by transduction to another bacterium. Dr. Hel inski indicated that 
in terms of approximating physiological conditions in a test tube, 
the mild shock treatment employed to facilitate transformation in 
E. coli was not that far from the norm. Similar levels of calciun, 
for example, are found in the intestinal tract. 
Dr. Hel inski was followed by Dr. Jtowe who presented the RAC 
recommendations on viral DNA. Dr. Rowe briefly described the various 
classes of viruses including retroviruses (which carry reverse 
transcriptase), baculoviruses (DNA viruses that infect insects), 
and papova viruses (which include SV-40 and polycma) . Dr. Ftowe 
described the containment levels required for viral DNA. 
A considerable discussion ensued with DAC members asking why 
viral DNA required such high containment levels. Dr. John Tooze 
( EMBO) contrasted the European attitude toward cloning viral DNA. 
He first pointed out that many European countries had adopted 
guidelines but had not felt it necessary to pass laws. In each 
country, each virus cloning proposal is put forth to a national 
committee and is judged individually. He noted that when viral 
DNA such as SV-40 or polyoma is used as a vector it will pick up 
host DNA by natural recombination, so that to clone mouse DNA via 
polyoma in mouse cells at a P3 level does not seen justifiable. 
Dr. Zaitlin concluded the section on Experimental Guidelines by 
discussing changes suggested for plant ENA. Dr. Chilton (University 
of Washington) testifying as an invited witness suggested that the 
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