- 2 - 
Second of all, the use of the term "non-conjugative" is inappro- 
priate because the actinomycetes do not exchange genetic information by 
the process of conjugation as it is known for eubacteria. Rather 
actinomycetes exchange genetic information by heterokaryosis . In some 
experiments, the frequency of genetic exchange can be altered by the 
presence of plasmids and some plasmids can mediate their own transfer 
to new hosts. 
I feel that to restrict cloning in the actinomycetes to using 
"non-conjugative" or non-self-transmissible vectors would be unduly 
harsh and would severely restrict research with this valuable group of 
organisms. Considering the level of potential hazard (which I con- 
sider minimal) and the potential benefit (which I view as considerable), 
P2 containment is more than sufficient protection regardless of the 
vectors employed. 
Sincerely, 
Associate Senior Investigator 
DPT: jib 
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