milligram per day is the upper limit for the amount of high 
molecular weight DNA excreted by a healthy American. (F: 694-698) . 
It would seem prudent to provide protection for the environment 
which is equivalent to that provided by the mammalian small 
intestine.. That is, naked recombinant DNA should be degraded 
and solutions containing it should be decontaminated before 
disposal . 
D. Physical Containment 
1. We endorse the banning of mouth pipetting under PI 
conditions . 
2. S§ II-B-l-a- (9) , II-B-2-a- (12) , and II-B-4-a- (16) 
mandating insect and rodent control programs on recombinant 
DNA labs are too weak. These sections should specify that 
the laboratories where recombinant DNA experiments are conducted 
"shall be free of insects and rodents which are not used as 
experimental animals." This was one of the major public 
concerns that emerged from the debates over recombinant DNA 
research in Cambridge, Massachusetts. Such insects provide 
a possible means of escape for organisms containing recombinant 
DNA molecules . The public deserves to know that important 
and sometimes expensive containment measures will not be 
breached by household pests. 
E. Genetic Transfer : Implications for Physical and 
Biological Containment 
Several findings are relevant to the problem of genetic 
transfer. (See detailed discussion in § IX.) Though it has 
been shown that E. coli K12 does not colonize the gut in the 
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