Page three 
Dr. Donald Fredrickson 
August 31, 1978 
I know of no rational scientific basis on which one might predict that such 
inclusion and expression would be any more likely in shotguns of mouse as 
compared with yeast DNA. 
I have discussed this seemingly minor "detail" at some length because 
I believe it involves several important principles. One, is that every 
effort must be made to base the assignment of containment levels on something 
better than assumption. I believe that principle has not been applied in 
this instance. The second, questions the advisability of setting containment 
guidelines which, in effect, prohibit whole classes of experiments. Upgrading 
from P2 to P3, makes experimentation more difficult, but does not a priori 
rule out any specific class; upgrading from EK1 to EK2 makes whole classes of 
experiments (e.g. those requiring bacteriophage lambda lysogenization, or those 
utilizing the rich genetic library of Jh coli K12 strains) impossible. The full 
impact of this decision does not seem to have been thoroughly considered. 
I hope that these comments will be helpful to you — and I again hope that 
they will encourage your advisors to reconsider these classifications. I 
realize that if the Guideline revisions are to be adopted on a regular basis, 
each issuance will be somewhat less than perfect. Although I feel obliged 
to bring your attention to this detail, I would like to close by emphasizing 
the need for rapid implementation of the proposed revisions. 
■S' Department of Cell Biology 
AMS :pcp 
[Attachment published in Recombinant DNA 
Research , Volume 3, Appendix A, p. 9, 
September 1978.] 
[A— 70] 
