The Benefits of the use of DNA Technology in Agriculture outweigh the Disadvantages
There is much controversy surrounding the topic of genetically modified foods, a subject that provokes an emotional debate as some of the ideas contradict many moral and religious beliefs. Many ‘disadvantages’ are merely the moral views of people, and have little or no scientific link, such as the belief of consuming a plant with a human gene spliced into its DNA is an act of cannibalism. Any true disadvantages, however, are greatly outweighed by the benefits of the use of DNA technology.
Recombinant DNA technology involves the combination of DNA from one organism with DNA from another organism. For example desirable genes can be transferred from an organism to a crop plant. Firstly, the required gene is isolated, using one of three different methods. In one method, the amino acid sequence of the protein must be discovered and a genetic code can be used to work out the base sequence that codes for the protein. An artificial gene with complementary DNA is produced from the DNA with the base sequence of the protein.
Another method used involves the enzyme ‘reverse transcriptase’ which speeds up the production of complementary DNA from messenger RNA. When cells make a protein, the gene is transcribed into an mRNA molecule, which is used to produce the gene. DNA probes can also be used. This is a short strand of DNA carrying part of the base sequence of the desired gene, and is labelled with a radioactive isotope of phosphorus or with fluorescent dye to show where the gene is. Molecules of the DNA probe will attach to the complementary sequences of bases on the DNA in the organism.
The enzyme ‘restriction endonuclease’ which are made naturally by bacteria to destroy DNA of bacteriophages, removes the gene from its chromosome, cutting the DNA at different parts of the base sequence, in a recognition sequence. Once the gene has been isolated, it can then be inserted into the plant cell, using a vector to carry the genes into a cell, which is often a plasmid. Using the same restriction enzyme to cut open the plasmid produces complementary genes so that they pair together.
Under the right conditions, the genes and plasmids will join together, called ‘ligation’. The enzyme controlling this process is ligase. The main reason for genetically engineered crops is so that the plants have new, desirable qualities. The gene inserted into the vector could code for characteristics of the plant that would make it be easier to grow. The taste of the crop can be enhanced, and the shelf life and transportation can be improved by controlling ripening in products, such as melons, tomatoes.
Some advantages of using genetically modified crops are that the plants have an improved resistance to pests, and to bacterial, viral and fungal disease, using the plant equivalent of a vaccine. They also have an improved resistance to herbicides so that they are unaffected when herbicide is sprayed on the fields to control weeds. Plants can be made to able to resist the cold or drought, and genes can be inserted so that the crop is salt-tolerant. This quality would be useful particularly as global warming causes a rise in sea level.
The production of vitamins, minerals and anti-cancer substances can be enhanced by genetic manipulation, which can also enable plants to produce pharmaceutical substances, such as edible vaccines and anti-coagulant compounds e. g. bananas. Also anti-nutritional compounds and allergens can be removed. Research into the production of GMOs is currently underway over the world. There is international agreement that such crops will pass safety assessments before they can be grown.
Some aspects have to be taken into consideration, such as how the gene will affect the plant and if the toxicity and allergenic properties will be affected. The surrounding environment must be taken into consideration, as the plant could potential become a weed and invade natural habitats. However, despite this, many people are concerned about the risks of recombinant DNA technology, and any dangerous effects it could have to their health. A common belief is that pollen or seeds could ‘escape’ and be carried away from test plots, resulting in a genetically modified population elsewhere.
As some crops contain a gene for resistance to herbicide, the plant could become an uncontrollable ‘super weed’. Also, some plants have been given a gene enabling them to produce their own natural pesticide. However this may speed up the evolution of pesticide-resistant insects which would harm the environment as such insects would not be able to be controlled and new types of pesticides would have to be researched in order to control the insects. In the meantime the pesticide-resistant insect population would increase and damage vast quantities of crops.
It is believed that the genetically modified crops may cause new allergens and toxins in food, and that the increased use of chemicals on crops could result in the contamination of our food water supply. However, whilst research is still being carried on the consequences and implications of using genetic modified crops, any negative effects are not completely justified. For example, the effects on consuming a plant with genes inserted to a person 50 years after eating the plant will not be known yet, and any side-effects can only be predicted.
As the advantages of using GM foods are more immediate, the idea of producing crops with a gene to improve its qualities and marketing appears more attractive as the full extent of the disadvantages are still not yet fully known. People are still wary by the unnecessary negative press that GM foods have received. On the other hand, research could uncover more benefits to DNA technology and possibly methods of controlling any ill-effects the insertation of a new gene could have.