- 2 - 
Another major concern is the inherent inadequacy of data for 
risk assessments upon which containment levels for certain 
experiments are selected. The statement that "certain 
experiments judged to have the potential for extreme hazard, 
should they prove dangerous, are prohibited." It would seem 
appropriate to specify that while seeking the. proof of danger, 
any such experiment would have to be conducted under the most 
conservative level of containment, until such level is proved 
to be unnecessary. 
Additional specific comments • follow: 
Section IV-C-l-a, beginning on page 18, is introduced as a 
speculative discussion, but some points would seem worthy 
of support with additional explanation or reference. For 
example: 
On page 19, paragraph one, line one, it is stated that 
"There are various indications that bacteria and viruses 
containing inserted foreign DNA are less likely to survive 
and multiply than are the original organisms." Examples 
of those various indications would be useful to justify an 
a priori, assumption that recombinant material will necessarily 
be- less robust or hardy than natural materials. 
Also the example given at the bottom of page 19 assumes an 
almost ideal situation of simple negative log growth. Would 
this be expected to occur in a natural system? The dilution 
to a density of one to one million in 207 generations make> 
as^sumptions about the static quality and quantity of the 
substrate available to the organism and it should be 
emphasized that the opposite could be true, i.e., a positive 
log growth phase might ensue under the same conditions. 
Page 24, paragraph one, line five, the statement occurs 
that "In general, one v;ould expect the inserted DMA to 
result in a reduced growth rate and a selective disadvantage 
to the organism, as discussed in 'a' above. Similar 
issues arise where animal viruses serve as carriers of foreign 
DNA." It would be helpful to know the reasons for these 
expectations . 
Page 26, last paragraph mentions "the v;ell documented instances 
in which DNA has become recombined in nature." This might 
be expanded in more detail because it represents an extremely 
important feature of recombinant DNA research. Levels of 
concern about the potential harmful effects on the environment 
seem related to the degree that organisms acquire selective 
advantage different from that acquired in naturally occurring 
events . 
Appendix K — 162 
