Modifying Maize

How the accidental finding of genetically modified corn in the highlands of Mexico set off a twenty-year battle over scientific methods, academic freedom, Indigenous rights, environmental law and international trade. Part one of two.

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Modifying Maize


Aldo Gonzalez is an Indigenous rights and maize activist with the Union of Organizations of the Sierra Juarez of Oaxaca (UNOSJO)

Margarito Hernandez Sebastian has been farming in Oaxaca’s Sierra Juarez for more than 30 years

David Quist was formerly with the Arctic University of Norway, now runs Hrímnir ramen in Oslo

Ignacio Chapela is a microbial ecologist and mycologist at the University of Berkeley California, where he now has tenure.

Nick Kaplinsky is an Associate Professor of Biology at Swarthmore College in Pennsylvania, where he runs the Kaplinsky lab.


AFP, “Confirma EU maize contaminado con transgenico en Mexico” El Universal. November 29, 2001

AFP. “Mexique: Des scientifiques denoncent l’existence de mais contamine.”Le Monde. December 2, 2001

Aragón Cuevas, F. “MAÍCES NATIVOS NATIVOS DE OAXACA”. CIBIOGEM Report. December 6, 2011 

Becker, Elizabeth. “U.S. Corn Subsidies Said to Damage Mexico”. New York Times August 27, 2003

Bernstein, Steven.  “Liberal Environmentalism and Global Environmental Governance”, Global Environmental Politics, 2,3 (2002): 12.

Boehmer Christiansen,  Sonja. “The Precautionary Principle in Germany: Enabling Government”, in O’Riordan, T. and J. Cameron eds. Interpreting the Precautionary Principle, 1994.

Brief Communications, Nature, 416 (April 2002): 600-602.

Carroll, Sean B. “Tracking the Ancestry of Corn Back 9,000 Years.” New York Times. May 24, 2010

Coale Kristi. Seeds of Secrecy”, Mother Jones. June 2002

Commission for Environmental Cooperation Secretariat Report. Maize and Biodiversity: The Effects of Transgenic Maize in Mexico. 2004 ISBN 2-923358-00-7

Corespondence, Nature, 417, 27 (June 2002): 897-898.

Dalton, R. Berkeley dispute festers over biotech deal. Nature 399, 5 (1999).

Earth Summit Opening Plenary, Part 1. C-Span. June 3, 1992.

Forson, P.W. and Counihan, C. Taking Food Public: Redefining Foodways in a Changing World. Routledge, 2013

For controversial biology researcher Ignacio Chapela, the long and winding road ends with tenure at Berkeley”. Press Release, UCBerkeley News. May 21, 2005

Ford Runge, C and Jackson, Lee Ann. “Labeling, Trade and Genetically Modified Organisms (GMOs): A Proposed Solution”. Working Paper WP99-4, Center for International Food and Agricultural Policy, University of Minnesota. November 1999

Foyer, Jean  and  Bonneuil,  Christophe. Mexican Biosafety as a “performance of seriousness”: Distancing and the Transgenic “contamination” of Mexican Maize. 2014. Ffhalshs-01092208f

Garcia Ruiz, Mayra Teresa.  Knapp,  Aaron N. & Garcia-Ruiz Hernan (2018) Profile of genetically modified plants authorized in Mexico, GM Crops & Food, 9:3, 152-168, DOI: 10.1080/21645698.2018.1507601

Gerdes, Justin. “Killing the Messenger.” Mother Jones, July 9, 2002.

Gorz, Andre.  “Reform and Revolution” Socialist Register 5 (1968): 111-143.

GRAIN. “Mexico: The dangers of industrial corn and its processed edible products”. March 20, 2018

Harkinson,  Josh. “Yes, It’s True: GMOs Contaminate Mexican Corn.” Mother Jones, February 24, 2009.

 Hanson, J. Precautionary Principle: Current Understandings in Law and Society, Encyclopedia of the Anthropocene, 2018.

KARI/ CIMMYT IRMA Project. “Insect Resistant Maize for Africa (IRMA) Project Annual Report 2002.” IRMA Project Document No. 10. P 74

Maitre, Michelle. “Supporters urge tenure for outspoken professor” Easy Bay Times. Dec 10, 2004

Mercer, K.L., Wainwright, J., 2008. Gene flow from transgenic maize to landraces in Mexico: an analysis. Agriculture, Ecosystems and Environment 123, 109–115.

Monbiot, George. “The Fake Persuaders”. The Guardian.  May 14, 2002.

Nájar, Alberto. “Polémica por maíz transgénico en México.” BBC World. October 23, 2009

Noble, Ivan. “Mexican study raises GM concern” BBC News. November 28, 2001

O’Leary, Matthew. “Maize: From Mexico to the world” CIMMYT, International Maize and Wheat Improvement Center. May 20, 2016

O’Riordan, T. and J. Cameron eds. Interpreting the Precautionary Principle, 1994.

 O'Riordan, T and A Jordan "Precautionary Principle in Contemporary Environmental Politics" Environmental Values 4, 3 (1995): 191-212.

Percival,  Robert V. Who's Afraid of the Precautionary Principle?, Pace Envtl. L. Rev. 21 (2006).

Philipkoski, Kristen, “Professor, Biotech Butt Heads”. Wired, December 13, 2003.

Pineyro-Nelson, A. et al. 2009. Transgenes in Mexican maize: molecular evidence and methodological considerations for GMO detection in landrace populations. Molecular Ecology, 18(4), pp.750-761.

Platoni, Kara. “Kernels of Truth.” East Bay Express. May 29,  2002

 Quist, David. and Ignacio H. Chapela. Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico, Nature, 414 (November 2001):541-543.

Ramírez Cuevas, Jesús De maíz su carne y su corazón”. La Jornada del campo. No. 121. December 21, 2017

Recino, Adrián. Popul Vul: The Book of the People. Translated by Delia Goetz and Sylvanus Griswold Morley. L.A. Plantin Press, 1954

Rodríguez-Arévalo, I., Mattana, E., García, L. et al. Conserving seeds of useful wild plants in Mexico: main issues and recommendations. Genet Resour Crop Evol 64, 1141–1190 (2017).

Shetterly, Caitlin. “Modified: GMOs and the Threat to Our Food, Our Land, Our Future” September 2016. Penguin.

Stacey, Jocelyn.  “Preventive Justice, the Precautionary Principle and the Rule of Law”, in Tamara Tulich et al, (eds) Regulating Preventive Justice (New York: Routledge, 2016): 6.

Suppan, Steve. “Do No Harm: NAFTA, non-regulation of GMOS and Mexican agriculture.” Institute for Agriculture and Trade Policy, November 6, 2017.

Sweeney, Stuart & Steigerwald, Douglas & Davenport, Frank & Eakin, Hallie. (2013). Mexican Maize Production: Evolving Organizational and Spatial Structures since 1980. Applied Geography. 39. 78–92. 10.1016/j.apgeog.2012.12.005.

“The Precautionary Principle in Canada” Environmental Law Centre, June 2010.

Turrent Fernández, Antonio et al. El maíz transgénico en México (en 15 píldoras) versión Oaxaca. 2013(p56)

Vargas-Parada, L. GM Maize splits Mexico. Nature 511, 16–17 (2014) doi:10.1038/511016a

Vidal, John. “Mexico's GM corn shocks scientists” The Guardian. November 30, 2001

Wade, Lizzie. “Mexico’s new science minister is a plant biologist who opposes transgenic crops” Science Magazine. October 4, 2018

Wagner, Holly (2005-08-08). "Genetically modified maize not found in southern Mexico". Ohio State University Research News.

Wainwright, Joel and Mercer, Kristin. The dilemma of decontamination/ A Gramscian analysis of the Mexican transgenic maize dispute. Geoforum 40 (2009): 354.

Wingspread Statement on the Precautionary Principle, SEHN, 1998.Wise, Timothy. “High Risks, Few Rewards For Mexico with Monsanto's Maize” Al Jazeera. May 27, 2014

Zuidema, Teake. “Drought is crippling small farmers in Mexico—with consequences for everyone else Quartz. December 14, 2019


This episode was produced by Polly Leger and James L. Frederick. Editing by Acey Rowe and Gordon Katic. James Rhatigan was our research assistant. Fact checking by Aurora Tejeida

Our theme song and original music is by our composer, Mike Barber. Dakota Koop is our graphic designer. Our production manager is David Tobiasz, and executive producers are Gordon Katic and Sam Fenn.

Thank you to: Ana de Ita Rubio, Santiago Muñoz  and Daniela Moreno from the Maizajo tortilla shop, Silvia Ribeiro from ETC Group, Topher Routh at Berkeley Advanced Media Studio for recording assistance,  and Martin Gepp, Benji Shieh and Alexander Kim for help voicing. Katrina Hiibackof the University of Toronto, Professor Dave Ng of UBC and Dr. Sophie Comyn helped us untangle plant genetics.

Fernando Ortiz Monasterio’s account of his meeting with Ignacio Chapela comes from an interview with Caitlin Shetterly, in her 2016 book, “Modified.”

This episode was funded in part by the Social Science and Humanities Research Council of Canada. This is part of wider project challenging ideas in liberal environmental thought. The project was advised by Jessica Dempsey at the University of British Columbia, and Rosemary Collard from Simon Fraser University.

Cited is produced out of the Centre of Ethics at the University of Toronto, which is on the traditional land of Mississaugas of the Credit, the Anishnabeg, the Chippewa, the Haudenosaunee and the Wendat Peoples. Cited is also produced out of the Michael Smith Laboratories at the University of British Columbia -- that’s on the unceded territories of the Musqueam, Squamish, and Tsleil-Waututh Nations.