RAC to make clear whether or not the source of a transposon 
should be considered. In this case the donor plasmid was 
generated by recombinant DNA technology but the microbial 
derivative or transconjugant did not contain any DNA sequences 
other than those of the unmodified transposon as evidenced by 
genetic means and DNA hybridization. The data were examined by 
two independent groups including a committee of the NIH. 
Dr. Vidaver asked the committee to consider alternative one of 
tab 1316, that is: 
"Unmodified transposons (wild-type) that become 
inserted into the chromosome, even if carried by a 
recombinant plasmid, are not subject to these 
guidelines. For example, it is common to use vectors 
that either are naturally unstable (suicide vector) in 
a desired host or that can be rendered unstable by 
manipulating physiological conditions. In the process 
of suicide (inability of the vector to replicate), 
transposon transfer may occur, this process is not 
considered recombinant DNA." 
Dr. Vidaver said this could be an addendum to Section I-V, or 
inserted as a footnote as it is simply a clarification of what 
does and does not constitute recombinant DNA. 
Dr. McGarrity said final action could not be taken on this issue 
because it had not been published in the Federal Register for 
public comment. However, it was on the agenda in an attempt to 
gain some sense of the committee for future action. 
Dr. Roberts said he agreed that the alternative presented by Dr. 
Vidaver was completely clear as to what a transposon does and 
that it does not constitute recombinant DNA as considered by the 
RAC. Dr. Pagano agreed. Dr. Erickson said he was not quite so 
sanguine about it. He said looking at it from the mammalian 
point of view and looking at retroviruses and retrotransposons 
there were manipulations that could be imagined in a non-modified 
retrotransposon such as injection into an early embryo causing 
integrations that would not naturally occur and could potentially 
be harmful. He said he had no other alternative to propose but 
he did not feel completely satisfied with this alternative. 
Dr. Gellert asked what impact this would have on experiments 
involving inserting a transposon carrying a drug-resistance 
element into a bacterial species where that drug resistance is 
not normally found. Dr. Gellert asked if this were done, not by 
mating, but by construction of a plasmid in vitro , which carries 
the transposon into a strain where the plasmid will disappear but 
the transposon will insert, would this be an approved experiment 
or not. Dr. Vidaver replied it had been done and that antibiotic 
Recombinant DNA Research, Volume 13 
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