Nature backs away from Mexico transgenic study

Prestigious scientific journal Nature has been forced to back away from its support of a controversial study claiming that transgenic DNA sequences from GM corn contaminated native maize in Mexico.

The study by David Quist and Ignacio Chapela, of the University of California, Berkeley, published in Nature in November last year, reignited debate about genetically modified crops. Mexico banned the planting of GM corn in 1998 to protect the genetic diversity of its native maize varieties.

But severe criticism of the paper by other scientists prompted the journal to request further information from the authors under threat of retracting the paper.

In its April 4 online edition, Nature published two criticisms of the work and a rebuttal from the authors, including new data in support of their work. In addition, a statement by editor Philip Campbell withdrew support for the original paper.

The statement read in part:

"In light of these discussions and the diverse advice received, Nature has concluded that the evidence available is not sufficient to justify the publication of the original paper. As the authors nevertheless wish to stand by the available evidence for their conclusions, we feel it best simply to make these circumstances clear, to publish the criticisms, the authors' response and new data, and to allow our readers to judge the science for themselves."

The original study made claims that the transgenic constructs had not only introgressed into traditional maize varieties, but reassorted and inserted in a "diversity of genomic contexts." Critics of the paper pointed out that not only were there a lot of technical errors in the paper, but that the reassortment and random insertion of the transgenic DNA was unprecedented.

Dr TJ Higgins, assistant chief of CSIRO Plant Industry, expressed concerns that the Quist and Chapela paper was published without adequate review.

"You have to be extraordinarily careful about the review process," he said, explaining that a great deal of trust between authors and reviewers is required.

Higgins suggested that the work might have been published before it was fully complete.

"It is hard to believe that they had done all of the controls," he said, adding that the authors had allegedly refused to give any of their material to other scientists for confirmation.

Higgins said that such situations adversely affected public confidence in science. "It confuses the public, who are already confused and polarised by misinformation," he said.