38 
May I have the next slide (2), please? 
Slide 2 
Experiments Not to be Initiated at Present 
1. Experiments involving DNA from classes 3, 4, and 5 (CDC) 
2. Deliberate formation of recombinants wtien genes for dangerous 
toxins are present 
3. Deliberate formation of recombinants from plant pathogens if likely 
to increase virulence or host range. 
4. Widespread release into environment of any organism containing 
recombinant DNA, except when no reasonable doubt of safety. 
5. Transfer of drug resistance traits to new microorganisms, if 
transfer could compromise drug use in medicine or agriculture 
6. Large scale experiments if harmful products made. Exceptions 
possible with permission of Advisory Committee. 
First, any experiments in which a portion of the recombinant DNA de- 
rives from pathogenic organisms listed under classes 3, 4, and 5 of a docu- 
ment entitled "Classification of Etiologic Agents on the Basis of Hazard," 
that is published by the Center for Disease Control — that is, the CDC, 
United States Public Health Service. This document categorizes naturally 
occurring organisms and viruses known to be pathogenic to man, and to agri- 
culturally important species on a scale of increasing hazard going from 1 to 
5. Class 5 agents are excluded from the United States by law. Class 4 in- 
cludes such agents as wild-type smallpox virus, and wild-type yellow fever 
viruses. Class 3 includes such agents as arboviruses, which are responsible 
for encephalitis, psittacosis agents, rickettsial agents. Class 2 includes 
agents which may produce diseases of varying degrees of severity if acciden- 
tally inoculated into laboratory workers, but which are considered normally 
containable by standard laboratory practice. These include bacteria such as 
species of Salmonella , agents which cause amoebic dysentery, viruses for 
mumps, measles and rubella. Class 2 agents may be used in recombinant DNA 
experiments. 
The second group of experiments involves the deliberate formation of 
recombinants containing the genes for toxins of very high toxicity. Ex- 
amples of this group of toxins are the botulinus toxin or diphtheria toxin. 
Third, deliberate formation of recombinant DNA using the DNA from plant 
pathogens if the resulting material might increase either the virulence of 
the pathogenic material or the range of species susceptible to the disease. 
[179] 
