Page 5 of Attachment E 
prokaryotic backgrounds. It is clear that further studies of the molecular 
genetics, pathogenicity, ecology and other properties of organisms will 
continue to provide information relevant to the assessment of risk and 
that this source is no less important than specifically targeted ex- 
periments. 
Replies to our Questionnaire (sections I and II) indicate that there are 
several projects currently underway directed specifically towards risk 
assessment. These include the two separate polyoma virus experiments 
currently sponsored by EMBO and by NIH and several NIH contracts 
aimed at testing and verification of EK2 and EK3 systems. Preliminary 
results, as well as conclusions from the NIH-EMBO Virology Workshop 
indicate that these studies are unlikely to reveal unknown hazards. 
These and other experiments which are aimed at elucidating various 
aspects of the ecology and natural history of microorganisms should 
provide useful information and will be important in the development of 
host-vector systems other than those based on E. coli K-12. 
In summary, our analyses have revealed no scientific findings to 
justify any of the three concerns listed above; no risk unique to 
recombinant DNA research has been identified. Available evidence 
indicates that recombinations of the type made possible by this new 
technology can occur in Nature. Evaluation of E. coli K-12 shows that 
this bacterium is essentially harmless and that insertions of segments 
of foreign DNA into its genome cannot alter this property. With few 
exceptions, it seems likely that the same will prove true of other host 
bacteria. These conclusions cannot be ignored if the guidelines 
governing recombinant DNA research are to remain rational and useful. 
Part I of the following report contains a detailed summary of information we 
have gathered and a selected bibliography. Part II includes source materials, 
documents received in reply to our questionnaire and the texts of reports which 
may not be readily available. 
[ 384 ] 
