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| Answers on a green background are scientifically factual as of when this FAQ was last updated. These answers represent are as close to true as we can get. |
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| See Is DNA dangerous? in the general biology FAQ. |
| See Is DNA from genetically engineered organisms dangerous? in the general biology FAQ. |
| See Can DNA (from genetically engineered organisms) mutate me? in the general biology FAQ. |
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No, viruses are selective in what living things they can infect. Any
given virus can infect only a few species. There are no known viruses
that infect both plants and animals; the virus used to genetically
modify plants, (Cauliflower Mosaic Virus or CMV) doesn't
infect people. In fact, people are constantly exposed to CMV with no
ill effects: it's very commonly found on raw vegetables.
(Cauliflower Mosaic Virus is not the same as another CMV blood donors have heard of. That one is Cytomegalovirus, a retrovirus that is endemic in people. Most people carry Cytomegalovirus harmlessly, but it poses some hazards to pregnant women and people with poorly working immune systems.) See these topics in Life's Big Instruction Book: What's that? |
| See Can DNA "left over" from genetic engineering infect other organisms? in the general biology FAQ. |
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Any time a plant or animal starts making a new protein due to mutation there's
a possible risk that some people will
have allergic reactions to it. The risk is likely to be lower for novel foods
produced by genetic engineering than for other novel foods
produced by older forms of genetic manipulation, like artificial selection.
For genetical engineering to increase the the risk of allergies in food, a couple of things need to happen: first, the plant must produce something new. Many kinds of genetic engineering simply increase or decrease the amount of something a plant already makes. If somebody wasn't allergic to that before, they won't be allergic to that now. Second, the new stuff must end up in the part of the plant that people eat. If an apple tree is making bio-insecticides in its leaves, you're not going to be hurt by it (unless you like eating leaves). But what about the case where something new is ending up in food? The people who design new foods are aware of the possibility that new things might pose a risk, and they've developed strategies for minimizing or eliminating the risk of allergies. It's well known that allergies to protein in food are caused by over-reactions of the immune system in the small intestine, which is where the last stages of digestion occur. Genetic engineers therefore design new proteins to be digested in the stomach, at the first stage of digestion -- so that there's nothing else for the immune system in the small intestine to get upset about. (The immune system doesn't work in the stomach, as the strong acids and other digestive chemicals in it destroy the immune system's sentinels.) Genetic engineers maintain large databases of known allergens and use software to study new proteins to find and eliminate (or change) potential allergens in food. "Traditional" crops developed by artificial selection are largely unregulated and rarely tested for allergens. See these topics in Life's Big Instruction Book: What's that? proteins (workers), mutation, differentiation, artificial selection, genetic engineering |
| To greater and lesser extents, all
plants make their own pesticides. Plants that have been bred to
resist insects better probably make more pesticides, but we don't
really know in most cases. Some of the pesticides plants make do
sometimes make people sick. However, we rarely test conventional foods for
possible poisons until after there's been an outbreak of illness. In
general, only crops genetically engineered to make pesticides are well
understood, because somebody had to decide what pesticide they would
make, and in what quantity, and then test to verify that that's what's
happening. See these topics in Life's Big Instruction Book: What's that? |
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We don't believe that genetically engineered crops pose any new risks
compared to crops developed by artificial selection. Despite extensive
testing, nobody has found anything different between them that poses
a risk to human health.
Political opponents of genetic engineering occasionally claim to worry about subtle or long-term effects, and it is indeed possible that there may be some. It is also true that there may be subtle or long-term effects of any or all foods we eat. The scientific and mathematical tools to find such health risks have existed for only the past few decades, so it's not clear that we could find these risks for food developed by artificial selection, even if we had been looking. As far as we can tell, the enemies of genetic engineering want to label food produced by genetic engineering to instill fear in potential customers, by implying there is some difference. We might humbly suggest that food developed by older techniques be labelled, "This food contains genetic material of unknown purpose and function," or "This food contains unknown amounts of potential poisons and/or allergens," as both are true statements. However, such labels don't really benefit anybody in any way. See:
Can (genetically engineered) foods cause new allergies?
See these topics in Life's Big Instruction Book: What's that? artificial selection, genetic engineering
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| See What are the risks of genetic engineering? |
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Genetic change, regardless of cause, can change the kind and quantities
of nutrients food contains; so, certainly. The same is also true for
foods (both plants and animals) genetically modified by artificial selection.
Further, random mutation may also change foods' nutritional value. Indeed,
within any species of food plant or animal, there is some variation in
nutritional quality, as there is some variety in genes. In general, though,
nobody monitors these things.
See these topics in Life's Big Instruction Book: What's that? genetic variation within a species, variety (of a species), mutation, artificial selection, genetic engineering |
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Certainly. Most plants produce small amounts of poisons, to fight
off insects and diseases. Occasionally, mutation -- either spontaneous
or caused accidently via artificial selection -- has increased these amounts,
or led to plants producing poisons they hadn't before.
Two cases have been studied extensively. In one, a new variety of celery produced enough of a toxin (psoralen) to cause the field workers picking it to develop rashes. In another, a new variety of potato was discovered to contain a lot more the the toxic solanide glycosides than most other potatoes. Both of these crops were developed by artificial selection. In general, few foods are tested for poisons. In the cases mentioned above, the poisons were found only when people got sick. To date, no genetically engineered crop has unexpectedly produced poison, but this is a likely risk, if adequate testing isn't done. (See How are genetically engineered crops designed?) It isn't likely, though, since the genetic changes introduced by genetic engineering are better understood than those of artificial selection. |
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We think all novel crops should be tested, especially those developed by open pollination, since the least is known about their genetics. |
| See these topics in Life's Big Instruction Book: What's that? mutation, artificial selection, genetic engineering
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Probably. Unfortunately, it's unlikely to make them worse. It's unfortunate
because bioweapons developed by artificially selecting
diseases are already extremely lethal. As far as we
know, all existing bioweapons were developed by artificial selection.
However, there's no way we can say for sure that no evil people will try
to use genetic engineering to make bioweapons.
See these topics in Life's Big Instruction Book: What's that? bacteria (prokaryotes), viruses, artificial selection, genetic engineering |
See these topics in Life's Big Instruction Book: What's that?
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