Issues surrounding genetic modification have stirred up a lot of controversy in recent years. Throughout most of the world, activities using live genetically-modified organisms (GMOs) are now controlled by law.
It is important to note that it is not the techniques of genetic modification that are controlled by law, but rather the uses of living organisms produced by these procedures. Under current legislation it is an offence to release any GMO into the environment or to allow it to escape without prior consent of the Secretary of State.
In practice, not many people are concerned about minor modifications of bacteria or yeast to produce drugs or other products. Similar practices have been common for two decades, and the organisms concerned are restricted to laboratories and production plants. They are very unlikely to 'escape' into the environment, and are unlikely to have an impact even if that did happen. For example, an insulin-producing bacterium would neither suffer harm nor enjoy benefit in the wild.
Modification of plant or animal DNA is more controversial. For example, negative media publicity about genetics surrounded the birth in 1996 of the cloned sheep 'Dolly' at the Roslin Institute in Scotland - despite the fact that although Dolly was a clone, she was not genetically modified in any way! Alteration of animal DNA is still in the experimental phase, and controversy may have made scientists reluctant to push this type of work very far.
The genetic modification of plants, particularly crop plants, has had an enormous impact on the public consciousness. Governments, biotechnology companies and environmentalists all have their own views on the pros and cons of the practice of modifying plant genetics, for example to make them pest or drought resistant plants.
The use of pesticides has long been controversial. For some background on this issue, you can read more in this story on the use of DDT and the birth of environmental movements.
SCENE: Silent Spring and the story of DDT
GM crops raise a wide variety of other issues and arguments. Firstly, that the spread of GM crops will be uncontrollable. Once a genetically modified crop plant is introduced into the environment, it is capable of passing on these genes in its pollen. Wild relatives of that plant could be affected by the pollen, and inherit some of the characteristics. Also, if farmers find the GM crop productive and useful, non-GM crops could become scarce - the only remaining food will be the products of these decisions.
Anxieties about eating GM foods may be exaggerated. Millions of people over the world have eaten millions of tonnes of GM food products over the last decade without a single documented case of ill effects. It is also worth pointing out that people eat the DNA of their everyday food with no transmission of genes from food to human. In theory any 'modified' genes we eat will similarly have no effect on us.
The key advantage of GM crops is that drought and salt resistant plants could be cultivated in areas where virtually no plants will grow at present, creating a food supply for whole populations of people who struggle to farm enough to eat. Additionally, specific benefits can be introduced. Rice modified to contain vitamin A via beta carotene could prevent millions of children going blind from vitamin A deficiency.
But the promise that GMOs could 'feed the world' has not yet become reality. The business aims of the companies producing the modified seed may not coincide with the best interests of those who would most benefit from the products.
You can look at the GM debate in more detail in the following activity.