of experiments, particularly those in which a population of naturally 
recombining DNA such as bacteriophage T7DNA or fragments of E. coli 
DNA will be cloned in an E. coli_ host. Dr. Littlefield was followed 
by Dr. Maxine Singer (NIH) who presented additional testimony on the 
definition of recombinant ENA. Dr. Singer noted that neither the 
current nor proposed revised Guidelines provide any guidance on 
containment levels for experiments that involve chemically synthesized 
DNA. Dr. Singer proposed wording for synthetic DNA. 
In the discussion that followed, Dr. Fredrickson again noted 
that the RAC believed the current definition to be too inclusive 
and ignoring the phenomena of natural recombination. The RAC therefore 
introduced the concept of "novel recombinants." The RAC would be 
charged with the responsibility for development of a list of exempt- 
tions. Members of the DAC agreed with the concept of such a list 
but expressed concern over the lack of clarity in the term "normal 
physiological process." 
The invited and public witnesses also commented on the definition 
of recombinant DNA and the distinction between novel and non-novel 
recombinants. Ms. Nancy Pfund (Sierra Club) asked what data had been 
used to justify the revisions made in the Guidelines. She further 
suggested that emphasis be placed on the concept of safety rather 
than novelty in categorizing recombinants and that all publications 
be required to list the levels of biological and physical containment 
iii 
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