- NEW YORK (Reuters
Health) - Despite Mexico's 3-year-old moratorium on the use of genetically
altered corn, scientists have detected genetically modified DNA in wild
maize in the mountains of the state of Oaxaca.
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- Whether the modified DNA came from seeds planted before
the moratorium or from growers flouting the law is unknown, but the spread
of altered genes in the birthplace of domesticated corn could have "very
serious consequences," one of the investigators told Reuters Health.
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- "We show that the areas of diversification--the
genetic bank account of diversity--for this crop, corn, is compromised,"
Dr. Ignacio H. Chapela at the University of California, Berkeley, said
in an interview.
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- Chapela explained that Oaxaca is the region where corn
was domesticated. Even today most of the diversity of corn is found there,
he said.
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- Each year, according to Chapela, breeders go to Oaxaca
to look for beneficial genes in wild corn that could be transferred into
commercial crops. For instance, wild corn might contain genes that make
it resistant to pests or better able to survive environmental conditions,
such as drought.
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- The spread of modified DNA into wild maize may represent
a "cashing in on the bank account" of diversity, Chapela noted.
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- Referring to genes that have been added to genetically
modified varieties of commercial corn, Chapela said, "We were not
supposed to see these moving around in the environment."
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- Chapela and a colleague at Berkeley, Dr. David Quist,
sampled several varieties of maize native to Oaxaca to see whether they
contained material from two strains of genetically modified corn used in
the US.
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- Five of the seven types of maize they sampled tested
positive for genetically modified material, Chapela and Quist report in
the November 29th issue of the journal Nature. In contrast, tests on maize
from Peru and a sample saved from the 1971 growing season in Oaxaca were
negative.
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- It is uncertain whether the genetically modified material
made its way into wild maize because farmers in Oaxaca are illegally planting
genetically modified corn or whether the modified DNA has been passed down
from crops planted before the moratorium, the researchers point out.
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- Chapela said that he would like to find out whether the
presence of these so-called transgenic genes is increasing, decreasing
or staying the same. Its spread should be studied to "see if we can
reverse it," according to the Berkeley scientist.
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- He noted that corn is one of the most important crops
in the world. The spread of genetically modified material could be wider,
he added, since the same principle applies to other crops such as rice
and wheat.
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- SOURCE: Nature 2001;414:541-543.
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