Introduction:
Genetically modified foods are made from the genetically modified organisms that have had their DNA altered by genetic engineering. This form of manipulating the genes for a new form of crop is a very new technologic advancement. Biotechnology offers the ability to do this by transferring the desired trait by manipulating the genes from one plant to another.(2) This process is very fast and selective when compared to other traditional methods. Which take number of years to transfer the desired gene trait by genetic breeding. The most common genetically modified plants are soybean, corn, wheat, cotton, and canola .These are some of the important crops that are being genetically modified. Genetically modified crops are given so much importance because they have a huge potential to revolutionize the whole agriculture industry. Their advantages are that they improve the crop production and the yield tremendously. This increase will improve the farmers using GM crops economically and financially, Thus the nation on the whole. Most of the GM grains are about disease and insect resistance so naturally the use of insecticide and the use of other chemicals will go down. By this the strain in the environment is lessen. In this modern world where there is a huge population increase, this new technology will help in meeting the incredible demand for food. They also have certain drawbacks which make them controversial. But most of them are about health hazards caused by long term use of genetically modified organism. (8)
Developing a GMO plant (grain):
Transgenic plants are produced by a method called transformation where one or two genes that are responsible for a desired trait is added to the plant genome. They use gene guns to transfer the DNA by means of microscopic tungsten gold particles. The DNA is literally shot into the nucleus of the plant. The second method is by horizontal gene transfer with the help of soil bacterium known as Agrobacterium tumefaciens(3).In the second method the desired gene is attached to the plasmid vector which then transfers the genetical material to the plant cell. Plasmids are extra chromosomal DNAs which are capable of replicating independently to that of chromosomal DNA .They are found in bacteria's and they have single origin of replication. There is a need to use plasmid vectors to insert gene into the cell because when we normally just insert the gene alone it will get digested by the cells enzyme. Hence we use plasmids which resist the digestion by the enzymes and transfer the gene in a beneficial way.(3)
Source: http://bio.kaist.ac.kr/~mbtlab/Lecture01.htm
http://www.premierbiosoft.com/images/plasmid_maps.gif
The gene is attached to the plasmid by few steps .first the gene and plasmid have a special sequence called recognition sequence(here Eco r1) . Both the plasmid and the gene are cleaved at that point using the molecular enzyme called DNA endonuclease .Then the gene and the Plasmid are joined together by another enzyme called DNAligase. Source: http://www.accessexcellence.org/RC/VL/GG/inserting.php
Then after this process the recombinant plasmid is injected into the bacteria like Agrobacterium tumefaciens. Then the bacterium is put into the plant cell by genetic engineering and then the desired gene gets attached to the plant genome and starts expressing its properties(3). Then the transformed plant cell is tissue cultured and new generation of transgenic plants are produced. The whole process is clearly explained by the below diagram:
Common GM grains:
America (67%), Canada (24%) and Argentina (8%) are the most common users of GM crops .And some of the mainly used GM grains are Soybeans, cotton, rapeseed, Corn, sweet corn, rice and canola. Usually the most common GM plants are modified to be disease, insect or pest resistant varieties. Apart from this there are also the famous draught tolerant and insecticide tolerant plants which get their genes either from a plant that exhibits these characteristics or from bacteria's. In Australia the only GM crop that is used is cotton and the GM cotton alone accounts for 80%.Whereas the GM canola is yet to be released in western Australia buts its already being cultivated in Queensland and Northern territory .In other states special committees have been setup to study the impacts of GM canola. The GM wheat that was developed was totally rejected by Australia due to some flaws in it.(6)
The table of the most common GM grains
Source: http://en.wikipedia.org/wiki/Genetically_modified_food
Golden Rice:
Golden rice(1991) was developed as a Humanitarian tool to save the people suffering from vitamin A deficiency around the world and mainly for the people of Africa. The principle behind it was to biosynthesize beta-carotene which was the precursor of vitamin A .This was possible because the beta carotene gets digested in the intestine and gets converted into retinol. The whole rice plant produced beta carotene except its endosperm .Hence the scientist incorporated three genes; two from daffodil and one from a bacterium. After this incorporation, even the endosperm started producing beta carotene. Lets now see the overview of the carotenoid biosynthesis pathway in golden rice.
Source: www.goldenrice.org
psy (phytoene synthase) from daffodil (Narcissus pseudonarcissus)
crt1 from the soil bacterium Erwinia uredovora .
Its called golden rice because of its colour due to the production of beta carotene.
Source: www.goldenrice.org
Later it was opposed strongly by people and organizations from different part of the world due to the unknown health hazard it might cause when used long term but it was simply a paranoia. The main reason that was quoted to ban its use was that it didn't produce enough beta carotenes to be converted into vitamin. Hence it was banned for human consumption. Later to rectify this flaw, again the scientist developed the Golden rice 2(2005) which produced 23 times more beta-carotene than the original variety of golden rice. But still the opposition was there for it so neither of the two varieties is being used for human consumption.
Source: http://www.goldenrice.org/Content2-How/how1_sci.html
GM-Cotton:
The only GM crop grown in Australia is cotton. It was first released in the year of 1996 and now it accounts for 80% of the total cotton plantings in Australia. Insect resistance and herbicide resistance are the new traits of the GM cotton. The Gm cotton is also known as BT cotton because it is modified with the help of the bacteria called Bacillus thurigenesis.The above mentioned bacteria produces a endotoxin which attaches itself to the cell linings in the gut of the insect like boarers and prevent the digestion process .Thus the insect die of starvation. In BT cotton manufacture the endotoxin producing gene from the bacteria is taken and attached to the plant by the normal methods mentioned before. Thus enabling the plant to produce the same toxin by which it kills the insect that eats its leaves. By using this cotton variety the insecticide use in Australia went down by 85% compared to the conventional varieties.(6)
GM-Canola:
Gm canola has been introduced in two states in Australia .They are Queensland and northern territory in other parts of Australia its still under feasibility studies. The GM canola that's been released is herbicide resistant .So herbicides can be used without damaging or killing the plant. The huge talk about GM canola is because if introduced they will improve the yield by 7% compared to the conventional breed. And also they will reduce the production cost by 3%.The incredible thing is that the total canola production will go up by 9% in 2010.Another boost to the economy is the increase in oil export by 12%. (6)
Advantages of GM grain:
As previously discussed they will increase the grain yield ,decrease the strain on environment , improve farmers financial status ,and help to meet the incredible demand for food .Above all the latest GM grains have huge health benefits like increased nutrients and also incorporation of vaccines in GM plants. These kinds of vaccines are called biovaccines and it's a huge technological advancement in the field of biotechnology. These are some of the important benefits of a GMO.(1)
Drawbacks of GMO:
Unknown health outcome: As GM is a modern technology, the impact it can cause on health because of long term use is unknown. This is the first reason for many to oppose the GMO.
Identity preservation: By genetically engineering the plant we are manipulating the originality of the plant. For example, Golden rice is no more a rice because its genome contains 2 genes from daffodil and one from bacteria. Thus the identity is lost .
Terminator technology: Some GMO have been manipulated so that they become sterile in their second generation hence its not possible to breed them. This technology leads to the so called monopoly.(4)
“The problems of consumer acceptance of GM products arise from perception of their safety as food, the risks that they could pose to the environment, ethical concerns and the potential for a limited number of companies to exert control over the food supply chain.”(6)
Conclusion:
GMO grains have huge benefits when compared to the drawbacks .The number of advantages has far outweighed the drawbacks. But the paranoia among public is mainly because of lack of awareness or knowledge about GMO .So steps should be taken to educate the people about the GMO and its benefit. The press should take up more responsible role and help the scientific community in their awareness spreading campaign .They should stop exaggerating rumors about GMO which is the main reason for the paranoia among people. Also should involve in accurate reporting of current facts to the public. Because such a technology should at least be welcomed with open mind, when not with open arm.(3)
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