Recombinant DNA techniques
In parallel to the use of pathogenic micro-organisms in the laboratory, 1970 marks the emergence of a new discipline: molecular biology. This discipline arose following a series of remarkable discoveries in fundamental research, starting just before the middle of the last century when Avery established that deoxyribonucleic acid (DNA) is the universal support of hereditary properties and contains the genetic information of living beings. This discovery was followed by the publication in 1953 of the work of Crick, Watson, Wilkins and Franklin identifying the double helix molecular structure of DNA (Watson and Crick, 1953; Wilkins, Stokes and Wilson, 1953; Franklin and Gosling, 1953), then in 1965 by the first description of restriction enzymes (by Linn and Arber), proteins capable of cutting DNA at specific sites.
This was the starting point for laboratory applications of molecular biology. The techniques (also referred to by the term "genetic engineering") allowing the insertion of a fragment of DNA (containing one or more genes) into another DNA will progressively refine with the aim of precisely and efficiently modifying the genome and the hereditary characteristics of living organisms. The aim of researchers was sometimes fundamental (better understanding of the functioning of the genome) but numerous teams of scientists also aimed to generate organisms with new properties through the manipulation of DNA. This is how the first genetically modified organisms (GMOs) were developed, and the so-called "modern biotechnologies" came into being.
The awareness of the potential risks associated with the use (still in its infancy) of these molecular biology techniques, and the products derived from them, arose rather rapidly. The very first debates on genetic engineering took shape towards the end of the 1960s within the scientific community, particularly in North America. The question was raised whether the combination of DNA sequences from different species, even unrelated (commonly known as "recombinant DNA"), could not result in new types of pathogenic organisms. This questioning culminated in 1972 with the work of the team of Paul Berg (Jackson et al., 1972). The American biochemist, one of the pioneers of recombinant DNA, successfully carried out the cloning of a fragment of the oncogenic SV40 virus in a bacterial plasmid. However, his work led him, as well as some of his colleagues, to question the risks with which researchers handling this type of DNA were being confronted (they were particularly concerned about possible health consequences of the deliberate or accidental transfer of SV40 tumoral genes into Escherichia coli, a bacteria commonly used in the laboratory but also naturally present in the human digestive system). These fears were increased by the use of these techniques by a growing number of researchers and by the fact that the scientists working at that time on recombinant DNA were largely biochemists, less respectful of or less accustomed to the application of safety measures than microbiologists.
On Berg's initiative, North American scientists met in 1973, first at Asilomar, then during the "Gordon Conference on Nucleic Acids" (see text box). The scientific community committed itself to considering the potential risks linked to recombinant DNA techniques. Already at that time, the implementation of specific containment and personal protective measures was being considered. They were primarily aimed at guaranteeinging the safety of those exposed, essentially the scientists themselves, and to avoid any release into the environment. They were the first steps towards the concepts of "biosafety" and the assessment of risks associated with activities involving recombinant DNA in the laboratory.
However, the major outcome of these first conferences was the appeal, launched by Berg and some other scientists (including Watson), to the scientific community to impose a voluntary moratorium on experiments involving recombinant DNA until the holding of an international conference aimed at assessing the potential risks of this type of research (Berg et al., 1974). Despite the protests of certain scientists (who wished to continue this type of experiment without restrictions), this appeal was upheld, at first only by North American researchers but later also by some European and Japanese researchers.
The second Asilomar conference ("Asilomar Conference on Recombinant DNA Molecules"), organised by Berg, was held in February 1975. It brought together 150 scientists, but also some legal experts and journalists. The participants decided (non-unanimously) to lift the moratorium imposed one year earlier. They particularly concluded to the necessity of managing research work involving recombinant DNA with strict guidelines (Berg et al., 1975).
The Gordon Conference and the two Asilomar conferences: key events for an initial collective awareness of hazards that could be associated with the use of recombinant DNA for researchers, the population and the environment
January 1973 – 1st Asilomar Conference: Discussions on the potential hazard resulting from the use of viruses in genetic engineering.
Scientists established a classification of experiments involving recombinant DNA in order of increasing risk to human health and the environment. Four risk levels were identified: minimal, low, moderate and high risk. A series of increasingly drastic measures corresponded to these risk levels, designed to limit as far as possible the release of recombinant DNA organisms into the environment. Good laboratory practices as well as the training of workers comprised the basic measures for any handling of recombinant DNA. The necessary physical containment measures were also described.
For any experiment, regardless of the level of risk, it was recommended to use biological containment barriers by choosing for example host cells and vectors that could not survive in normal environmental conditions. Certain experiments were simply forbidden: cloning of DNA derived from highly pathogenic micro-organism or coding for toxins, large-scale experiments using recombinant DNA coding for products potentially harmful to humans, animals or plants.
In 1976, in reaction to the debates relating to recombinant DNA, Vittorio Sgaramella, head of the WHO microbiology safety measures programme, launched an appeal to the scientific community for this topic to be the subject of global action (Sgaramella Vittorio, World Health Organisation, letter addressed to Maxine Singer of the NIH, 27/12/1976). The underlying idea was to use safety measures successfully developed in microbiology for the containment of pathogenic organisms for recombinant DNA. A request to this effect was made by the WHO to the National Institutes of Health (NIH) in the United States.
In response to this request and particularly to the recommendations from the second Asilomar conference, the NIH published in June 1976 the first guidelines specifically aimed at research activities involving recombinant DNA and the handling of GMMs in the laboratory. These recommendations were revised in 1979 (with a relaxing of the safety conditions) following experience gained in the field and a better understanding of the actual risks. The NIH guidelines represented the base for the majority of the regulations regarding safety of the use of GMOs in the laboratory, that were subsequently developed.