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The term "genetically modified" has been named inappropriately. Humans have bred plants and animals for thousands of years. By selective breeding, we have built into animals and plants gene combinations not usually found in nature and that would most likely not survive without human intervention. "Genetically modified" is currently referred to plants and animals that result from adding genes, in particular genes from completely unrelated organisms, to preexisting plants or animals. Genetically modified plants are commonly grown today in the United States. Most of the corn, soybean and canola derived products sold in this country are the result of plants engineered with recombinant genes. The most common genetic modifications are those that present resistance to certain insect pests and those presenting resistance to certain herbicides. So how is genetic modification of plants achieved?
The first step in genetic recombination would be to extract the piece of DNA that has been found to obtain the desired characteristic. The two most widely utilized genetically transplanted characteristics have been herbicide tolerance and insect resistance. (Anderson, L, 1999). Herbicide tolerance means that the GM crop can be sprayed with a wide range of herbicides that will kill most types of weeds, but will have no effect on the crop. The main types of these are ammonium glyphosate, marketed as "Roundup" by agricultural company Monsanto and ammonium gluphosinate used by global enterprise "Bayer". They are supervised by US and European regulators and are considered as benign compared to other herbicides. Although for fans of organic food there is no such thing as a benign herbicide. Many types of herbicide tolerant crop are available including corn, soya, canola and sugar beet. Out of all the previously mentioned herbicides, soya has been the most successful. The main producers of soya are USA, Brazil and Argentina. However, Brazil's crops are not as genetically modified as the USA and Argentina. Herbicide tolerant canola is grown in the USA and Canada. (Anderson, L, 1999)
GM insect resistant crops give off a toxin in their pollen that kills insects. This protection mechanism is very effective for the crop would've probably been eaten without it. The insect resistant crops are actually referred to by the name of the bacteria, bacillus thuringiensis. The most popular Bt crop is cotton which is grown in the USA, South Africa, India, China and Australia. Its relatively rapid spread to these countries must be explained partly by the fact that it is not a food crop. This makes the product much less controversial than GM food crops and makes it more tolerable. Bt versions of food crops is also available in crops such as corn and potatoes which are widely grown in the USA and Argentina. (Anderson, L, 1999)
Despite the start of GM food crops in the USA, Canada and Argentina, the anticipated spread of GM food technology is yet to happen. People most likely have a misconception of 'trials' for commercialization. In China, for example, there have been a large number of trials of a number of GM crops (Huang et al. 2002:675); however, these did not seem to have resulted in widespread commercialization. In the case of Bt cotton, it was a success. Trials do not automatically lead to commercial planting due to the fact that GM plants which are the subject of trials may not be suitable for commercialization, they may not be licensed, and they may simply not be grown because there is no market for their products.
Pests and insects are mostly found in the soil which is why herbicide tolerant and insect resistant characteristics are linked to bacteria found in there. DNA segments are extracted from chromosomal string these bacteria and cut by restriction enzymes, these are used to resist attack from viruses. The sought genes are separated, and then tied together into plasmids which are independent collection of genetic information. The chromosomes are enhanced in bacteria, and the desired characteristic is added to the DNA chain in the plasmid by the help of ligase enzymes. The linkage of these plasmids is crucial for these are the agents which carry the required genetic information for implantation into the target plant cells.The collections of DNA that will be transferred to the plant needs to be recognized so these are marked so that the new DNA recombination plant cells can be segregated from the regular plant cells. The segregation process consists in the isolation of the plant cell containing the recombinant. The cell culture is doused with an antibiotic. The cells that do not carry the antibiotic resistant genes die. (Pusztai, A, 2002)
Now Days, new types of markers have been developed. The most used is a method that includes genes that enables the recombinant containing cells in the presence of manose, a sugar, to grow while the regular cells do not grow. The cells that do not grow are useless while the cells containing the required genetic recombination are used. (Pusztai, A, 2002)
However, before all these processes take place, the genetic markers and the genes containing the new trait need to be transferred to the target plant cells. There are different ways of doing this. One way, involves a bacterium agrobacterium tumifaciens which is used to transfer the DNA' (Mayer 2000:97). This bacteria cause root and stem disease normally, and it is thus quite effective at penetrating plant cells. Genetic engineers use this bacterium as transfer mechanism of the genetic marker and new DNA recombinant to the plant cells. The cells which have been recombined with the new DNA will be separated from the rest and they can then be grown into full sized plants. Then seed can be produced and the product can be tested and, much later, marketed. Some plants resistant to roots and stem disease need to be approached by genetic engineers with the alternative of firing gold particles, coated with the plasmids, directly into the cells.
Being one of the sectors that use GM plants excessively, the United States never cease to stop experimenting and running trials for new discoveries. From trials that are currently taking place, it is obvious that future developments will base on finding diversity, increasing nutrition nutritional values, creating medicinal supplements and last but not least moving up to create genetically modified animals. By increasing diversity engineers are looking forward on creating virus and epidemic resistant GM technology that will save plants that are in endangered species such as the banana. This will be achieved by developing new crop strains that have advantages for farmers such as crop varieties which are resistant to various types of disease. Increasing the quality traits of nutrition to the user, such it's been the case of Golden rice being developed in India. By the biopharming medicinal supplements should be produced. After mastering the modification of plants for its better adaptation and facilitation of human life enhancement and survival, it is time for engineers to move up to enhance animals. (Kishaw and Shewmaker 1999:5968).
Future development of agricultural technology faces some barriers, but its biggest problem comes from consumer resistance. Unfortunately for the biotechnology industry, Europeans are very skeptic about GM foods. Even though most of the population is vegetarian, influenced by moral and religious connotation, in India the sale of GM food is actually illegal. China being one of the most advanced technological countries have held high hopes for biotechnologist, but this have been disappointed for the commercialization of GM food technology seems to have delayed. In fear of losing clients due to the preference of organic foods over GM foods many farmers have opted not to grow GM crops. Even though the United States is highly supported by the World Trade Organization, however food markets are declining because the key to victory is the acceptance of the consumer and day by day people become more and more scared of consuming GM foods.
- Anderson, L. (1999) Genetic Engineering, Food, and Our Environment - A Brief Guide, Totnes, Devon: Green Books.
- Kishaw, G. and Shewmaker, C. (1999) 'Biotechnology: Enhancing Human Nutrition in Developing and Developed Worlds', 'Plants and Population: Is there Time?, Proceedings National Academy of Sciences, volume 96, pp. 5968-5972, May 1999, Colloquium Paper, Washington, D.C.: National Academies Press
- Mayer, S. (2000) 'Genetic Engineering in Agriculture' in Huxham, M. and Sumner, D. (eds) Science and Environmental Decision Making, Harlow, Essex: Prentice Hall, pp. 94-117.
- Pusztai, A. (2002) 'GM Food Safety: Scientific and Institutional Issues', Science As Culture, volume 11, no. 1, pp. 69-92.