More than three years ago we called attention to the
possible consequences of the indiscriminate use of recombinant
DNA techniques (Science 185, p. 303, 26 July, 1974). Although
there was no scientific evidence that recombinant DNA experiments
could be hazardous,we conjectured that the construction and
propagation of supposedly novel DNA elements in Escherichia
coli might result in the widespread dissemination of new genetic
combinations. Recognizing a need for wider discussion and addi-
tional information, we recommended that certain experiments be
deferred until the question of potential hazards and how to
deal with them could be better evaluated.

In the ensuing four years the discussions, evaluations
and experiences concerning recombinant DNA research have
strikingly altered our assessment of the risks. More than
250 scientific investigations involving the construction and
propagation of many different recombinant DNA molecules have
been carried out in the United States and abroad with no indica-
tion of harm to humans or the environment. Where their ability
to survive has been examined, organisms modified by recombinant
DNA techniques do not compete successfully with their parental
or wild-type organisms in the absence of a selection for the
recombinant organism. Furthermore, there are increasing indica~_
tions that supposedly novel recombinant DNA molecules can
arise in nature by reactions akin to those used in the labora-
tory.

There is also virtually unanimous agreement by experts in

infectious disease and epidemiology that strain K12, the variant
of E. coli widely used for recombinant DNA experiments, can
neither colonize normal human or animal intestinal tracts, nor

be transformed into infectious or pathogenic organisms by the
addition of a bit of foreign DNA. In view of these reassuring
developments and assessments,we regard our earlier apprehensions
about the risks of recombinant DNA experimentation as being
exaggerated and unwarranted.

During the past three years new insights about the structure
and organization of genes in higher organisms have been obtained
using recombinant DNA methods and these have radically altered
our views on gene function in health and disease. Isolation ¢. synthe sts
of genes coding for insulin, growth hormone and somatostatin
are realities, not predictions. We believe that similar advances
with genes coding for other therapeutically valuable proteins,
for anti-bacterial and anti-viral vaccines, or for industrially
important enzymes are forthcoming; these will accelerate the
realization of practical benefits from DNA research.

In light of the impressive advances of scientific know-
ledge stemming from recombinant DNA research, the development
of procedures to minimize the risks, and the widespread con-
census that the unusual hazards postulated earlier for recom-
binant DNA have been exaggerated, we regard the enactment of
legislation to govern and regulate recombinant DNA experimentation
as undesirable and unnecessary. Legislation on this issue is
not likely to increase significantly the safety of the experi-

mentation; rather, its administration would create a costly
bureaucracy and inhibit basic research on important biological
and medical problems. We are, therefore, persuaded that such
special legislation would be detrimental to the long-term

public welfare.

In our view there already exist effective mechanisms
and sufficient authority in various statutes of the Public
Health Service, Act:to both ensure safe conduct of recombinant
DNA experimentation, and to alleviate the public's remaining

anxieties about this line of research.

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