48 
First we consider shotgun experiments where the foreign DNA is a mix- 
ture of fragments derived from eukaryotes. The recommended physical and 
biological containment is listed for various possible DNA sources, and both 
must, of course, be used. They complement each other. For example, DNA 
from primates requires the most stringent containment, since the estimated 
potential hazard, either from genes that might function in humans with un- 
toward effects or from pathogenic viral DNAs residing in primate tissue, is 
judged to be the most serious. 
The experiments require either P3 and EK3 or P4 and EK2, and it should 
be recalled that only the latter combination, P4 and EK2, is feasible at 
present, and even then, only at a limited number of P4 facilities. That is 
assuming the near-certification of EK2 host-vector systems. 
Another point of interest is that in two instances, primates and cold- 
blooded vertebrates, containment requirements are lower if the DNA is iso- 
lated from embryonic tissue or germ line material, since such material is 
less likely to be contaminated by pathogenic viruses or other adventitious 
agents than is adult tissue. 
Thus, if the foreign DNA is from cold-blooded vertebrates, P2 and EK2 
are required; P2 and EKl can be used if the DNA is from embryonic or germ 
line tissue. In some instances — lower eukaryotes, for example — the guide- 
lines require more or less stringent conditions, depending upon whether or 
not the source of foreign DNA is known to be pathogenic or might be infected 
with a pathogen or is known to make a harmful product. The lower eukaryotes 
include invertebrates, certain plants, yeast, and fungi. 
The next slide (10) summarized the proposed guidelines for shotgun 
experiments when the source of the DNA is a prokaryotic organism. Two 
groups considered: first those prokaryotes which are known to exchange 
genetic information in nature with E^. coli , and the containment recommen- 
dations are low for this group and vary with the pathogenicity of the source 
of foreign DNA. When the source of foreign DNA is a prokaryote that does 
not normally exchange genetic material with I£. coli , the containment recom- 
mendations are higher. 
Finally, the containment requirements are raised in situations which 
are termed on the slide as involving a drug problem — that is, situations 
where experiments may extend the range of resistance of the host cell to 
therapeutically useful antibiotics or disinfectants. 
We now consider the situation where the foreign DNA is still derived 
from chromosomal DNA, but it is purified prior to joining to the vector. 
May I have the next slide, please (11)? 
[189] 
