"DNA Contamination Feared," declared the Washington Post last fall. "Gene-altered DNA may be 'polluting' corn," warned USA Today. Both papers–as well as many other media outlets around the world–were reporting the results of a scientific study published in the prestigious journal Nature. Anti-biotech activists at Greenpeace, Friends of the Earth, and the Union of Concerned Scientists immediately seized on the results to press for a ban on planting and exporting genetically enhanced crops. It now appears that that study's conclusions are completely bogus.
Last fall, Ignacio Chapela and David Quist, two researchers from the University of California, claimed that they had tested a number of samples of local "creole" corn taken from farms located in remote areas of Oaxaca, Mexico. They claimed that by using a very sensitive genetic test called inverse polymerase chain reaction (IPCR), they had found the cauliflower mosaic virus 35S (CaMV35S) promoter in the local varieties of corn. (Such local, noncommercial varieties are sometimes known as "landraces.")
CaMV35S is regularly incorporated in many genetically enhanced crops as a way to get the genes added by biotechnologists (transgenes), such as those for insect resistance, to express themselves. The Berkeley researchers suggested that perhaps native Mexican corn varieties had by chance crossbred with genetically enhanced varieties brought in from the United States, despite a Mexican government ban since 1998 on planting bioengineered corn. Perhaps some Mexican farmers had used corn imported for feed as seed instead, they speculated. "The probability is high that diversity is going to be crowded out by these genetic bullies," asserted Chapela in USA Today.
Although Ignacio Chapela is an assistant professor of microbiology at Berkeley, he is not exactly the model of a dispassionate scientist. For example, in 1999 Chapela signed the "World Scientists' Statement Calling for a Moratorium on GM Crops and Ban on Patents," organized by a variety of anti-biotech activist groups. The Statement called for a five-year ban on planting all genetically enhanced crops and a permanent ban on patenting crops, cell lines, and genes. Chapela is also a board member of the activist group Pesticide Action Network of North America, which is also campaigning against plant biotechnology. In other words, Chapela is a well-known anti-biotech activist.
Two questions arise from the Nature study: Is it true? And does it matter?
Earlier this year, the Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico (the research center that launched the Green Revolution) checked its extensive collections of corn and could find no evidence that local varieties and bioengineered varieties had crossbred. At the time CIMMYT released the results of its analysis, its researchers had asked Chapela for samples of his materials so that they could check them, but he had not sent them.
Now a comprehensive review prepared for the editors of the journal Transgenic Research, which will be published in its February 2002 issue, finds that "no credible scientific evidence is presented in the [Chapela and Quist] paper to support claims made by the authors that gene flow between transgenic maize and traditional maize landraces has taken place." The review finds, "It is most likely that the report by Quist and Chapela is a testimony to technical failure and artifacts which are common with PCR and IPCR." Typically IPCR false positives occur because samples can be easily contaminated with the material being tested for.
Furthermore, according to the review, "most frustrating" is that Chapela and Quist did not use other, more reliable, techniques to determine the presence of the transgenes.
The Transgenic Review article also soundly condemns Nature for rushing to publish this flawed study. "What is very surprising, however, is that a manuscript with so many fundamental flaws was published in a scientific journal that normally has very stringent criteria for accepting manuscripts for publication….It is very disappointing that the editors of Nature did not insist on a level of scientific evidence that should have been easily accessible if the interpretations were true. Consequently, no evidence is presented to justify any of the conclusions presented in the paper."
So are genetically enhanced varieties "genetic bullies" that threaten corn biodiversity as Chapela claims? Not at all.
"There is no scientific basis for believing that out-crossing from biotech crops could endanger maize biodiversity," said Luis Herrera-Estrella in a statement issued in December. Herrera-Estrella is a noted plant scientist and director of the Center for Research and Advanced Studies in Irapuato, Mexico. "Gene flow between commercial and native varieties is a natural process that has been occurring for many decades. Nor is there reason to believe that these genes will become fixed into landraces unless farmers select them for their increased productivity," added Herrera-Estrella. "In the end, that would result in improving the native varieties."
What's the bottom line? Chapela's "research" is probably not a case of witting fraud, just another activist "scientist" finding what he desperately wanted to find. But the serious question is, Why did the editors of one of the world's leading scientific journals choose to abet him in his anti-biotech campaign by publishing his sloppy work? One has to wonder if perhaps their scientific judgments are being clouded by their ideological concerns. The least the editors of Nature can do now is withdraw the paper formally with apologies to the scientific community.