Virtually every crop we eat have undergone hundreds of years of genetic modification by farmers and scientist in search of desirable traits. Selective breeding and hybrid strains have contributed immeasurably to farm productivity during this time. Over the past 30 years however, genetic engineering has been revolutionized. While before, a farmer wanting to develop a frost resistant tomato would be able to breed towards one only if the necessary genes were available somewhere in tomatoes or a near relative to tomatoes, modern biological engineering techniques overcome such restrictions.
Genetic traits from outside a species’ gene pool, in the tomato’s case from an arctic fish, can be spliced into the organism to create an entirely different species, a transgenic organism with the typical traits of a tomato and frost resistance from a fish. The most widely used method of gene splicing, recombinant DNA, uses biochemical “scissors” called restriction enzymes to cut the strings of DNA, selecting required genes. These are then “ferried” by a virus or a bacterium that infects the host, smuggling the gene into the plant’s DNA.
In this way scientists have been able to create slow ripening and seedless fruit, crops that grow in unfavourable conditions and are resistant to disease or herbicides and milk from cows given a genetically engineered growth hormone. The benefits of gene technology in terms of food production are enormous. The most common genetically engineered crops contain modifications that make the plants resistant to certain diseases and herbicides, or allow them to produce their own pesticides, thereby eliminating or reducing the need to spray.
So-called “Bt corn,” for example, contains a gene resistant to the harmful mycotoxin fungus and herbicide producers, Monsanto have created a strain of soybeans genetically modified to be unaffected by their product Roundup. The soybean farmer therefore can avoid targeting specific weeds and require just one application of a general weed-killer, reducing costs and agricultural waste run-off.
Genetically modified crops are also being adapted to grow in salty, dry or frosty environments, contain edible vaccines, have a longer shelf life and be more nutritious. A group of Swiss and German scientists recently developed a strain of GM rice know as golden rice’ due to its altered colour. Containing genes that produce a unusually high amount of beta-carotene (vitamin A), this rice could be a solution to the thousands of poor children in Asia who eat little but rice and go blind or die from lack of vitamin A Public reaction to the use of recombinant DNA in genetic engineering however has been mixed.
Sliding US export commodities such as genetically modified soybeans and corn have highlighted hardened public opinion and widespread resistance to biotech crops, especially in the European Union. Concerns about GM foods fall into three categories: economics, environmental hazards and human health risks. The latter two have been the subject of hot debate, both in Australia and overseas.
Environmental damage from GM crops can be caused through various channels. One of the main concerns has been the possibility of gene transfer to a non-target species, that is crops engineered for herbicide tolerance and weeds cross-breeding, resulting in the transfer of the herbicide resistance to create superweeds’. In addition, environmentalists fear that transgenic plants may proliferate rapidly, pollinating natural plants in their surroundings eliminating existing species.
Further environmental suspicions include those of unintended harm to other organisms (especially non-target insects) and of the reduced effectiveness of pesticides once insects become tolerant to a crop’s natural pesticide. Questions have also been raised on the human impact of genetically modified organisms. Critics of recombinant DNA fear that the pathogenic, or disease-producing organisms used in some recombinant DNA experiments might develop extremely infectious forms that could cause worldwide epidemics.
Likewise, the unknown effect of foreign genes introduced into GM food crops in terms of human health also presents a controversial issue. Furthermore, there is a possibility that introducing a gene into a plant may create a new allergen or cause an allergic reaction in susceptible individuals. A proposal to incorporate a gene from Brazil nuts into soybeans in order to increase their nutritional value was abandoned when it was found that the genetically engineered soybeans caused an allergic reaction in people sensitive to Brazil nuts.
For these reasons, extensive testing and labelling of GM foods may be required to avoid the possibility of harm to consumers with food allergies. Biotechnology has started to revolutionise food production, with fantastic results. With the world population of 6 billion expected to double in the next 50 years and an adequate food supply becoming a major challenge it will no doubt continue to do so in the future.