-7- 
bacteria, use the wide-host range P plasmids as conjugative vehicles in a 
variety of bacteria. These plasmids transfer to almost any Gram negative 
species with bacterial chromosomes and other plasmid replicons. Deri vatives C P 1 ) 
of these plasmids carrying segments of chromosomal material from such diverse 
organisms as E_. col i and P_. aeruginosa have been obtained. Recently, P- 
plasmid-Mu phage cointegrates have been used to induce the transposition of 
bacterial chromosomal segments onto the plasmid. Apparently this method 
works in species other than E^ col i as well. Secondary transfers of such P 1 
elements could be judged as even more biohazardous than, for example, "run- 
away" Col El- or PSC1 01 -recombinant plasmids, the vectors of which have a 
much more restricted host range than the P plasmids. Furthermore, co- trans- 
mission of non-cl ustered genes is much more likely to occur by conjugation, 
which allows for the transfer of extended regions of "donor" DNA, than by 
individual in vitro recombinant plasmids, each of which is likely to carry 
only a short segment of "donor" DNA, and more than one of which would not 
normally be co-acquired by or co-maintained in the same host cell because 
of incompatibility. The proposal which I have put forward will likely bring 
more genetic experiments under the regulatory umbrella and presumably increase 
the overall biosafety in bacterial genetic work. 
4) The status of experiments involving "non-novel" recombinant molecules and 
HV systems of organisms under blanket prohibitions . The status of pro- 
hibition (i) relating to experiments involving the cloning of DNA derived 
from the pathogenic organisms in CDC classes 3, 4, and 5, moderate risk on- 
cogenic viruses or cells infected with such agents, should be clarified. Under 
the Guidelines , such experiments are prohibited regardless of the host-vector 
system used. But since the Guidelines will not apply to experiments not 
involving "novel" molecules the cloning of such DNAs in the host or origin 
[Appendix A — 116] 
