is in order because of possible changes in the host range 
and ecology of hybrid pathogens created by extracellular 
recombination. The inclusion of plant pathogens is also 
inconsistent with the exclusion of human pathogens such 
as Vibrio cholerae which are known to exchange plasmids 
containing chromosomal genes with E. coli and which have 
been excluded from the list of exempted species for good 
reason. Additionally, the ecological impact of an increased 
rate of exchange facilitated by recombinant DNA experimentation 
cannot be assessed. 
2. Nor can we agree with the exemption in § I-E-l for 
DNA that has been extracted from host cells. Such DNA is 
novel in that it would often contain sequences and genetic 
functions from widely separated species. As we have already 
noted, initial results of the experiments of Drs. Rowe and 
Martin indicate that polyoma DNA cloned in E. coli retains 
its infectivity in the linear form. It seems clear, therefore, 
that certain cloned DNAs need special handling for safety. 
Experiments using cloned DNA will be conducted in 
laboratories in which bacterial contamination of buffer 
solutions and cultures is a common occurrence and where 
healthier strains related to crippled host strains may be 
commonly used. Consequently, the possibility of genetic 
transformation must be avoided. Transformation and transfection 
of prokaryotic and eukaryotic cells have been reported to 
occur both in vivo and under extreme conditions in the 
[A-189] 
