103 
(1) Monitoring for release of organisms containing 
recombined DNX ~~ ~~ 
Control of the spread of any agent outside an experimental situation 
to laboratory workers or the outside environment is greatly assisted 
by adequate means for monitoring the agent in question. An example 
is the monitoring for spillage and spread of radioisotopes. The presence 
of radioisotopes is readily measured, and the exposure of laboratory 
personnel or the environment to radiation can be quantified. In the 
case of organisms containing recombined DNA, the situation is fun- 
damentally different. No simple general procedure exists for identifying 
an organism released from the laboratory against the large background 
level of related and unrelated organisms occurring naturally. 
It is possible, however, to devise special pertinent procedures 
for detection of some of the agents used in recombinant DNA exper- 
iments (21). For example, development of bacterial strains, phages, 
or plasmids carrying readily detectable genetic traits would enable 
the monitoring of laboratory personnel, people working in the area, 
and their families for the presence of those agents. This would be 
analogous to the examination of drinking water, lakes, etc. , for fecal 
contamination with enteric organisms. Detection in such instances could 
-7 
be at levels as low as 10 (1 part in 10, 000, 000). The adequacy of 
such screening is not presently known. 
Given a series of events that might characterize a hazardous 
situation, the time factors involved become relevant. Certain types 
of organisms containing recombinant DNA, if they escaped and were 
hazardous, might immediately be perceived as such--e.g., through 
their production of toxic foreign proteins. We might therefore be aware 
of the potential problem soon after dispersal of the organism, and 
reasonable means for minimizing further dispersal could be undertaken. 
In other hypothetical events --e. g. , the escape of a cancer-producing 
DNA fragment- -evidence of harmful effects might not be apparent for 
many years. Moreover, the connection between the causative organisms 
and the observed harmful effects could be difficult to establish. 
(2) Natural occurrence of DNA recombination between 
unrelated organisms" 
