Tab A - Page 34 
Is zero, the product (the probability of ham) will be zero. If one or more of 
the factors is very Improbable (probability close to zero), the probability of 
ham for the overall process will be extremely small as well. 
The Initial steps in this analysis will be common to all recombinant ONA 
experiments: a) The organism must contain foreign genes, that Is, have some 
unique property as a result of recombinant ONA rearrangements , not present in 
naturally occurring organisms, b) The organism must escape from the experi- 
mental situation, c) The organism must survive after escape, d) The organism 
or the recombinant ONA specifying the hamful product must become established 
in an environment. 
The general applicability of these four steps serve as the basis for the 
specific containment procedures recommended in the Guidelines for organisms 
containing recombinant ONA. Thus, laboratory experiments are designed to 
minimize factor (b) (escape from the experimental situation) by the use of 
appropriate physical containment techniques. The likelihood of steps (c) and 
(d) are reflected in the estimate of the biological containment of a particular 
system. If an organism escapes, but cannot survive or grow sufficiently to 
establish itself, or, alternatively, pass on the recombinant ONA to some other 
organism, it can have no long-tem effect on man or the environment. Organisms 
containing recombinant ONA have a potential to affect the environment only if 
the organisms have the capacity to survive and replicate; If not, the 
probability of harm approaches zero. The concept embodied in (a), that 
organisms are subject to special oversight only if they are In some sense 
unique (contain foreign genes), is reflected In the exemption of many 
recombinant ONA experiments from the requirements of the Guldel Ines. For 
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