- 2 - 
We believe Dr. Gottesman's proposal In general achieves these 
objectives, by setting reasonable standards for experiments for which 
sufficient Information exists to do so and by assigning oversight 
responsibilities for certain experiments to the'IBC and the NIH based 
on a rational assessment of potential hazard. 
The portions of the Gottesman proposal for which we suggest 
clarification or revision are listed below with our comments. 
Section I.B. Definition of Recombinant DNA Molecules 
"Synthetic DNA segments likely to yield a potentially 
harmful polynucleotide or polypeptide (e.g. a toxin 
or a pharmacologically active agent ) shall be considered 
as equivalent to their natural DNA counterpart." 
Comment ; We agree that the statement regarding synthetic 
DNA should be Incorporated, however, we suggest rewording 
to clarify that not all pharmacologically active agents 
are harmful. 
"Synthetic DNA segments likely to yield 
pharmacologically active agents or a potentially harmful 
polynucleotide or polypeptide (e.g. a toxin) shall be 
considered as equivalent to their natural DNA counterpart." 
III.B.2. Experiments In Which DNA from CPC Class 2 or Class 3 Agents 
cloned In Nonpathogenlc Prokaryotic or Lower Eukaryotic 
Host Vector Systems. 
Comment : The title of this section should be expanded to 
Include Class 4 and Class 5 agents since these two 
categories are discussed under this section In subpart 
III.B.2.b. 
III.B.5. Experiments Involving More than 10 Liters of Culture 
It Is our belief that the 10 liter limit applied to the 
definition of large scale experiments Is by necessity, 
arbitrary. It would seem however, that a definition 
based on total number of organisms per culture might be 
a more reasonable approach to establishing a limit 
We suggest that the limit be based on the total number 
of organisms In any vess^^ of any size and recommend that 
the limit be set at 1x10 cells. This c^grespondf to 
10 liters of culture at a density of 1x10 cells/ml. 
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