47 
are able to focus our attention on the more critical issues where it prop- 
erly belongs. 
However, there is some vagueness. There are two apparently alternative 
criteria which are stated for judging whether a recombinant DNA molecue is 
novel or not. Does it have to be non-novel by both of these criteria, or 
would only one criterion suffice? I find that this point bothers me im- 
mensely because it touches on my own research. It turns out that we are 
doing recombinant DNA experiments with Ti plasmids, tumor-inducing plasmids 
which cause plant tumors. It turns out that the Ti plasmid can be coaxed to 
grow in E. col i rather unwillingly and briefly. Thus, by one of the two 
stated criteria, Ti plasmid cloning experiments would be eligible for the 
excluded list. All right, if they don't make the list, the alternative if 
you proceed through the Guidelines and see where such experiments fall out, 
they would be judged to have to go under P3+EK2 containment. So you see, my 
life hangs by a thread here. I don't know whether these experiments will or 
will not be eligible to fall on the excluded list. I find that this amount of 
vagueness in what the criterion is is too much vagueness, and we ought to 
rectify that by making some statement as to whether one or both criteria have 
to be met by a given system in order to be eligible for the list. 
My second point is that it is not stated whether things will more or 
less automatically go on to the list of excluded experiments or whether 
additional criteria will be applied by the Director and his committee before 
judging that they belong on this list. If Lhere are going to be additional 
criteria applied, I feel that they ought to be stated in this introduction. 
For example, will the pathogenicity of the organism being used as a host be 
of concern in deciding whether things should go on the list? Would the 
conjugative promiscuity of the plasmid that is going to be used as a vector 
be considered? As an example, would RP4 , which is a highly promiscuous 
conjugative plasmid be listed as a safe cloning vehicle for any of the wide 
range of bacteria to which it can be transmitted by conjugation? It seems a 
not very sensible way to go about an experiment, but by the letter of the 
stated criteria it would certainly be eligible to go on the list. 
In my opinion some of the recombinant DNA experiments which would 
fulfill the criteria for exclusion as stated explicitly here, should never- 
theless remain under the Guidelines. As a specific example, the cloning 
of the Agrobacterium Ti plasmids, which we are working on in E. coli, should, 
despite the definition, be considered novel recombinant DNA for the present 
until the properties of such recombinant DNA have been assessed more care- 
fully. 
I would like to see considerable clarification for the benefit of 
scientists as well as the public, of what range of experiments we can now 
expect to find listed as outside the Guidelines. I support strongly the 
idea of excluding many experiments which are generally regarded as safe; 
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