✔ 最佳答案
Genetically-modified (GM) food is produced from plants or animals which have had their genes changed in the laboratory by scientists.
All living organisms have genes written in their DNA. They are the chemical instructions for building and maintaining life. By modifying the genes, scientists can alter the characteristics of an organism.
We might, for examples, want to boost yields, increase muscle bulk and make our crops and farm animals resistant to disease. Genetic engineering holds out these possibilities.
However, the technology is in its infancy. Very few food crops have been gene-altered using the new techniques, and there are no foodstuffs on sale in the UK made from GM animals.
And none of the GM crops currently being commercially grown around the world contain genes transferred from animals or humans.
Some will argue that this new technology is "unnatural". Others will point to the commonality that exists between species - from bugs and worms to monkeys and humans, we already share many of the same genes.
The first transgenic plant - a tobacco plant resistant to an antibiotic - was created in 1983. It was another ten years before the first commercialisation of a GM plant in the United States - a delayed-ripening tomato - and another two years (1996) before a GM product - tomato paste - hit UK supermarket shelves.
1996 was also the year that the EU approved the importation and use of Monsanto's Roundup Ready soya beans in foods for people and feed for animals. These beans have been modified to survive being sprayed with the Roundup herbicide that is applied to a field to kill weeds.
This soya, together with GM maize, is now used in a variety of processed foods on sale in UK shops. The products range from crisps to pasta.
A genetically-engineered version of the milk-clotting enzyme chymosin is also used in cheese-making.
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http://news.bbc.co.uk/1/hi/special_report/1999/02/99/food_under_the_microscope/280868.stm
http://www.askcab.co.uk/youth_site/gmfoods.asp
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