AgBioWorld Mexican Maize Resource Library
Available online at:
About The Issue
In the November 29, 2001 issue of the journal Nature, University of
California at Berkeley graduate student David Quist and mycologist Ignacio
Chapela reported evidence that genes from genetically-engineered maize
(corn) varieties had crossed into landraces of maize in southern Mexico
and had become permanently established (introgressed) in the genome of the
maize landraces they tested, and that the transgenes were unstable and
moving around in the maize genome. In subsequent news coverage of their
paper, Quist and Chapela also suggested that such introgression threatens
the genetic diversity of landraces in Mesoamerica, the center of origin
and diversity of maize.
Within days, numerous independent scientists identified flaws in the Quist
and Chapela report and notified the Nature editors of the errors. The
editors of the journal Transgenic Research even published a critique,
explaining the methodological flaws in the Nature article. "What is very
surprising," wrote Paul Christou, director of the molecular biotechnology
unit at the John Innes Centre in Norwich, UK, on behalf of the Transgenic
Research editors, "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."
Because opponents of agricultural biotechnology had begun using the
Mexican Maize case as an example of genetic engineering gone wild, the
defense of Quist and Chapela became something of a cause c╚l╦bre. None of
the critical reviews of the Quist and Chapela report disputed the
possibility that transgenes may have crossed into landraces. Nevertheless,
those scientists have been attacked by individuals and environmental
organizations that have a stake in scaring the public about genetic
engineering. They even accused the scientists who have questioned the
Quist and Chapela results of committing "academic intimidation" and of
conducting "a highly unethical mud-slinging campaign."
In response, scientists organized through AgBioWorld Foundation crafted a
"Joint Statement in Support of Scientific Discourse in Mexican GM Maize
Scandal," defending the freedom of scientists to rigorously examine the
results and methodology of reported research. The statement
(http://www.agbioworld.org/jointstatement.html) affirms that "relentless
double-checking and independent third party evaluations are the
cornerstones of the scientific process," and further, "This is in fact how
science corrects mistakes and ever more closely approximates truth and
The real question is one of academic integrity. Since the dogged and
relentless pursuit of truth is the ultimate goal of science, should Quist
and Chapela have been allowed to publish such obviously flawed findings?
Furthermore, if Quist and Chapela were so eager to overlook the
shortcomings of their research, perhaps observers ought to be somewhat
more skeptical of their other claims about the relevance of those
In the end, the editors of Nature ultimately admitted in the April 4, 2002
issue of the journal that the Quist and Chapela paper was riddled with
methodological errors and should never have been published. Quist and
Chapela have subsequently presented data that further supports the
presence of transgenes in maize landraces-a point that has not been
disputed. Ultimately, science still must resolve whether or not the flow
of transgenes into maize landraces will have significant negative impacts
on either maize genetic diversity or on the broader environment, but the
answer is likely to be no.
Here, AgBioWorld presents a brief library of resource documents of
relevance to the Mexican maize issue. Readers are asked to review the
materials and judge for themselves.
Science Journal Articles and Letters
Quist D and Chapela IH. 2001. Transgenic DNA introgressed into traditional
maize landraces in Oaxaca, Mexico. Nature 414: 541-543.
Christou P. 2002. No Credible Evidence is Presented to Support Claims that
Transgenic DNA was Introgressed into Traditional Maize Landraces in
Oaxaca, Mexico. Transgenic Research 11: iii-v.
Martinez-Soriano JPR and Leal-Klevezas DS. 2000. Transgenic Maize in
Mexico: No Need for Concern. Science 287: 1399.
Martinez-Soriano JPR, Bailey AM, Lara-Reyna J, and Leal-Klevezas DS. 2002.
Transgenes in Mexican Maize. Nature Biotechnology 20: 19.
Apel, Andrew, "Mexican Maize Fiasco Erupts," Biotech Reporter (January
Bailey, Ron, "Environmentalist Biofraud? A new report challenges research
published in the respected journal, Nature." Reason (February 12, 2002).
Available at: http://reason.com/rb/rb021202.shtml
Conko, Gregory and C.S. Prakash, Report of transgenes in Mexican corn
called into question. ISB News Report (March 2002): 3-5.
Hodgson, John, "Maize uncertainties create political fallout," Nature
Biotechnology Vol. 20, No. 2 (February 2002): 106-107.
Hodgson, John, "Doubts linger over Mexican corn analysis," Nature
Biotechnology Vol. 20, No. 1 (January 2002): 3-4.
Mann, Charles C., "Has GM corn 'Invaded' Mexico?" Science 295: 1617-1618.
Manning, Anita, "Gene-altered DNA may be `polluting' corn," USA Today
(November 29, 2001)
Scientists Say Mexican Biodiversity Is Safe: Concerns About
Cross-Pollination Unfounded. AgBioWorld Foundation Press Release (December
Mexican Maize Not Under Threat: Biologically diverse gene flow is natural
and expected, not "contamination". AgBioWorld Foundation Press Release
(March 1, 2002).
El Ma╠z Mexicano No EstĚ Siendo Amenazado
El flujo de genes biol█gicamente diversos es natural y esperado, no es
"contaminaci█n" (11 de marzo de 2002 )
Joint Statement in Support of Scientific Discourse in Mexican GM Maize
Mexican Maize Documents from the International Maize and Wheat Improvement
Center (CIMMYT) in El Batan, Mexico
http://www.cimmyt.org/whatiscimmyt/transgenic_index.htm (in English and
"Proceedings of a Forum-Gene Flow Among Maize Landraces, Improved Maize
Varieties, and Teosinte: Implications for Transgenic Maize," Sponsored by
the Mexican National Institute of Forestry, Agriculture, and Livestock
Research (INIFAP), the Mexican National Agricultural Biosafety Committee
(CNBA), and the International Maize and Wheat Improvement Center (CIMMYT)
Website of Dr. Juan Pablo R. Mart╠nez-Soriano of the Center for Research
and Advanced Studies (CINVESTAV) in Irapuato, Mexico
http://jpms1.ira.cinvestav.mx (in English and Spanish).
Loutte D and Smale M. 2000. Farmer's seed selection practices and
traditional maize varieties in Cuzalapa, Mexico. Euphytica 113: 25-41.