10 
Dr. Thcmashow asked whether the working group could argue that certain organisms 
ought to be exempt on the basis of sequence homology. Dr. Gottesman replied 
that an argument based on a high degree of horology, e.g. , 90% horology in a 
randomly selected gene and not a highly conserved gene, would be acceptable. 
Dr. Dean thought a high degree of horology would argue that no new organism 
would be created by use of recombinant ENA techniques since any change would 
be within the evolutionary range of the bacteria. 
Dr. Baltz asked whether organisms could be added to Appendix A if exchange 
could be shown between organisms by the mechanism of phage transduction. 
Dr. Gottesman replied such an argument would have to be supported by knowledge 
about the transduction mechanism. It does not matter what the mechanism of 
exchange of chromosomal material is as long as exchange can be shewn to occur. 
Dr. Baltz said chrcxnoscmal gene transfer by plasmids has been shewn in Strepto - 
myces but not yet in Streptococcus or Staphylococcus . Since Streptcmyces are 
gram-positive bacteria can these observations be extrapolated to Streptococcus 
and Staphylococcus ? 
Dr. Gottesman said it would be difficult to extrapolate from the Streptcmyces 
to the Streptococcus and Staphylococcus if the plasmids and the mechanisms are 
different in the Streptcmyces ? arguments advanced in support of a recommendation 
should be supported scientifically. 
Dr. Friedman asked whether the pathogenicity of certain Streptococcus and 
Staphylococcus will affect RAC's deliberations. 
Dr. Gottesman said the fact these organisms are pathogens will reflect on any 
reccrrme nda t ion since the question is whether a better pathogen can be constructed 
by recombinant ENA methods than would occur in nature. Another issue is whether 
records of a pathogen's construction and use should be kept. She reminded 
the group that most experiments involving gram-positive bacteria can currently 
be performed at BL1 containment with IBC registration or notification. 
Dr. Clewell asked hew RAC views sublists of Appendix A which include human 
pathogens. Dr. Gottesman said the organisms included in sublists of Appendix 
A are exempt from the NIH Guidelines because they exchange genetic information. 
Organisms exempted because they are considered to be safe hosts cure listed in 
Appendix C. 
Dr. Gottesman said RAC's job is easier if working group recommendations are 
very clearly drawn. She reccnmended a proposal be written so that even 
if RAC does not accept the whole recommendation, it could accept some part 
of the reccrrrrendation . The working group should not attempt to squeeze the 
science to fit the recommendation but should craft the recommendation to fit 
the science. She suggested the working group outline the strongest scientific 
arguments supporting their recommendation ( s ) . 
[541] 
