14 
in the Recombinant Advisory Committee's proposal, and I would like to point 
these out to you. 
First of all, the term "different genomes" has been deleted. This 
term could well be ambiguous, as has been pointed out by the EMBO Com- 
mittee, and the substantive point is in fact taken care of by the def- 
initions of novel and not-novel that follow further down the page. 
Secondly, the term in the second sentence of the definition, "the 
capacity to infect some host cell and be maintained therein," which ap- 
pears in the proposal from the Committee, is replaced in the Berg wording by 
the phrase, "that can replicate in or be integrated into the genome of a 
living cell." The phrases are, in my judgment, essentially equivalent, but 
the suggested wording is more explicit, and eliminates the confusion sur- 
rounding the word "infect," a word whose meaning is not always clear. 
Now, a second significant change in the wording as proposed by Berg 
occurs in the third sentence of the definition, under little "a." If you'll 
find that, please--Whereas in the original proposal from the Committee, the 
word "novel" refers to recombinant DNA molecules containing natural DNA seg- 
ments or reverse transcripts not known to exchange chromosomal DNA by normal 
physiological processes, the adjective "chromosomal" has been omitted from 
in front of the word "DNA" in the proposal that Dr. Berg has made. This 
change is again consistent with the comments made by the EMBO Committee and 
by Stanley Cohen in Document 18 in the Orange Book. The adjective appears 
unnecessary to these commentators, since plasmids are known to pick up chro- 
mosomal DNA fragments, and any two species which can exchange plasmids in 
nature are then very likely also to exchange chromosomal DNA by the plasmid 
route. Thus, the exchange of plasmids alone is indicative of exchange of 
chromosomal DNA. The growing appreciation of the ubiquity of insertion 
sequences as a mechanism for recombination supports this view. 
Finally, Dr. Berg has proposed a classification scheme for experi- 
ments with the synthetic DNAs to be inserted in Section III, subsection B5. 
I could describe these now, Don, but you may wish to wait until you come to 
that section. 
DR. FREDRICKSON: I think I would like you to defer that, Maxine. 
That is a very special matter, and one that doubtless the RAC would have 
to consider at great length before it would likely become a part of the 
revision . 
DR. SINGER: Right. 
DR. FREDRICKSON: Let me then summarize. You have heard very briefly 
— and just to bring you up to speed should you not be already ahead of 
me — the Committee in its considerations over the year, examining the old 
definitions, found them to be too all-inclusive. They ignored certain 
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