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Sunday, 26 February 2012

Genetically Modified (GM) Foods

 Genetically Modified (GM) Foods ::.

IntroductionThe Term "Genetically Modified (GM) foods" refers to crops produced for human or animal consumption using the recombinant DNA techniques. The world population is growing in a fast pace such that it is expected to double in the next 50 years. Supplying food to this growing population is a major challenge. GM foods can be considered as the major solution for the food security. These foods are produced by the modification of crop plants in the laboratory to enhance desired traits, mainly biotic and abiotic stress tolerance, improved nutritional content, etc. These traits were earlier carried out through conventional plant breeding, but these breeding methods are very time-consuming and often not very accurate. However, with recombinant DNA technology, plants with the desired traits can be produced, very rapidly and with greater accuracy.

ProcessRecombinant DNA technology begins with the identification and isolation of a gene which expresses a desirable trait, with the aid of restriction enzymes. Then a recipient plant or animal is selected, and the gene is inserted and incorporated into its genome through a vector such as agrobacterium, through a gene gun shooting an elemental particle covered in plasmid DNA, electro oration, or a virus. Once part of the recipient, the newly inserted gene becomes part of the genome of the recipient and is regulated in the same way as its other genes.

For example, we can isolate a gene responsible for conferring drought tolerance, introduce that gene into a plant, and make it drought tolerant. Crops can also be transformed using non-plant genes such as the use of Bt genes, in cotton and many other crops. Bt, or Bacillus thuringiensis, is a naturally occurring bacterium that produces crystal proteins that are lethal only to insect larvae. Bt crystal protein genes have been transferred into cotton, soya, corn, brinjal, enabling the plants to produce its own pesticides against insects such as the American bollworm, European corn borer. Bt genes are lethal only in the acidic medium, insect gut environment and do not get activated in an alkaline environment, prevalent in humans and other animals that feed on these plants.


Drought tolerance/salinity tolerance:
As the world population grows and more land is converted for housing instead of food production, farmers need to grow crops in non-arable land, previously unsuited for plant cultivation. Creating plants that can withstand long periods of drought or high salinity in soil and groundwater will help people to grow crops in large, barren wetlands/dry lands in our country.

Pest resistance: 
Insect Pests are causing devastating financial loss for farmers, sometimes starvation. Indiscriminate use of pesticides is also a potential health hazard, and the run-off of agricultural wastes from excessive use of pesticides and fertilizers poisons the water supply and harms the environment.

Ex: Growing GM foods such as Bt brinjal helps reduce the application of pesticides substantially, as 80 per cent of brinjal crop are infested with pests.

Disease resistance: There are many viruses, fungi and bacteria that cause plant diseases and thereby contribute to yield loss. Plant biologists are working to create genetically engineered plants with resistance to these diseases.

Ex: Developing sheath blight resistance in rice.

Cold/heat tolerance:
Farmers are facing the vagaries of weather, like unexpected frost or excess heat due to climate change. Researchers have identified an antifreeze gene from cold-water fish and introduced it into plants such as tobacco and potato to study the efficacy of the plant to withstand extreme temperatures. Also, research is on to identify plants that can survive excess heat, submergence tolerance etc.

People in our country suffer from various nutrient deficiency diseases due to malnutrition. Most of the people rely on rice as a major staple food. But rice does not contain adequate amounts of all necessary micro and macronutrients. If rice could be genetically engineered to contain additional vitamins, iron and/or minerals, nutrient deficiencies could be alleviated. For example, MSSRF (M.S.Swaminathan Research Foundation) are working on improving the iron content.

Soil and groundwater pollution continues to be a problem in many parts of the world.Plants such as poplar trees, brassica spp are being genetically engineered to clean up heavy metal pollution from soil contaminated with metals like lead, arsenic, and cadmium.


Most concerns about GM foods fall into three categories

Environmental hazards:
Unintended harm to other organisms; reduced effectiveness of pesticides; gene transfer to non-target species are some of the concerns of the environmental concerns of GM crops.

Human health risks:
Allergenecity, unknown effects on human health are some of the main health concerns.
For example, Pioneer Hi-Bred tested the allergenicity of a transgenic soybean that expressed a Brazil nut seed storage protein in hope that the seeds would have increased levels of the amino acid methionine. The tests (radio allergosorbent testing, immunoblotting, and skin-prick testing) showed that individuals allergic to Brazil nuts were also allergic to the new GM soybean.

Economic concerns Environmental activists, religious organizations, non-governmental organizations have criticized agribusiness for concentrating on profits through GM Foods without concern for potential hazards. They also criticized the government for failing to start a regulatory body. All GM crops should be subjected to thorough regulatory processes and toxicology and allergenicity tests data needs to be shared with the regulatory authorities prior to commercialization.

Government RoleMany new plant genetic engineering technologies and GM plants have been patented, and patent infringement is a big concern of agribusiness. So, bringing GM food to market is a lengthy and costly process. This is a genuine concern and therefore it is important for the government to fund and support public sector research in reputed universities or agriculture institutes to ensure quality research and also keep prices under check.

ConclusionGovernment should check all the hazards, environmental, health and economic concerns and then decisions should be taken to commercialize a GM product. Though ambiguity during the process, once they get regulatory approve, it implies that they have been subjected to stringent scrutiny and are safe for commercial release. So, the governments around the world are hard at work to establish an effective regulatory process to monitor the effects of and approve new varieties of GM plants.

According to M S Swaminathan, the chairman of the National Commission on Farmers, GM foods have the potential to solve many of the world's hunger and malnutrition problems, and can protect and preserve the environment by increasing yield and reducing reliance upon chemical pesticides. Yet there are many challenges ahead for governments, especially in the areas of safety testing, regulation, international policy and food labeling.

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