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genetically modified crops
background
It is possible to imagine the first farmers looking at their crops and thinking, 'These plants produce the best yields. Let's save them and use them as seed for next year. That will give us even bigger yields.' Then, one year, someone must have concluded, 'We bred a cow that produces a lot of milk with the biggest bull and the calf is even better - lots of milk and plenty of meat too.'
Plant and animal breeding technology have always been with us, as long as farmers have taken notice of what goes on in their fields.
The latest revolution in plant breeding is a result of the genetic modification (GM) of seeds. All living things contain DNA, a complex molecule that holds a genetic code for each plant and animal. DNA contains the instructions, inherited from previous generations, for building the organism. Genetic modification involves taking some of the DNA from one species and adding it to the DNA of another species. When a plant is genetically modified, one or more characteristics of the donor species are transferred to the new plant.
Plant and animal breeding technology have always been with us, as long as farmers have taken notice of what goes on in their fields.
The latest revolution in plant breeding is a result of the genetic modification (GM) of seeds. All living things contain DNA, a complex molecule that holds a genetic code for each plant and animal. DNA contains the instructions, inherited from previous generations, for building the organism. Genetic modification involves taking some of the DNA from one species and adding it to the DNA of another species. When a plant is genetically modified, one or more characteristics of the donor species are transferred to the new plant.
gm examples
Some examples of the methods by which new varieties can be developed include:
> adding the genes of a herbicide-resistant weed to a wheat seed to produce a type of wheat that is not harmed by herbicides. A field of wheat can then be sprayed to kill weeds without affecting the crop
> adding the genes of a species resistant to a particular pest to soya bean seed, so that the plant is not damaged by that pest
> adding a gene to a plant that grows well in an arid environment to the DNA of a rice plant. This could produce a plant that grows better in drier areas than traditional rice plants
> switching off undesirable genes such as those which make tomatoes go soft when ripe means that they will last longer so fewer are lost in harvesting. They hold less water which saves on watering in the growing process
> artificially made protein can be made to turn milk curd into cheese which does away with the need for rennet from calves' stomachs making vegetarian cheese
> adding the genes of a herbicide-resistant weed to a wheat seed to produce a type of wheat that is not harmed by herbicides. A field of wheat can then be sprayed to kill weeds without affecting the crop
> adding the genes of a species resistant to a particular pest to soya bean seed, so that the plant is not damaged by that pest
> adding a gene to a plant that grows well in an arid environment to the DNA of a rice plant. This could produce a plant that grows better in drier areas than traditional rice plants
> switching off undesirable genes such as those which make tomatoes go soft when ripe means that they will last longer so fewer are lost in harvesting. They hold less water which saves on watering in the growing process
> artificially made protein can be made to turn milk curd into cheese which does away with the need for rennet from calves' stomachs making vegetarian cheese
arguments in favour
> Those in favour of GM crops claim that newly engineered crops could solve food shortages throughout the world and could reduce the input of chemicals into farming.
> Trials of GM soya and maize have done well in the USA and some produce has been imported into the UK and used as animal feed.
> China has invested a great deal into researching GM rice and cotton crops. Rice is the staple diet for its huge population and cotton is an essential raw material for its clothing industry. Such developments are therefore important for both feeding its people and improving its level of development. It is no surprise that there is little opposition to GM crops in China.
> Trials of GM soya and maize have done well in the USA and some produce has been imported into the UK and used as animal feed.
> China has invested a great deal into researching GM rice and cotton crops. Rice is the staple diet for its huge population and cotton is an essential raw material for its clothing industry. Such developments are therefore important for both feeding its people and improving its level of development. It is no surprise that there is little opposition to GM crops in China.
arguments against
Trials in the UK have been conducted since 1999 but they have been controversial. Critics of GM have the following objectives:
> The pollen from GM plants might pollinate nearby plants and crops, spreading the modifications in an uncontrolled way.
> Crops on organic farms might be contaminated by pollen from GM crops, causing farms to lose their organic status.
> The long-term effects of GM crops on human health are unknown.
Protesters have destroyed GM field trials in the UK because of these fears. Campaigners want GM crops to be banned completely and point to agricultural innovations that have had serious health and economic effects, such as BSE. On the other hand, some farmers and companies see a great opportunity to make profits from GM crops. The UK government is encouraging further testing in laboratories, along with carefully controlled field trials. In the meantime, all GM crops that are sold to the public have to be labelled.
> The pollen from GM plants might pollinate nearby plants and crops, spreading the modifications in an uncontrolled way.
> Crops on organic farms might be contaminated by pollen from GM crops, causing farms to lose their organic status.
> The long-term effects of GM crops on human health are unknown.
Protesters have destroyed GM field trials in the UK because of these fears. Campaigners want GM crops to be banned completely and point to agricultural innovations that have had serious health and economic effects, such as BSE. On the other hand, some farmers and companies see a great opportunity to make profits from GM crops. The UK government is encouraging further testing in laboratories, along with carefully controlled field trials. In the meantime, all GM crops that are sold to the public have to be labelled.
the future
On a global scale, GM production is continuing in countries such as the USA and China. International seed companies and food manufacturers are unlikely to be influenced by protesters in one country. Similarly, within a free-trade environment such as the EU, it will be increasingly difficult for governments to regulate the import of GM seeds or products.
In less developed countries, farmers may well face similar problems to those caused by the Green Revolution. GM seeds will be available only from large seed companies and it will not be possible to save seeds from one year to the next because many crops are designed to produce infertile seeds. Poor farmers will not be able to compete with their richer neighbours.
In less developed countries, farmers may well face similar problems to those caused by the Green Revolution. GM seeds will be available only from large seed companies and it will not be possible to save seeds from one year to the next because many crops are designed to produce infertile seeds. Poor farmers will not be able to compete with their richer neighbours.
case study: the genetic code of rice
In 2005 the Institute of Genomic Research (TIGR) announced that it had finally unravelled the genetic code of rice. In previous years researchers had uncovered part of the sequence but after private companies Monsanto and Syngenta made figures available to TIGR, it was possible to complete the code. It is estimated that the DNA of rice has over 400 million base pairs holding around 40,000 genes, far more than are found in humans.
Rice is a staple food for around half the world's population but growing most varieties requires large volumes of water and, co,pared with similar crops, it is inefficient. Rice is also vulnerable to drought. The genomic data should speed up the breeding of tougher and higher-yielding varieties that can help feed the world's expanding population. Consumption trends suggest that 4.6 billion people will be reliant on rice crops by 2025, necessitating a 30% increase in production.
As the crop is closely related to other major cereal grasses including maize, wheat, barley, rice, sorghum and millet, it is hoped that this discovery will allow researchers to access the DNA of a range of cereal crops.
Rice is a staple food for around half the world's population but growing most varieties requires large volumes of water and, co,pared with similar crops, it is inefficient. Rice is also vulnerable to drought. The genomic data should speed up the breeding of tougher and higher-yielding varieties that can help feed the world's expanding population. Consumption trends suggest that 4.6 billion people will be reliant on rice crops by 2025, necessitating a 30% increase in production.
As the crop is closely related to other major cereal grasses including maize, wheat, barley, rice, sorghum and millet, it is hoped that this discovery will allow researchers to access the DNA of a range of cereal crops.