109 
DR. FREDRICKSON: Thank you. 
Now, in order to hear from the other witnesses, we will omit ques- 
tioning, and proceed to Dr. Wright, who will also have five minutes. 
MR. HELMS: Will we get another opportunity for questioning these 
witnesses? 
DR. FREDRICKSON: I think at the end of the three presentations, unless 
you would — 
MR. HELMS: I have a question, but it will wait. 
DR. FREDRICKSON: All right. We will return to that after Dr. Wright. 
Dr. Wright, your time is beginning. 
DR. WRIGHT: Well, again, I would just like to make a few brief comments 
I do not have a prepared statement. 
There are several areas that I think are very important for the risk- 
assessment process in general, about which there appears to be very little 
consensus at present, and I just want to list these. 
First of all, on the pathogenicity of E. col i , I think the remark was 
made that it is not a very good pathogen. Well, i f we look at the responses 
to the draft Environmental Impact Statement, Appendix K, page 63 in the 
thicker of the two Yellow Books, we have the following statements. "E. col i 
has, over the past eight years, emerged as one of the primary causes of 
gastroenteritis and diarrhea. * * * E. col i is responsible for nearly 100 
percent of upper urinary tract infections, including severe cases where the 
kidneys are involved, and most cases of cystitis. This type of infection is 
independent of the capacity of E. col i to colonize the human gut." I refer- 
red to that this morning. " E. coli is the etiologic agent for 30 to 40 
percent of the cases of sepsis (often fatal.) This is also independent of 
the ability of E. coli to colonize the gut." 
Second, on the use of antibiotic resistance genes as markers, the 
apparent consensus of the Recombinant DNA Advisory Committee is that such 
genes can be used at the HV1 and HV2 levels, but not at the HV3 levels 
because of the problem of generating possible selection advantage if DNA 
used at that level somehow escaped and became available in the environment. 
Well again, other scientists apparently disagree. Sidney Brenner, of 
the Cambridge Molecular Biology Lab has flatly said that antibiotic resis- 
tance markers should be banned. This also appears to have been a matter of 
some debate at the Falmouth workshop. 
Finally, there appears to be very little consensus about what is meant 
by the criterion used in the revised definition in the Guidelines of a phenom 
enon that "occurs in nature." Apparently the Committee accepts Dr. Cohen's 
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