- 2 - 
4. Exempt experiments that do not require registration but for which V 1 
containment is recommended* 
a) recombinant DNAs not in organisms or viruses 
b) recombinant DNAs derived from non 7 viral sources which are propagated and 
maintained in tissue cultures cells 
c) E. col i K-12 host-vector systems 
d) S_. cerevi siae host-vector systems 
e) asporogenic EL subti 1 i s host-vector systems 
* excepting DNAs from CDC class 3, 4 or 5 organisms 
For copies of the current Guidelines or additional information please contact 
either Dr. Paul V. O'Donnell (X7495) or Mr. Franklin Pearce (X8081). 
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