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According to the ISIS Report (www.isis.org.uk/sapp.php),
the issue of genetically modified organisms (GMOs) is an area that
cries out for application of the precautionary principle, if only
because so much damage can still be prevented at this stage. The
most commonly raised objection to the introduction of genetically
modified crops is ecological, that the genes may spread to other
species. That is indeed a danger; more than that, it has already
happened. In Canada and the United States the genes that make oil
seed rape tolerant to herbicides have spread to crops and weeds,
which end up tolerant to multiple herbicides. That makes the
herbicides useless and the weeds harder to control than before.
But while the ecological problems
are real, and have attracted the most attention, they are by no
means the whole story. The technology itself is a cause for concern.
To be sure, hardly anyone is likely to die immediately after eating
GM food. Apart from acute toxins and allergens, any harmful effects
are likely to appear only in the longer term. There is evidence that
many of the Bt toxins engineered into GM crops as biopesticides are
actual or potential allergens for human beings, and toxic to a wide
range of beneficial species. But it will be very hard to identify
these and other effects by epidemiological studies because there is
no control group.
There is evidence strongly
suggesting that GMOs are hazardous. First, transgenic DNA is not, as
is so often claimed, “just the same as natural breeding.” It is
different. For example, when researchers created mutants for
herbicide tolerance both by genetic engineering and by conventional
mutagenesis, they found that the transgenes were up to 30 times more
likely to spread to wild-type plants. The more rapid spreading of
transgenes is a potential hazard in itself, but what is crucial here
is the demonstration that the transgene was different. Genetic
engineering is not merely reproducing what happens in nature, and it
is creating new combinations of genes that have never existed.
Transgenic DNA can also be
transferred (horizontally) to unrelated species, to bacteria in the
soil or in the gut and to cells of all animals including humans.
When mice were fed viral or transgenic DNA, not only was the DNA not
completely degraded in the gut (as we used to be assured it would
be), it passed through the wall of the intestine into the blood
stream and even became incorporated in the genome of some mouse
cells. When fed to pregnant mice, the foreign DNA was found in some
cells of the fetuses and newborn, showing it had gone through the
placenta.
The researchers raised concerns
over the possibility that transgenic DNA integrated into human cells
could result in mutations and trigger cancer. This prediction has
sadly become reality in the first cancer cases identified among the
handful of “successes” in gene therapy at the end of 2002. These
patients were exposed to transgenic DNA similar in construction to
those in GM foods.
The technology by which many GMOs
are made is inherently dangerous, also because it often involves the
creation, directly or indirectly, of super-viruses, which, unlike
most natural viruses, are capable of crossing species barriers.
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