13 June 2002

SPECIAL INVESTIGATION: THE GREAT MEXICAN MAIZE SCANDAL

Fred Pearce
New Scientist, 15 June 2002

For environmentalists, the work was proof of the dangers of genetic modification. Transgenes had spread to traditional maize varieties grown in Mexico. Then the journal Nature disowned the research paper, prompting claims that it had given in to a campaign orchestrated by the biotech industry. But why were the authors' strongest critics their own colleagues? Here, we reveal the extraordinary goings-on behind the headlines.

THE saga began in September 2001. The Mexican environment ministry announced that DNA from genetically modified maize had been found in native varieties grown on small farms.

The results were, not surprisingly seized upon by campaigners opposed to GM crops. And in November, they were given more ammunition when the findings were published in the prestigious journal Nature. Then, this April, things took a confusing turn. In an unprecedented move, Nature declared that it regretted publishing the paper, and ran two letters that claimed the research was fatally flawed.

The turnaround has generated even more coverage than the original finding. It is the first time Nature has ever disowned a paper in defiance of its authors and referees. Some suspect foul play, claiming that representatives of the biotechnology industry orchestrated a campaign of letters and petitions criticising the original paper. But the paper's critics at the University of California, Berkeley where the key protagonists in this saga have all worked, may not have needed any outside encouragement.

The paper's authors - graduate student David Quist, an environmental scientist, and his professor, Mexican plant biologist Ignacio Chapela, were already hate figures on the Berkeley campus. In 1998, they had campaigned unsuccessfully to prevent the university striking an extraordinary alliance with the Swiss biotech company Novartis. The deal, signed amid student protests and piethrowing, gave Novartis the rights to cherrypick the best plant research for development in exchange for up to $50 million. But while the protesters see it as compromising academic freedom, many in the Department of Plant and Microbial Biology owe their jobs to the deal with what's now called Syngenta.

Two years later, on the night of 11 October 2000, environmental activists destroyed GM maize being grown at Berkeley by students of Mike Freeling, who is a member of the department. The group told a local paper that they had tested the maize to make sure it was genetically modified.

The angry researchers feared an inside job, and initially pointed the finger at Quist. "Just prior to the vandalism, Quist had requested primers from some of the corn geneticists in my department that might be used to identify transgenics in the field," Steven Lindow, a senior professor in the department, told New Scientist. His colleagues "became concerned, and became even more suspicious after the vandalism", he says.

A fortnight after the crops were destroyed, Lindow spoke to Quist's professor, Chapela, about the allegations. Today Lindow says he quickly accepted that Quist was innocent. But Quist says that the allegation festers on, and "has led to irrevocable damage to my academic credibility".

At the time of the field trashing, Quist was in the Mexican state of Oaxaca, collecting samples of maize from farmers' gelds. When the research based on these samples hit the headlines a year later, it was potentially far more damaging to the careers of biotechnologists at Berkeley than heavy boots in a field at midnight.

Quist and Chapela first used PCR, the standard DNA amplification technique, to detect the DNA sequences engineered into Bt maize grown in the US. "This is a standard method of detection used by regulatory agencies in Europe and elsewhere," says Quist. It can generate false positives, he agrees. But the pair say that results from their controls show "beyond reasonable doubt" that the sequences are present in a few samples of the native strains from remote regions in Mexico. The pair then used a related technique called inverse PCR to discover the precise position of the transgenic sequences. This seemed to show that the added DNA had fragmented and scattered throughout the maize genome˜the finding that triggered an outcry among scientists.

The authors are still fuelling the dispute. "It suggests that transgenic DNA can move around the genome with a range of unpredictable effects, from disruption of normal functions to modification of expressed products that become toxic agents to the generation of new strains of bacteria and viruses," Quist told New Scientist this month.

The two critical letters published by Nature in April attacked this second finding. And Quist and Chapela conceded that there were flaws, when, in a letter that Nature published at the same time, they said: "We acknowledge that our critics' assertion of the misidentifying of sequences . . . is valid."

In less fraught circumstances, a partial retraction of the original paper might have been enough to satisfy both sides. But Nature demanded the authors retract the whole paper, and they refused. So the journal ran its own unprecedented disavowal, in the same issue as the critical letters. This asserted that "in the light of diverse advice received . .. the evidence available is not sufficient to justify the publication of the original paper".

Quist and Chapela point out that, whatever technical failings might have emerged after publication, their paper had been approved by three anonymous referees. It must have had some merit. And when it and the letters of complaint were submitted to three more referees, two of them specifically noted that none of the comments disproved the conclusion that transgenic corn is growing in Mexico.

"The main finding is not controversial or really being challenged," says Quist. "Neither of the two letters published in Nature, purportedly showing fatal flaws in our paper, ever questioned our main discovery."

Nature has not responded directly to New Scientist's questions about why it would not accept the authors' partial retraction. "Nature has never said that the paper's conclusions are wrong," is all editor Philip Campbell will say. "We have said that they are not convincing on the basis of the evidence that we have published." He denies that a campaign against Quist and Chapela influenced his decision to demand a retraction of their paper˜and to disown it when they refused.

But a campaign there certainly was. Demands that the paper be retracted appeared on Internet biotech forums the day it was published, and continued with mounting vehemence. Yet two of the first, most persistent and apparently scientifically qualified complainants on the Net, "Mary Murphy" and "Andura Smetacek", appear not to be real people. A British anti-GM campaigner, Jonathan Matthews of the Norfolk Genetic Information Network, claims to have tracked their electronic personas to the offices and computer equipment of the Bivings Group in Washington DC, a PR company that has Monsanto as one of its clients. Bivings initially denied everything but has since admitted that one of the emails came from a Bivings' employee or client.

But what has raised most eyebrows is the identity of the scientists whose two letters attacking the paper appeared in Nature. "The antagonists signing the letters are all connected directly with [Berkeley's] local political scandal," says Chapela.

One was co-written by Freeling and Nick Kaplinsky who is also a senior figure at the same department at Berkeley. The other was by Matthew Metz, a former Berkeley microbiologist who was a vocal supporter of the Novartis alliance, and Johannes Futterer, a young Swiss researcher whose boss, Wilhelm Gruissem, was at Berkeley four years ago and was widely regarded as "the man who brought Novartis to Berkeley".

Quist and Chapela believe the animosities created by the furore over the deal, and inflamed by the crop trashing, must be an element in the row over their paper. Kaplinsky denies this. "This issue is strictly about science. Quist and Chapela published bad science and should have done the honourable thing˜retract their paper and apologise."

But Kaplinsky doesn't stop there. "Since they seem incapable of admitting their mistakes, they are raising non-scientific issues like the Novartis agreement with our department, vendettas, global conspiracies. Anything so they can avoid talking about the fact that they published artefactual data and then misinterpreted it."

Campbell says he wasn't aware of the allegations surrounding the crop trashing incident when he accepted the letters. But he says it would not have influenced his decision to publish. Neither Nature nor Campbell are poodles of the biotech industry. Campbell himself wrote a hostile editorial about the Berkeley-Novartis deal. But Quist still insists that it was political pressure that brought about the journal's actions.

Whoever is right, the row reveals an alarming breakdown in scientific discourse. In the aftermath of the affair, Campbell wrote that it must have been Murphy's law that ensured the journal's embarrassing climb-down "was in relation to one of the most hotly debated technologies of our time". Others see it as more than an accident. They fear that the affair has put the system of peer review to the test, and found it wanting.

The spectre of unseen actors manipulating events is particularly worrying. In its disavowal, Nature asked its readers to make up their own minds about the science behind the row. But it failed to alert them to the private rows behind the public letters. Nor did it reveal the identities and affiliations of the five referees who broadly supported the original paper, or the sixth who appears to have persuaded Nature to make a retraction.

Also out of sight are the individuals behind "Mary Murphy" and "Andura Smetacek", not to mention the people who trashed Freeling's field two years ago. Strange what dark shadows are thrown up by the harsh glare of publicity.