Brussels
A CONTROVERSIAL form of genetically engineered maize grown in the US, and
approved for import by the European Commission, is continuing to cause trouble
in Europe. Last week, Luxembourg became the second EU member to ban the
maize.
The maize, produced by the Swiss-based firm Ciba, carries a gene for a
bacterial insecticide called Bt, and another for resistance to a herbicide. But
the controversy surrounds a third gene, for resistance to a widely used
beta-lactam antibiotic, ampicillin, introduced as a genetic 鈥渕arker鈥� to reveal
which plants had taken up the other genes. Many scientists fear that the
antibiotic resistance gene could spread to bacteria in the guts of livestock fed
the maize, and then to bacteria infecting humans.
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Last December, the Commission approved the maize on the advice of three
scientific committees. Almost immediately, Austria launched a legal challenge to
the decision (This Week, 4 January, p 8). Austria鈥檚 import ban took effect last
week, and can go on for three months while the country tries to reverse the
Commission鈥檚 decision. Luxembourg raised the stakes by announcing its own import
ban last week.
Denmark is 鈥渨atching the situation closely鈥�, according to an official, as is
Sweden. France says it will allow maize imported from the US鈥攁ny of which
could contain a small quantity of the genetically engineered version鈥攐nly
if it is labelled as genetically modified.
When the Commission approved the maize, it did not immediately release the
reports from its committees. But the Scientific Committee for Food鈥檚 report has
now been seen by New 杏吧原创鈥攁nd will do little to end the
controversy.
The maize contains a DNA sequence that triggers cells to make up to 600
copies of the antibiotic resistance gene. This would increase the chance of the
gene being passed to other bacteria.
The food committee鈥檚 report says there is little cause for alarm, as it is
unlikely that DNA would survive intact in an animal鈥檚 gut to be picked up by
bacteria. Any bacterium carrying hundreds of copies of the gene would waste
energy making vast quantities of the enzyme that disables ampicillin. This means
it 鈥渨ould not have a competitive advantage and therefore would not spread鈥�, says
the report.
But Tony Atkinson of the drugs company Duramed, a member of
Britain鈥檚 Advisory Committee on Novel Foods and Processes, says there is 鈥減lenty
of evidence鈥� that DNA can survive in an animal鈥檚 gut. He also claims that the
widespread use of beta-lactam antibiotics on livestock 鈥渨ould provide a major
competitive advantage鈥� to bacteria carrying the resistance genes.