- Q What does it mean if a food or crop
is genetically modified? A That the DNA in its cells has been altered to
add genes from other organisms, such as bacteria, other plants or even
animals. (The "antifreeze" genes that fish produce has been added
in experiments to some plants, though none is on sale.)
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- Q How is it done? A Either by using a
naturally occurring plant virus to "infect" the target plant
with the new genes, or by literally firing the extra DNA on tiny gold beads
into the cell nucleus, where the DNA resides. Neither method is precise,
but once the new genes have been successfully added, the cell can be multiplied
to produce a brand new plant that nature could not have. This does not,
however, make it a "mutant": those are naturally occurring.
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- Q Is the controversy about how genetically
modified foods might affect us if we eat them, or about how genetically
modified crops might affect the environment while they are growing? A Both.
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- Q What's the difference between genetically
modified, genetically engineered and transgenic? A None - they are synonyms.
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- Q What are the main ways in which plants
are currently genetically modified? better. But for growing, they can be
modified to be tolerant of large amounts of powerful weedkillers and insecticides
which would otherwise kill them. That potentially means increased productivity.
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- Q What are the fears arising from these
modifications? A For foods, that we might swallow something with genes
which could behave unpredictably - for example, somehow mixing with bacteria
in our stomach to produce a strange new organism. DNA has a half-life of
about 10 minutes in the stomach, so some of those fears have a basis in
fact. But processing, such as turning a crop into oil, destroys the DNA.
For growing, the worry is that the powerful pesticides will kill everything
else in and around the field, such as wildflowers and insects, and thus
the bird life which depends on the seeds and grubs. The genes for pesticide
resistance might also cross into wild plants, creating an "arms race"
in that more, rather than fewer, pesticides have to be used to suppress
weeds.
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- Q What sort of food is currently genetically
modified? A You can buy tomato puree made from tomatoes modified to stay
fresh longer. Some vegetarian cheeses are made with genetically modified
bacteria, which carry out the same function as rennet, the animal protein.
But many breads, biscuits, cakes and other foods may contain traces of
modified soya: about 30 per cent of the soya beans grown in the US, the
world's major producer, are modified to be resistant to a particular herbicide.
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- Q Why doesn't the Prime Minister back
a moratorium on the commercial growing of GM crops, if the Government's
official adviser, English Nature, does? A We do not know. At Prime Minister's
Questions on Wednesday, he took the line that ministers in trouble often
do, which is that they are "following the best scientific advice".
The problem is that on this topic, the advisers are divided. The Advisory
Committee on Releases to the Environment (Acre) thinks no moratorium is
needed; English Nature does.
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- Q If GM crops are so safe, why do they
need all these planting trials and so many regulations? A Because of scientists'
worries that cross-pollination with wild plants will lead to the new genes
spreading uncontrollably.
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- Q Will they? A Nobody knows for sure.
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