13 
This is really the extent of my remarks. I think the rest of the 
introduction section is fairly self-explanatory. It will be enlarged on 
to some extent by some of the later speakers. That is all I have to say, 
Dr. Fredrickson. 
DR. FREDRICKSON: Thank you. 
You have received, in addition to the comparison and the proposed 
revision of the definition, two other pertinent documents. There are a 
number of comments, but I would like to turn your attention to two in the 
Orange Book. One is a letter from Dr. Paul Berg, which is in the supple- 
ment, the second of the two orange volumes. Also, there is a long telegram 
from EMBO, which includes discussions on many matters, some of which bear on 
the definition. 
I would like to call at this moment on Dr. Maxine Singer from the 
scientific staff of the National Cancer Institute to expand just a little 
on Dr. Berg's letter, because it relates to certain matters touched upon by 
Dr. Littlefield as being subject to some change in the definitions of the 
Guidelines. Dr. Singer? 
DR. SINGER: Yes, the letter from Dr. Berg, as well as the report from 
the Committee of the European Molecular Biology Organization, point out that 
neither the original Guidelines nor the proposed revisions that we have in 
front of us gives any guidance on risk assessment for experiments that involve 
synthetic DNAs — that is, those experiments in which the foreign DNA that is 
joined to a vector has been prepared by chemical procedures. The need to 
include such experiments is pointed out by the comments I mentioned. The 
EMBO document is number 32 in the Orange Book. Also it is emphasized by the 
recent work of Itakura et al., which was recently published in Sc ience , and 
involved experiments with a synthetic gene for the hormone somatostatin. 
Paul Berg has addressed this problem, and you have that in front of 
you, but I will take the opportunity to note for you where his proposed 
wording changes make things different from the proposals of the Recombinant 
Advisory Committee. 
DR. FREDRICKSON: Excuse me, Maxine, maybe we can point out that Dr. 
Singer is referring to the second Orange Book, pages 82 to 84. She is 
going to point out some differences. 
DR. SINGER: If you look at the second sentence in the proposed re- 
wording of the definition, the suggested new wording says, "Recombinant 
DNA molecules are defined as molecules which have been constructed out- 
side of living cells by joining natural or synthetic DNA segments to DNA 
molecules that can replicate or be integrated into the genome of a living 
cell." This wording serves to place experiments with synthetic DNA fragments 
within the Guidelines. However, I would point out that the wording pro- 
posed by Dr. Berg has two additional significant changes from the wording 
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