2 is not a trivial point, since many experiments 
using EK1 vectors are extremely difficult, indeed some simply 
impossible (e.g., those involving lysogenic \ systems) in an 
EK2 system. In particular, I find it difficult to see why 
segments of some transforming viruses may be cloned under P3 + 
EK1 conditions, yet DNA from a non-primate mammal or bird in 
which any one sequence is diluted out at least one in 10$ with 
the other sequences present cannot be carried out under these 
same conditions. 
It would be greatly appreciated if you could bring this sugges- 
tion to the attention of the Advisory Committee. 
Sincerely yours. 
/gbc 
[A— 77] 
ST. LUKE S EPISCOPAL HOSPITAL, 25TH FLOOR • TEXAS MEDICAL CENTER • HOUSTON, TEXAS 77030 
*V»CE • 3NIO' q1 
