Excerpted from "Recombinant DNA: Fact and Fiction," Cohen, Stanley 
N., Science Vol. 195, pp. 654-657, 18 February 1977. Copyright © 
1977 by the American Association for the Advancement of Science. 
For all but a very few experiments, the 
risks of recombinant DNA research are 
speculative. Are the benefits equally 
speculative or is there some factual basis 
for expecting that benefits will occur 
from this technique? I believe that the 
anticipation of benefits has a substantial 
basis in fact, and that the benefits fall 
into two principal categories; (i) advance- 
ment of fundamental scientific and medi- 
cal knowledge, and (ii) possible practical 
applications. 
In the short space of 3'/i years, the use 
of the recombinant DNA technology has 
already been of major importance in the 
advancement of fur.damental knowl- 
edge. We need to understand the struc- 
ture and function of genes, and this meth- 
odology provides a way to isolate large 
quantities of specific segments of DNA 
in pure form. For example, recombinant 
DNA methodology has provided us with 
much information about the structure of 
plasmids that cause antibiotic resistance 
in bacteria, and has given us insights into 
how these elements propagate them- 
selves. how they evolve, and how their 
genes are regulated. In the past, our 
inability to isolate specific genetic re- 
gions of the chromosomes of higher orga- 
nisms has limited our understanding of 
the genes of complex cells. Now use of 
recombinant DNA techniques has pro- 
vided knowledge about how genes are 
organized into chromosomes and how 
gene expression is controlled. With such 
knowledge we can begin to learn how 
defects in the structure of such genes 
alter their function. 
On a more practical level, recombi- 
nant DNA techniques potentially permit 
the construction of bacterial strains that 
can produce biologically important sub- 
stances such as antibodies and hor- 
mones. Although the full expression of 
higher organism DNA that is necessary 
to accomplish such production has not 
yet been achieved in bacteria, the steps 
that need to be taken to reach this goal 
are defined, and we can reasonably ex- 
pect that the introduction of appropriate 
'•start" and “stop" control signals into 
recombinant DNA molecules will enable 
the expression of animal cell genes. On 
an even shorter time scale, we can ex- 
pect recombinant DNA techniques to 
revolutionize the production of antibiot- 
ics, vitamins, and medically and indus- 
trially useful chemicals by eliminating 
the need to grow and process the often 
exotic bacterial and fungal strains cur- 
rently used as sources for such agents. 
We can anticipate the construction of 
modified antimicrobial agents that are 
not destroyed by the antibiotic in- 
activating enzymes responsible for drug 
resistance in bacteria. 
In the area of vaccine production, we 
can anticipate the construction of specif- 
ic bacterial strains able to produce de- 
sired antigenic products, eliminating the 
present need for immunization with 
killed or attenuated specimens of dis- 
ease-causing viruses. 
One practical application of recom- 
binant DNA technology in the area of 
vaccine production is already close to 
being realized. An E. coli plasmid coding 
for an enteric toxin fatal to livestock 
has been taken apart, and the toxin 
gene has been separated from the re- 
mainder of the plasmid. The next step 
is to cut away a small segment of the 
toxin-producing gene so that the sub- 
stance produced by the resulting gene in 
E. coli will not have toxic properties but 
will be immunologically active in stimu- 
lating antibody production. 
Other benefits from recombinant DNA 
research in the areas of food and energy 
production are more speculative. How- 
ever. even in these areas there is a scien- 
tific basis for expecting that the benefits 
will someday be realized. The limited 
availability of fertilizers and the potential 
hazards associated with excessive use of 
nitrogen fertilizers now limits the yields 
of grain and other crops, but agricultural 
experts suggest that transplantation of 
the nitrogenase system from the chromo- 
somes of certain bacteria into plants or 
into other bacteria that live symbiotically 
with food crop plants may eliminate the 
need for fertilizers. For many years, sci- 
entists have modified the heredity of 
plants by comparatively primitive tech- 
niques. Now there is a means of doing 
this with greater precision than has been 
possible previously. 
Certain algae are known to produce 
hydrogen from water, using sunlight as 
energy. This process potentially can 
yield a virtually limitless source of pollu- 
tion-free energy if technical and biochem- 
ical problems indigenous to the known 
hydrogen-producing organisms can be 
solved. Recombinant DNA techniques 
offer a possible means of solution to 
these problems. 
It is ironic that some of the most vocal 
opposition to recombinant DNA re 
search has come from those most con- 
cerned about the environment. The abili- 
ty to manipulate microbial genes offers 
the promise of more effective utilization 
of renewable resources for mankind s 
food and energy needs; the status quo 
offers the prospect of progressive and 
continuing devastation of the environ- 
ment. Yet, some environmentalists have 
been misled into taking what I believe to 
be an antienvironmental position on the 
issue of recombinant DNA. 
