GM foods are being grown in many countries. But different people have different things to say about their safety. Opinion is divided among scientists, consumers, environmentalists and politicians about whether or not GM food should be consumed. Why is there such a controversy? This article outlines the basic issue, and weighs the benefits of modified foods against the harmful effects.
Genetically modified foods, (also known as GM foods or biotech foods), are foods obtained from organisms that have been genetically modified by introducing changes in their genetic material, or the DNA.
Humans throughout history have been trying to modify and improve the yield and hardiness of crops in a natural way - by selective breeding of two varieties with desirable traits. But this type of breeding is random and slow. Along with the desirable traits, many undesirable traits can also be introduced in the offspring, and it can take much more cross breeding in many more generations to filter out the undesirable traits.
On the other hand, when genetic engineering techniques are used, the desirable traits can be introduced into the organism quickly and precisely. The technique consists of isolating the gene with the desired trait from one organism and introducing it into the DNA of the target organism. Thus, the DNA is altered and this altered DNA is passed on to the successive generations and hence, the desired trait is also passed on. However, the main difference between natural cross breeding and genetic modification is that in the former, organisms of the same species or very closely related species are crossed, whereas in genetically modified crops, genes from distant species can also be introduced.
Some examples of genetically modified crops are -
1. A breed of strawberries modified to withstand the extreme north European cold. An anti freezing protein found in the DNA of a fish was introduced in the strawberries.
2. The Bt cotton which has a gene from a bacterium known as Bacillus thuringiensis. This gene makes the cotton plant resistant to the 'heliothis' caterpillar and hence increases the yield.
3.The golden rice, which has been combined with betacarotene and therefore helps to prevent vitamin A deficiency in children.
- GM crops are more resistant to pests than ordinary crops and therefore less pesticides have to be used. They are more economical to the farmer in the long run, even though initial costs are high. GM crops are beneficial to consumers as well because less pesticides have been used on them.
- Decreased use of pesticides and herbicides is beneficial for the environment as well.
- GM crops have higher yield per hectare, are less dependent on fertilizers, produce harvest despite adverse weather conditions like drought or extreme temperatures.
- Modified crops are more resistant to diseases.
- GM cows produce more milk. Animals can be genetically modified to grow faster and require less food.
- GM foods can cause unknown health issues in animals and humans.
- GM plants which are engineered to be tolerant to herbicides can cross breed with closely related weeds and produce herbicide tolerant "superweeds".
- Consumption of GM foods by humans can trigger new allergies and introduce new toxins.
- DNA from viruses and bacteria is used to modify some crops. This could introduce new diseases in humans.
Modified foods do have many advantages, and an equal number of risks associated with them. The debate over the advantages and disadvantages continues. The tests that have been done on modified plants only measure the short term effects. There is not enough data yet to study the long term effects on human health and environment. The introduction of genetic material from one organism in another can have dramatically different effect than that envisaged by scientists. Until more conclusive studies can be done, GM foods should be clearly labelled and their consumption should be an individual's personal and informed choice.
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Readers's Digest Nov 2010