Type 1 : Construction of new, autonomously 
replicating bacterial plasmids that might 
result in the introduction of genetic deter- 
minants for antibiotic resistance or bacterial 
toxin formation into bacterial strains that 
do not at present carry such determinants; 
or construction of new bacterial plasmids 
containing combinations of resistance to 
clinically useful antibiotics unless plasmids 
containing such combinations of antibiotic 
resistance determinants already exist in 
nature. 
Type 2 : Linkage of all or segments of the 
DNA's from oncogenic or other animal 
viruses to autonomously replicating DNA 
elements such as bacterial plasmids or 
other viral DNA's. Such recombinant DNA 
molecules might be more easily disseminated 
to bacterial populations in humans and other 
species, and thus possibly increase the 
incidence of cancer or other diseases. 
Second, plans to link fragments of animal DNAs to 
bacterial plasmid DNA or bacteriophage DNA should 
be carefully weighed. . . . 
Third, the Director of the National Institutes of 
Health is requested to give immediate consideration 
to establishing an advisory committee charged with 
(i) overseeing an experimental program to evaluate 
the potential biological and ecological hazards of 
the above types of recombinant DNA molecules; 
(ii) developing procedures which will minimize the 
spread of such molecules within human and other 
populations; and (iii) devising guidelines to be 
followed by investigators working with potentially 
hazardous recombinant DNA molecules. 
Fourth, an international meeting of involved 
scientists from all over the world should be convened 
early in the coming year to review scientific progress 
in this area and to further discuss appropriate ways 
to deal with the potential biohazards of recombinant 
DNA molecules. 
