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The existing state of ignorance is largely attributable to our 
previous inability to isolate discrete segments of the DNA in a form 
that permits detailed molecular analysis. Recombinant DNA metho- 
dology removes this barrier. Furthermore, ancillary techniques have 
been developed whereby pure DNA segments that contain particular 
sequences of interest can be identified and selected. Of particular 
interest is the isolation of pure DNA segments that contain the genes 
for the variable and constant portions of the immunoglobin proteins, 
the substances providing the major resistance of the body to infections 
or transplants. The analyses of such segments obtained from both germ- 
line and somatic cells should be valuable in determining the mechanism 
of immunologic diversity. 
A major problem in understanding the mechanism by which certain 
viruses cause cancer in animals is how and where the infecting or 
endogenous viral genomes are integrated into the cell's chromosome 
(13). This bears on the question of how the expression of the integrated 
viral genes affects cellular regulation, thus leading to the abnormal 
growth characteristics of cancer cells. With the recombinant DNA 
techniques for isolation and purification of specific genes, this research 
problem is reduced to manageable proportions. It is possible to isolate 
the desired DNA segment in pure form. Large quantities can be obtained 
for detailed study by simply extracting a culture of the bacteria carrying 
the viral DNA segment in a plasmid. 
Since the draft EIS was published in September 1976, substantial 
progress has been made toward realizing the promise of recombinant 
DNA techniques in the area of basic biological research. The following 
is an account of what might be done and what has been done (adapted 
from reference 2 3). 
Much of what is known about the molecular details of gene structure 
and function has been gathered in studies with simple organisms, 
principally E. coU and several viruses that infect that bacterium. 
These studies utilized classical genetic techniques rather than recom- 
binant DNA methods. E_. coli is preferred because the organisms 
are readily grown under controllable laboratory conditions and reproduce 
rapidly. More importantly, perhaps, their relatively small chromosomes 
can easily be manipulated by genetic means, and this makes it possible 
to map the location and arrangement of genes on those chromosomes. 
This achievement was crucial for understanding how the genes of these 
organisms are expressed and regulated. 
