Page 263 - Environment: The Science Behind the Stories

CentrAl CAse stUdy

transgenic Maize in southern Mexico?

UNITED STATES
Atlantic
Ocean
“Worrying about starving future generations
won’t feed them. Food biotechnology will.”

MEXICO —Advertising campaign of the Monsanto Company
“Industrial agriculture has . . . destroyed
diverse sources of food, and it has stolen food
from other species . . . using huge quantities
CENTRAL of fossil fuels and water and toxic chemicals
AMERICA
Oaxaca in the process.”
— Vandana shiva, director of the Research
Pacific Foundation for science, technology, and
Ocean Natural Resource Policy, India
SOUTH
AMERICA

Corn is a staple of the world’s food supply. We can trace its organism and transfer them into the DNA of another. The aim
ancestry back 9000 years, when people in the highland val- is to improve crop performance and feed the world’s hungry,
leys of southern Mexico first domesticated that region’s wild but many people worry that transgenes, the genes engineered
maize plants. The corn we eat today arose from some of the and moved into these transgenic plants, may have unintended
many varieties that evolved from the selective crop breeding consequences. One concern is that transgenic crops might
conducted by this region’s people. crossbreed with local landraces and thereby “contaminate” the
Today southern Mexico remains a center of biodiversity for genetic makeup of native crops.
maize, with many locally adapted domesticated varieties, called Such contamination was exactly what University of California
landraces, growing in the rich, well-watered soil. Preserving at Berkeley professor Ignacio Chapela and his postdoctoral
such traditional varieties of crops in their ancestral homelands associate David Quist discovered while testing Mexican maize.
helps to secure the future of our food supply, scientists say. They had ventured to the southern Mexican state of Oaxaca
These varieties serve as reservoirs of genetic diversity that we (pronounced “wha-HA-ca”) and found what they argued were
may need to draw upon to sustain or advance our agriculture. traces of DNA from genetically engineered corn in the genes of
For this reason, food experts around the world expressed native maize plants. They alerted Mexican government scientists,
alarm in 2001 when scientists conducting genetic tests of and these scientists independently examined Oaxacan maize
Mexican maize landraces announced that they had turned and obtained similar results. Quist and Chapela published their
up DNA (p. 47) that matched genes from genetically modified research findings in the scientific journal Nature in 2001.
(GM) corn. GM corn was widely grown in the United States, but Activists opposed to GM food trumpeted the news and
Mexico had banned its cultivation in 1998. urged a ban on imports of transgenic crops into developing
Genetically modified foods are foods derived from nations from producer countries such as the United States.
genetically modified organisms (GMOs), organisms that are The agrobiotech industry defended the safety of its crops and
genetically engineered. Genetic engineering is any process questioned the validity of the research—as did some of Quist
whereby scientists directly manipulate an organism’s genetic and Chapela’s peers. Responding to criticisms from research-
material in the laboratory by adding, deleting, or changing seg- ers, Nature took the unprecedented step of stating that Quist
ments of its DNA. and Chapela’s paper should not have been published—a
Corn is one of many crops that researchers have geneti- decision that ignited a firestorm of controversy (see The Science
cally engineered to express desirable traits such as large size, behind The STory, pp. 284).–285
fast growth, and resistance to insect pests. To genetically Subsequent research by Mexican government scien-
262 engineer crops, scientists extract genes from the DNA of one tists reported that in 15 localities, 3–60% of maize contained

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