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TITLE:  Letter D – Interview with David Quist
SOURCE: Seedling, GRAIN, Spain
DATE:   April 2003

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Letter D

David Quist was one of the authors of the first study to report the
contamination of one of the centres of genetic diversity with genetically modified
(GM) crops. The paper erupted into what has become known as the 'Mexican maize
scandal'. Here GRAIN talks to Quist about the aftermath of the volcano and
the implications for farmers, scientists and consumers.

GRAIN: What is the story behind the study that ignited such controversy
around the world?

David Quist: The story began in a small laboratory in Oaxaca in the
highlands of Mexico. My professor Ignacio Chapela had been serving as a scientific
director for four indigenous communities which had banded together to manage
their natural resources. I had been working with them on another project, but
would also help them with technical workshops. These were all indigenous-run
projects with the ideas and initiatives coming from the communities
themselves. One question that came up for them was whether GM crops were an issue they
should be concerned about. We said that Mexico had a moratorium on planting
transgenic crops at the time, so it should not be something they needed to
worry about immediately, but it might be something they would want to consider
down the line as the situation might change.

The groups wanted to learn more, so on one of my trips there, I brought some
transgenic corn with me and we ran a workshop on testing for transgenic DNA.
We needed a transgenic-negative control, and what better place than the
highlands of Oaxaca, the birthplace of maize? We worked out a sampling protocol,
did the DNA extraction and ran the analysis. The day before the workshop I
ran a test sample and couldn't believe the results - some of the native corn
tested positive. We had also taken a sample from the local food agency, which
also tested highly positive. These food agencies distribute food in every
village throughout the country, and while the maize is supposed to be used only
for consumption, there is no label on it saying, "Do not plant this". This
means that in every village in Mexico has these point sources of potential

We went back to the lab, did some new sampling, and more widespread and
stringent analysis, the results of which became the Nature paper. [1] But first
we felt we had to go to the Mexican government to let them know what we had
found, even if it might compromise our ability to publish the work. In the
Nature paper, we made two main statements. The first was simply that genes from
the transgenic corn had migrated into native populations. For this we used a
technique called PCR, which is widely used to amplify the DNA of interest into
sufficient quantities to identify and analyse it. It is the standard tool
for GMO identification used by regulatory agencies throughout the world for
accepting or rejecting shipments of GM-free grain. The second statement was more
exploratory and used a new technique called inverse PCR that allows us to
look more specifically at where in the plant's genome the transgenic DNA is
located. To our surprise we found it in a diversity of places within the native
maize genome. There could be various explanations of why this might be, one
of which is that the transgenes had become reinserted through recombination.
[2] We felt there was sufficient evidence to suggest that this explanation
might be true, so we published it. And that is part of what science is:
proposing novel explanations from observed patterns in data, from which further work
is done to substantiate or refute the initial findings. We knew this was a
bit novel, a bit "out there", because there was no previous science behind it
and no-one was doing it. At least there was nothing in the peer-reviewed
literature, but it wouldn't surprise me if companies have done this kind of work
without publishing it, if they did not like what they saw. People responded by
saying that there is no evidence that this kind of gene shuffling is what is
going on, but no-one has looked, no-one has asked these questions before. We
wanted, and expected, a strong reaction, but not in the way it came.

GRAIN:A year and a half on from the publication of your paper in Nature,
what is your perspective on why there was such a strong reaction to this paper?

DQ: The first wave of response was to trivialise the first statement that we
made, which simply said that the transgenes were present in the native
landraces. The proponents of biotech were saying 'we know that commercial
varieties cross with local varieties all the time - no big deal.' What created a
bigger response was what we were exploring in looking at what those genes were
doing once they got there. We were going against the propaganda of the industry
which says that this technology is precise, this technology is stable. We
were suggesting that it is unstable, which infuriated the pro-biotech
community. Another reason was that the timing of these findings was really bad for the
industry - our findings were biting up against the debates on the moratoria
in Europe, Mexico and Brazil. It was a huge PR disaster. In addition, the
industry was in a downturn economically. When you look at where the strongest
reaction was coming from, there were very significant links to Berkeley and the
Berkeley-Novartis deal that was signed five years ago. [4] At that time a
number of groups were raising concerns about what it meant for academic
freedom, student education, and so on. Dr Chapela was a leading opponent of the
signing of the agreement within the college and I was also involved in a vocal
group opposing the deal called Students for Responsible Research. I don't think
it is insignificant that the most vocal detractors of our paper came from
the camp that supported the Novartis deal back in 1998.

 From Iowa to Oaxaca: Easy passage for the Bt gene

Maize is the most important crop in Mexico. About 1.5 million hectares of
the maize grown consists of hybrid varieties (developed mainly by transnational
companies), 0.9 million hectares are open pollinated varieties (developed by
the public sector and small companies) and the remaining 5.5 million
hectares are planted to local land races. Some 68% of the maize grown in Mexico is
used directly for human consumption. Maize is also an extremely important crop
to the US, the world's largest maize producer and exporter. In 2000, Mexico
was second only to Japan as a market for US maize, absorbing 11% of US
exports. Some 24% of total corn consumption in Mexico now comes from the US. Since
1996, US maize exports to Mexico have increased as exports to Europe have
decreased, owing to Europe's rejection of GM maize. Of the 5-6 million tons of
maize that were imported to Mexico in 2000, 30%-40% was transgenic, but was
not segregated or labelled. That same year Mexico had exactly the same amount
of domestic maize rotting away, unused. The maize that comes into Mexico gets
distributed through welfare food systems around the country. It is subsidised
from beginning to end by US taxpayer dollars. Incredible amounts of money go
into the production of this grain that receives subsidised water, soil,
machinery and oil; is subsidised in international markets; and subsidised again
in Mexico through distribution. It just floods the country. When you talk to a
farmer in Oaxaca, they say, "It costs six pesos to grow seed; I can buy it
for four." The farmer is paying out of his or her pocket to plant his or her
own seed. Small wonder that transgenic maize is so widespread in the fields of

Sources: "Dr Ignacio Chapela on Controversy, Corn and What's Really at Stake
in Mexico", Global Pesticide Campaigner, August 2002; Chantal Carpentier and
Hans Herrmann, Maize and Biodiversity: The Effects of Transgenic Maize in
Mexico: Issues Summary, CEC,

What has been the effect of all this on the work you are doing, and has
there been follow-up work?

 DQ: The contamination of local maize varieties was a completely unexpected
discovery. I wasn't working on maize when it happened, and I wasn't looking
for this when it happened. My training is in mycology. However, since this
study I have switched to asking questions about gene flow and how genes move in
the environment, both horizontally and vertically [5] and I am doing some
follow up work in that area. Transgene ecology is a fledgling field. There are a
couple of other institute, such as the Norwegian Institute of Gene Ecology
[6] and the New Zealand Institute of Gene Ecology, [7] which are doing some
great work, but I don't think they are working on agricultural issues to any
great extent. And unfortunately, when a particular branch of science becomes
politicised, it becomes a hot potato that scares others away from working in
the field. In the case of maize, who is asking the questions about the
implications for farmers, human health, and global food systems? In Mexico, those
questions have still to be answered. To its credit, the government is doing
follow up work to look at the scale of transgene contamination around the
country, but it has yet to employ any kind of strategy to try and manage it or
ascertain its significance.

 On a different tack, a number of civil society groups, spearheaded by
Greenpeace, [8] applied in April 2002 to the North American Free Trade Agreement's
Commission for Environmental Cooperation (CEC) to investigate the issue.
CEC's mandate is to look at the environmental impacts of the NAFTA agreement or
environmental issues that will impact the NAFTA agreement, and accepted the
challenge. But I'm very sceptical that, given the composition of the committee
appointed to investigate the issue and also the nature of the CEC's mandate,
that the investigation will have the political fortitude to state anything
other than 'there is no evidence that this poses any harm, therefore we should
continue importing maize from the US'. However, there is no way they could
make a statement like that from a scientific, ecological point of view without
conducting rigorous science, which I do not think they are not doing, at
least at this point. They are just going to come up with the usual fallback
position that absence of evidence is evidence of absence, which is scientifically
fallacious. The Mexican government did a follow-up study in response to your
findings. What kind of research did they do and how was their research

In the first round, samples were taken from 22 communities in Pueblo in
Mexico, 15 of which tested positive using the same PCR technique that we used.
Since then, they have done a much more expansive study in terms of sampling and
techniques. The government submitted its results to Nature, but its paper
was rejected in October 2002. [9] Two reviewers rejected the paper for opposite
reasons. One said that the findings were "obvious" (having already been
reported before in Nature), while the other said they were "so unexpected as to
not be believable." To have two reviewers making such drastically different
interpretations of the same data is interesting - there is obviously a story
behind that.

GRAIN:The Mexican Government established a moratorium on planting GM corn in
1998, so how did the transgenic maize get there?

 DQ: In our local setting, we suggested two possible sources of
contamination - very local sources (such as the food agency maize) or that it was wind
blown from the industrial maize planted in the valley about 60 miles away in
Puerta Vallerta. The first explanation seems the most likely: farmers have
admitted that they have planted food agency maize. The food agency maize we
tested was highly transgenic - its positive signal was as strong as our transgenic
positive. There are also a number of agricultural research stations that
have been doing field tests of GM corn in open field plots before and after the
moratorium came into effect.

GRAIN:What are the implications of your work for farmers in Mexico, and
small farmers in particular? What are the biggest threats to them?

 DQ: One is all the unknowns - the ecological significance, the effects on
human health and genetic diversity, for instance. Those kinds of studies
should have been done already, but weren't. We just don't know. The second is the
unresolved questions related to liability and intellectual property issues.
If Monsanto goes into the highlands of Oaxaca and finds its genes in a
farmer's field, who shoulders the liability – the farmer or the corporation? In the
case of Percy Schmeiser, the liability fell with the farmer (see p 10). But
according to the 'polluter pays' principle, if the company has compromised the
farmer's ability to produce for certain markets, then the company should be
liable. The third major threat to farmers is the loss of markets owing to the
pollution of their maize crops.

GRAIN:What about the wider implications?

 DQ: I am concerned about the impact on science. It is unfortunate that the
debate became so politicised and the real issue was discredited because of
some disagreements over the interpretation of the I-PCR data. While there was a
lot of noise made about the paper, there has been what I call "scientific
silence" over it: no-one is doing the follow up work to refute or support our
findings and no-one is asking what the implications of them are. People have
reacted defensively: because they don't see what they expect to see, they call
our results "erroneous". This kind of approach is a disservice to science.
What we are seeing more and more is that the science of substantiating facts
is overriding science as a process, which is all about questioning and
re-examining our assumptions, in order to lead us to a better understanding of
reality. The way that the debates are framed and the inability of corporate
science to re-examine its paradigms are compromising good science. What message
does this send to other scientists who make the 'wrong' findings or ask the
'wrong questions', ie those that go against the science of the corporate agenda?

The events that have occurred also raise a lot of questions about the true
objectivity of the peer-review process in scientific reporting. Science
recently published a fairy tale story about the success of Bt cotton in India, [10]
despite the fact that Bt cotton is failing miserably all over India.
Nature's handling of our paper suggests that it was under pressure from the industry
camp. As the heat built up, the journal did not handle things very well and
made a lot of people angry, on both sides. Two of the three referees said
that they did not challenge the main conclusions of our paper, but suggested
writing a correction to part of it. Why didn't the editor make this clear, point
out that there were some issues of contention over certain aspects of our
findings, and put out calls for more work on the subject? Why the need for a
disavowal? And why were most people left with the impression that the paper had
been retracted, when it was not? A hallmark of good science is in asking
exploratory questions - just as we were doing. We weren't out of step with that,
but the response we received was out of step with the way that normal
scientific discourse should happen to advance scientific knowledge. Situations like
this call into question whether these journals can continue to be looked to
as a reliable source of objective science.

Since 1998, David Quist has been a graduate student in the PhD Programme in
Environmental Science, Policy and Management at the University of California,
Berkeley, California. A mycologist by training (someone who studies fungus),
he made the discovery about the contamination of maize varieties in Mexico
quite by chance. Since the study that was published in Nature, his work has
become more focused on transgene ecology - ie how genes move about in the
environment. David Quist can be contacted by email at

[1] David Quist and Ignacio Chapela, "Transgenic DNA introgressed into
traditional maize landraces in Oaxaca, Mexico", Nature Vol. 414, pp541 - 543
(2001) Chapela_Research.htm

[2] ie the transgenic material had become fragmented and scattered
throughout the genome

[3] For a fuller insight into what became publicly known as 'the maize
scandal', go to

[4] Under this agreement, Novartis provided $25 million to the Department of
Plant and Microbial Biology (a third of the department's income) in return
for first right to negotiate licenses on roughly a third of the department's
discoveries (including research funded by public money) and 2 out of 5 votes
on the committee that determines how the department's money is spent.

[5] Vertical gene flow is the way in which genes are passed on from parent
to offspring through cross-pollination. Horizontal gene flow is the direct
uptake and incorporation of foreign DNA into cells



[8] Greenpeace press release, "Mexican Groups, Greenpeace Launch NAFTA
Appeal To Force Action Against Genetic Contamination", April 24, 2002, 2002/04242002text

[9] Food First Press Release, "Nature Refuses to Publish Mexican Government
Report Confirming Contamination of the Mexican Maize Genome by GMOs", October
24, 2002,

[10] Matin Qaim and David Zilberman, "Yield Effects of Genetically Modified
Crops in Developing Countries", Science Vol. 299: 900

Reference for this article: Matt Mellen, 2003, Interview with David Quist,
Seedling, April 2003, GRAIN

Copyright notice: GRAIN publications may be reproduced, translated and
disseminated freely. We ask only that the original source be acknowledged and that
a copy of your reprint be sent to GRAIN.

Website link:

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