The British Government describes genetic modification as the altering of the genetic material in that organism in a way that does not occur naturally or natural recombination or both. Therefore genetic modification produces organisms that would not occur in nature, unlike farming methods such as selective breeding which could occur naturally. To opposers of GM foods this constitutes a fundamental difference. Genetic modification is when DNA fragments are transferred into different cells through either the natural ability of agrobacterium, ballistic impregnation, electroporation or using microscopic crystals to puncture holes in the cells.
One complaint against GM foods is the imprecise ways in which genes are combined, as listed above.
Plants are made up of between 20 000 and 80 000 genes and we know very little about how these genes are activated as an integrated whole. Genes and the proteins they make do not work in isolation and are extremely complex. Nevertheless, scientists have been putting barely genes into wheat to make it disease-resistant for most of this century. GM technology is not as new as it appears.
New advances in GM technology, however, lean toward a more unprecedented type of experiment. One example is of strawberries been made able to resist frost-damage through inserting a gene from a cold-water fish.
In cases such as this we are not even dealing with gene transference from the same kingdom. What people do not realise is that there are almost identical genes found in plants and animals, that there is a commonplace inheritance during evolution and in some cases there are natural mechanisms for transferring genes between unrelated species (in agrobacterium, for example). To illustrate this, humans share 50% of their genes with bananas. Therefore gene transferral between different species or, in fact, between different kingdoms, is not as unnatural as it sounds. Nevertheless, there are certainly a number of worrying possibilities. For one, maizes are being developed to contain antibacterial properties.
It is feared that if transferred to bacteria they could become resistant to antibacterial drugs.
Advances in GM technology may also yield advances in other areas of science. Experimenting with DNA, genes and cells may aid research into human DNA. For example, in Texas scientists found a chemical compound in the plant borage that produces gamma linolenic acid, which has been found to reduce heart attacks caused by cholesterol. Theoretically, this gene could be transferred to crops producing lipids, making fatty foods such as margarine and ice cream healthier and safer.
There are also environmental arguments used in support of GM foods.
Producing GM tomatoes uses less energy and water; herbicide-resistant crops reduce the amount of herbicide needed so it can be sprayed less frequently and intensively; pest-resistant cotton has reduced the use of pesticides on cotton crops in the US by up to two thirds. On the other hand it is thought that making farming more efficient may accelerate the damage to wildlife already done. At present, herbicides and pesticides have reduced numbers of grey partridge by more than 50% and removal of field margin and hedgerows has led to a decrease in populations of sparrows, skylarks and reed bunting.
It is evident that we must look at the impact of GM products on other organisms to provide a true assessment. Cross-pollination is a major worry, as it would cause non-GM crops to be contaminated with GM crop genes. Surrounding GM crops with plants of other species would significantly reduce this risk of cross-pollination but the danger is still there.
Boundaries between species have been established though millions of years of evolution and the worry is that these barriers will be destroyed with GM technology, leading to unpredictable events. With chemical pollution the substance will half a half-life but the problem with GM crops is that they are self-replicating. As with all crops they are designed to reproduce and will do so, unless modified not to.
Arguably the most worrying aspect of GM products is their unpredictability, as briefly mentioned before. In 1989 consumption of the supplement L-tryptophan, derived from GM bacteria, killed 37 and rendered 1 500 permanently disabled. The scientists of the company, possibly to cover their own mistakes, blamed the GM process .