Oops. The journal Nature says it shouldn’t have published a report about genetically engineered corn leaking exotic genes into traditional races of the crop in Mexico.
In the Nov. 29, 2001, edition of the prestigious journal, David Quist and Ignacio H. Chapela of the University of California, Berkeley reported that genes artificially inserted into commercial crops wended their way into native maize as well (SN: 12/1/01, p. 342: Transgenes migrate into old races of maize). Mexico lies in the evolutionary cradle of corn, and the government doesn’t allow farmers to plant bioengineered corn there. The November paper fueled concerns that such supposed sanctuaries for natural genetic diversity are feeling the impact of bioengineering. However on April 4, the journal took the unusual step of admitting “that the evidence available is not sufficient to justify the publication of the original paper.”
Nature posted its comments online, with two critiques of the paper plus additional research results from its authors.
Spokesmen from each group of critics say they accept the basic idea that transgenes have entered traditional maize races. “I think you would be hard-pressed to find people–including me–to bet against that,” says Matthew Metz of the University of Washington in Seattle, a coauthor of the first critique. Nicholas Kaplinsky of the University of California, Berkeley says that assuming the new experiments were properly controlled, the original researchers’ new results strengthen their claim that transgenes entered the maize.
The criticisms of the original paper, however, focus on just what those transgenes are doing once they get into the maize. The 2001 paper argued that over generations, some transgenes break up and the pieces jump to various locations throughout the genomes of native maize plants. Certain genetic elements do jump around, says Kaplinsky, but no one has reported transgenes behaving in such an unstable and unpredictable way.
Both sets of critics contend that Quist and Chapela had made methodological mistakes, among them misidentifying some of the DNA sequences from the maize and misinterpreting experimental artifacts as data about locations of transgenes in the maize genomes.
“If these results had been real, it would have been huge,” Kaplinsky says.
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In their reply in Nature, Quist and Chapela acknowledge some of the errors. However, the two scientists say that their new evidence confirms their original detection of transgenic DNA in southern Mexico maize.