Sensational books and films have given some the impression that genetic engineering will result in strange, hideous beasts roaming our cities and countryside while new, incurable diseases decimate the human race. More optimistically, it is sometimes suggested that this expanding technology will lead to the cure for most, if not all, human disease and eliminate hunger from the world by the use of the new crops and livestock which will be developed.
Since humans are ingenious and unpredictable animals, both scenarios are possible but if either happens it will be in the distant future. A recent booklet, The Release of Genetically-Engineered Organisms, gives a more realistic picture of the present status of genetic engineering and its possible effects on our environment.
In one sense genetic engineering is not new. Since man began to live in settled communities, cultivated plants and domesticated animals have been selectively bred to produce unnatural strains and varieties. Without these new genetic combinations the Earth could not support a fraction of its present human population. What is new is a number of “artificial” techniques including recombinant DNA technology and artificial cell fusion or hybridisation.
The new organisms produced by these techniques may not be unlike those obtained by traditional breeding methods and need cause little concern. However, it is also possible to move genes from one species to another unrelated species and produce genetic combinations not possible in nature or obtainable by traditional breeding. While such transgenic organisms, known as Genetically Modified Organisms (GMOs), are safely confined to the laboratory there is no danger but there is legitimate concern about the possibility of their escape into the environment. In any case, if GMOs are to be of value they will eventually have to be used in fields or factories.
One way of assessing the possible effects of GMOs escaping into the wild is to regard this as an event similar to the deliberate or accidental introduction of an exotic animal or plant into a new country. Studies in both the UK and Australia show that about 10 percent of such introductions become established and about 10 percent of these become serious pests or weeds. Although only about one percent of introduced species become pests, they can cause dramatic changes in their new environment. British examples include the accidentally introduced pathogenic fungus causing Dutch Elm disease and the deliberately introduced Rhododendron ponticum.
It is clear that genetically modified animals or plants could become serious pests or weeds with considerable economic consequences. However, it is the microbial GMOs, bacteria and viruses, which are technically easier to produce that give rise to the most concern. Already there have been a number of trial releases of such GMOs although our knowledge of the ecology and population genetics of micro-organisms is much less than for higher plants and animals. This makes the prediction of their possible effects more difficult and more research in this area is urgently needed.
Any new procedure which involves the manipulation of the gene-environment interaction has an element of risk. It is therefore essential that the present cautious, case-by-case risk assessment continues and that there is no sudden, uncontrolled rush into the commercial exploitation of any GMOs.
Reference: The Release of Genetically-Engineered Organisms (1993). Published for the British Ecological Society by the Field Studies Council, Shrewsbury.
John Timson