Attachment II - Page 34 
50886 Federal Register / 
and cell fusion will be subject to PMN, it 
requests comment on implementation 
issues. PMN requirements will not be in 
effect for microorganisms produced 
through these techniques until the 
Agency has reviewed public comments 
and addressed implementation issues. 
ii. Certain other techniques of 
biotechnology are also used to transfer 
nucleic acid between microorganisms, 
but the Agency is uncertain whether 
these techniques will permit 
combinations that transcend natural 
boundaries. (EPA acknowledges that 
genetic boundaries in microorganisms 
are difficult to define because 
understanding of gene flow among 
microorganisms is changing.) Therefore, 
the Agency is uncertain whether these 
other techniques should also be 
considered to produce “new” 
microorganisms. Techniques in this 
category are transformation, 
transduction, transfection, and 
techniques that promote conjugation 
and plasmid transfer. The Agency 
requests comment on the 
appropriateness of PMN review for 
microorganisms produced through these 
techniques. 
iii. EPA is uncertain as to whether 
microorganisms produced through 
techniques of undirected mutagenesis, 
such as irradiation or use of chemical 
mutagens, are “new.” On the one hand, 
microorganisms that are very unlikely to 
evolve in nature may be produced 
through these techniques. On the other 
hand, undirected mutagenesis is similar 
to natural processes of mutation and it 
operates within a single gene pool. The 
Agency requests comment on whether 
products of this technique should be 
considered new and subject to PMN. 
iv. EPA has concluded that 
microorganisms found in nature and 
used commercially without deliberate 
genetic intervention are "naturally 
occurring" and therefore are not subject 
to PMN. The Agency also believes that 
artificially selected microorganisms fall 
into the general category of “naturally 
occurring.” 
Microorganisms produced through a 
combination of two or more of the above 
techniques would be subject to PMN if 
any single technique considered to 
produce "new" organisms were 
employed in their development. 
b. "New” versus "naturally occurring" 
substances. In compiling the TSCA 
Inventory and in keeping to current, EPA 
distinguishes between "new” 
substances, which are subject to PMN, 
and “naturally occurring" substances, 
which are not. Under the Inventory 
reporting rules, the Inventory 
automatically includes (but does not 
specifically list) all “unprocessed" 
Vol. 49, No. 252 / Monday, December 
naturally occurring substances and 
naturally occurring substances that are 
processed only by "manual, mechanical, 
or gravitational means; by dissolution in 
water; by flotation; or by heating solely 
to remove water” (40 CFR 710.4(b)). (For 
the purposes of this notice, these 
substances are referred to as "naturally 
occurring".) Because naturally occurring 
substances are included on the 
Inventory as existing substances, they 
are exempt from PMN. On the other 
hand, chemical substances that are 
chemically extracted or reacted from 
naturally occurring substances are not 
naturally occurring. These substances 
had to be reported for the Inventory, 
and, if they are not now listed on the 
Inventory, they are “new." 
This approach reflects a general 
philosophy that human intervention at a 
relatively simple level does not remove 
a substance from the category of 
naturally occurring. The act of 
mechanically isolating a substance from 
nature does not alter its status as 
"naturally occurring" or make it subject 
to PMN. In short, two principles must be 
considered in determining whether a 
substance is exempt from PMN by virtue 
of being naturally occurring. First, it 
must be derived from nature. Second, 
the extent of human intervention in 
producing it must be limited. 
The Agency believes that a similar 
logic should be used to determine 
whether an organism is “new.” in 
principle, naturally occurring organisms 
are those that (1) exist as a result of 
natural events or processes, or (2) have 
been developed as a result of limited 
manipulation of natural processes. For 
example, normal events of reproduction 
or evolution do not produce “new 
chemical substances" subject to PMN, 
any more than chemical reactions in 
nature, unmediated by humans, create 
"new chemical substances.” Similarly, 
human exploitation of natural 
reproductive processes, as in the case of 
traditional animal and plant breeding, 
does not create a “new chemical 
substance," any more than does 
extracting a nonliving substance by 
manual, mechanical, or gravitational 
means from a naturally occurring 
substance. 
The techniques of modem molecular 
biology are revolutionary in that they 
allow humans to override natural 
genetic contraints, creating heretofore 
unknown arrangements of genetic 
material, and to synthesize genetic 
material de novo. New organisms 
produced through these techniques may 
have genomes that do not occur in 
nature, or gene pools substantially 
altered from those that would occur 
31, 1984 / Notices 
through the natural processes of 
reproduction. 
Perhaps the most clearcut examples of 
techniques that can be used to create 
"new" organisms are the techniques of 
R-DNA, R-RNA, and cell fusion which 
allow the combination of genetic 
material from organisms that do not 
exchange genetic material in nature. 
Organisms produced through these 
techniques can be considered "new” in 
the sense that their natural gene pool — 
i.e., the total genetic information 
possessed by a population of organisms 
that naturally exchange genetic 
material — has been altered. 
In theory, PMN requirements could be 
based strictly on this concept of the 
natural gene pool. Under this approach, 
organisms containing genetic material 
from organisms that do not exchange 
genetic material in nature or organisms 
whose gene pools had been otherwise 
altered, would by definition be "new." 
However, in practice, this concept 
would be difficult to apply. Although the 
theoretical concept of the gene pool is 
clear, the actual borders of gene pools 
can be extremely difficult to determine. 
For plants and animals, the natural gene 
pool aprpoximates the taxonomic unit 
“species,” but the taxonomic boundaries 
between species are not always clearly 
established. Many sexually reproducing 
organisms that do not interbreed in 
nature may do so when natural 
reproductive barriers are removed by 
human intervention. It is even more 
difficult to define natural genetic 
exchange boundaries for prokaryotic 
organisms (Ref. 5). Their genetic 
material is exchanged through such 
mechanisms as conjugation, plasmid 
transfer, transduction and 
transformation. While it appears that 
there are boundaries for genetic 
exchange among microorganisms, there 
is no commonly accepted basis for 
describing these limits. 
Given the elusiveness of a generally 
accepted definition of natural genetic 
exchange boundaries, and given the 
importance of human intervention in 
determining “newness," EPA belives 
that the most appropriate way to 
distinguish between “new” and 
"naturally occurring" microorganisms is 
by the methods or processes by which 
they are produced and the level of 
human intervention involved. Thus, 
while a biological definition of "new" 
and "naturally occurring" might in 
theory be preferable, EPA believes that 
such definitions may be unworkable for 
practical reasons. Therefore, the Agency 
proposes to determine whether a 
commerical microorganism is now or 
naturally occurring on the basis of the 
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