The Proposed Revised Guidelines exempt from compliance 
non-novel exchangers (P. 33070) . The rationale behind this 
exemption is that such exchanges take place in an unregulated 
manner in nature. There are two objections to this exempt 
category. First, given that one member of a genus is known to 
exchange genetic material with an unrelated species in nature, 
we should not extrapolate that all members of that genus should 
be exempt. We must ask whether other members of the genus would 
meet this organism in a natural setting. Also the extent of 
interspecies exchange within a genus should not be assumed 
without experimental basis. As such, the exemption list is too 
broad. 
Second, the rationale for these exemptions ignores 
basic ecological considerations such as natural rates of exchange, 
simultaneous occupation of ecological niches and the effects of 
concentrated products of such non- novel exchanges in the 
environment. If one piece of DNA is exchanged naturally, that 
does not mean that the transfer of any segment of DNA from that 
organism is safe. Similarly if the organisms exchange DNA in a 
limited manner, increasing the rate of exchange could result in 
the concentration of an enzyme or hormone within an organism 
with unknown results. In the laboratory we do not reproduce 
natural conditions. We place organisms together that might only 
rarely find themselves in close proximity in nature. We must not 
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