SUMMARY 
The Working Group has been charged with the task of gathering in- 
formation related to assessment of risks associated with recombinant 
DNA research. The information in this report was obtained by ob- 
servation and participation at a number of meetings and hearings, by 
survey of the literature and by direct inquiry to national and international 
organizations, and individual scientists. 
Our analyses indicate that the concerns regarding recombinant DNA 
research can be summarized as follows: 
1. Organisms carrying recombinant DNA may spread in the 
natural environment and disrupt existing ecological 
equilibria. 
2. These organisms might produce some toxic or noxious 
substance, or otherwise cause disease. 
3. By exploiting this technology, scientists may be crossing 
some hypothetical barrier to DNA exchange between 
eukaryotes and prokaryotes and thus affect pathogenicity or 
dispersion of pathological agents. 
Reports from the Falmouth Meeting (section IV) and COGENE- 
sponsored analyses of E. coli K-12 systems (section VI) show that many 
relevant experiments have already been conducted by scientists in such 
closely related fields as epidemiology and infectious diseases. Their 
observations that E. coli K-12 has a limited prospect of survival and their 
consensus that this bacterium cannot be converted into an epidemic 
pathogen by laboratory manipulations with DNA inserts, do much to 
satisfy the first concern mentioned above. In addition (section VII), long- 
term monitoring of laboratory workers who routinely handled K-12 
organisms carrying transmission-proficient plasmids showed no bowel 
colonization despite the fact that the work was carried out without any 
special precautions. If the organisms which carry recombinant DNA 
cannot spread in the natural environment, then clearly the other con- 
cerns are also diminished. The conclusion of a NIH/EMBO Virology 
Workshop (section V) was that recombinant organisms carrying viral 
inserts cannot be any more hazardous than the viruses themselves, and 
in some instances may provide an opportunity to work more safely with 
virulent agents. 
As wilt be seen in the report, important information on the nature and 
possible consequences of the manipulations used in recombinant DNA 
technology comes from experiments in a variety of fields. For example, 
attempts to understand the biological role of restriction enzymes have 
revealed that prokaryotic and eukaryotic DNAs can recombine in vivo. 
Other studies, including those with Agrobacterium tumefaciens and 
plant cells, also show that in some cases there is no natural barrier to 
exchange and expression of genes across the hypothetical prokaryotic- 
eukaryotic barrier. On the other hand, studies of animal virus genomes 
and eukaryotic genes for differentiated functions have revealed 
previously unsuspected possible barriers to their expression in 
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