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POLLEN from genetically modified maize appears to have reached remote
mountainsides in the wilds of Mexico. David Quist and Ignacio Chapela from the
University of California at Berkeley found that the stray pollen had crossed
with wild maize growing on mountainsides of the Sierra Norte de Oaxaca in
southern Mexico. They suspect it came from field demonstrations of GM maize
about 100 kilometres away, before a moratorium on planting was introduced in
1998. DNA from the ancient maize, the ancestor of modern cultivated varieties,
contained gene fragments which can only have come from GM maize (Nature,
vol 414, p 543). The researchers warn that long-distance drift of GM pollen
might threaten the purity of ancient crop varieties even if they grow in remote
locations.