Why produce GM crops?
- Crops can be made to resist pests and diseases, so they need less insecticide which is potentially less damaging to the environment.
- Crops can be modified so they are tolerant of herbicides making weed control easier.
- Crops that need less spraying may be safer for farm workers. This could be particularly valuable in developing countries. GM maize and cotton that produce a protein to kill insect pests are already grown in several countries.
- GM crops can be made to resist drought.
- Genetic modification can give us enhanced plants, such as:
- rice with added vitamin A
- potatoes with more protein
- food crops with reduced levels of allergens
- low-flatulence beans
- watermelons without seeds
- GM plants could also produce products such as plastics, or new vaccines and drugs. GM technology might be cheaper and cleaner than conventional chemical factories.
- GM bacteria that thrive on pollutants could help clean up soil contamination.
Set against these benefits are potential risks:
- Will genes from modified crops escape into wild plants, protecting them from their natural pests, or from weedkillers?
- Will GM crops disturb natural ecosystems and harm wildlife?
- Will they pollinate organic crops, invalidating their organic status?
- Will the management of GM crops affect wildlife?
Examples of genetically modified organisms
Natural born killers, but slow
Insects have their own diseases - natural viruses known as baculoviruses. These viral infections can be used to control insect pests but take time to kill their hosts so serious crop damage can occur before the control measures take effect. The viruses can be made to produce a fast-acting toxin by inserting a gene from another organism. For example, a naturally-occurring baculovirus, which kills caterpillars, has been modified with a gene from a scorpion. This enables it to kill the caterpillars of the cabbage white butterfly quickly. No such GM viruses have so far received approval for commercial use.
Plastic plants
Many plants produce natural fatty acids that accumulate in their seeds as energy stores. Plants can be genetically modified to produce more of particular fatty acids. For example, researchers are modifying oilseed rape to produce chemicals used in making biodegradable plastics, and coriander is being modified to produce more petroselinic acid. This acid is used in making detergents and nylon.
Dirt busters
Bacteria and plants are often used to help clean up contaminated land and water. An example is a bacterium called Pseudomonas that is good at eating up waste explosives. Scientists are trying to modify certain plants and bacteria to make them better at dealing with particular contaminants. But, at present, no modified dirt-busting bacteria are authorised for use in natural environments.