part of the Tribune's 'MEXICO, MAIZE AND MONSANTO:
Genetic colonialism' feature:
Good enough for U.S., good enough for Mexico?
By Norman C. Ellstrand
Chicago Tribune, April 3, 2005
Despite Mexico's multiyear ban on planting genetically engineered corn, scientists have confirmed that engineered genes have made their way into remote cornfields in Mexico.
For most corn scientists, this discovery wasn't a surprise.
For millenniums, Mexican farmers have managed the genetics of their crops--particularly corn--carefully replanting seed saved from last year's crop, exchanging seed with others and experimenting with new seed when the chance arises. Mexico's native crops may be traditionally grown and managed, but they are genetically sophisticated, far from primitive. Farmers have created a constellation of corn varieties for specific uses, from tortillas to tamales.
Because Mexico imports millions of tons of corn from its NAFTA neighbors, some of that foreign seed might find its way into its cornfields. It is likely that some farmers experimentally planted seed imported from Canada or the United States for human or animal consumption (seed technically known as "grain").
Almost half of that corn seed contains engineered genes.
If a transgenic corn plant in a Mexican field had a chance to flower and cross-pollinate others, then the seed it sired would carry engineered genes. Because it's not unusual for corn pollen to fertilize ears hundreds of feet from a source plant, some transgenes could end up in a neighbor's crop.<BR><BR> But are unintended engineered genes in Mexican corn a big deal?
That question was addressed by a report released last year by the North American Commission for Environmental Cooperation which studies the environmental impacts of NAFTA trade. The report came at the request of Mexican organizations worried about what these unexpected genes might mean for Mexico's environment and health.
Regulatory scientists in the United States, Canada and a few other countries have approved the commercial production of corn with certain transgenes for insect resistance and herbicide resistance. The first variety was approved in the United States a decade ago, without subsequent evidence of environmental or health effects. The fraction of genetically engineered corn has grown to about 40 percent of the U.S. crop.
Not so fast
If it's good enough for the United States, shouldn't it be good enough for Mexico?
Not without Mexican regulatory scrutiny.
The Commission for Environmental Cooperation recommended reducing the likelihood that imported GE corn is planted in Mexico until scientists there can consider the impacts of GE corn in Mexico. This recommendation makes sense for two reasons.
First, regulators in one country don't consider possible impacts of transgenics beyond their borders. I once asked a regulator why a U.S. Department of Agriculture decision document didn't mention that corn naturally hybridizes with its wild relative, teosinte. He said, "Teosinte doesn't grow in the United States, only Mexico. It would be presumptuous to tell the Mexican government what to do." And he is right. Environmental context is important. What is considered a crop in some countries may be a nasty weed elsewhere. Mexican government scientists haven't yet studied the impact of American transgenic corn in the Mexican environment.
Wouldn't Americans be anxious and angry about importing millions of tons of living transgenic seed deregulated in, for example, China, but not by our own regulatory scientists? Clearly, this issue of regulatory sovereignty is critical.
Second, unintended transgene spread could create corn varieties that might not be as benign as the intended varieties.
Corn has been the species of choice for genetic engineers who create plants to produce pharmaceuticals and other industrial chemicals not intended for human consumption. The USDA has approved hundreds of field tests for corn engineered to create such chemicals.
Many of these chemicals wouldn't be harmful if they inadvertently ended up in food. But others would result in adverse health effects, if they occur at high enough levels.
Nonetheless, current U.S. regulations require fairly stringent confinement for so-called pharm crops; thus, if a few pollen grains strayed, siring transgenic seeds that entered the U.S. food supply, the concentration of such compounds would likely be too low to be of consequence or to even be detected.
Because more than 99 percent of American farmers grow hybrid varieties, which are sterile, and thus buy new seed every year, it would be close to impossible for the frequency of such genes (and their unwanted products) to increase in farmers' fields or the U.S. food supply.
It's different for Mexico. Some Mexican farmers use hybrid varieties and do not replant seed. But thousands of others plant saved seed from a previous harvest, often experimenting with seed from their neighbors or taken from a bag of grain distributed for human or animal consumption. Bags of grain for consumption have come increasingly from Mexico's NAFTA partners.
Consider the worst-case scenario.
Assume a tiny fraction of corn seed imported into Mexico contains a transgene that creates a chemical that would have serious health effects in sufficiently high concentrations. Then assume a farmer experimenting with imported seeds plants one with the chemical-producing transgene. Finally, assume that gene confers an advantage to plants that bear it, resulting in more seeds or more pollen.
Then, the conditions are right for the gene to evolve, increasing in frequency, undetected, generation by generation. The chemical also increases in concentration in the food supply until it eventually has serious effects on the health of those eat it.
Although this scenario is unlikely, each separate step has already happened. For example, both the USDA and the Environmental Protection Agency have reported compliance violations in the United States involving seed- and pollen-mediated escape of pharmaceutical-producing corn genes. Luckily, the violations were caught in time, and crop products were destroyed.
The limited planting of pharm corn (a couple of hundred acres) at this time makes international leakage extremely unlikely. But the popularity of pharm crops and the hazard posed by the "worst-case scenario" make clear that now is the time for Mexico to start managing and monitoring the inflow of corn transgenes, as the Commission for Environmental Cooperation suggests.
Managing and monitoring
Gene flow could be managed by treating seeds in some way that prevents germination. Monitoring could be facilitated by requiring that transgenic seed be genetically marked, say, with a seed color trait.
Some have criticized the commission's report as flawed and unscientific.
Yet its scientific basis is sound. Agricultural biotechnology has potential for great benefits. But like any new technology, with potential benefits come potential risks. Like other modern technologies, from electrification to the automobile, the wise use of science maximizes benefits while minimizing risks.
Norman C. Ellstrand is director of the Biotechnology Impacts Center at the University of California, Riverside, and author of "Dangerous Liaisons? When Cultivated Plants Mate with Their Wild Relatives."
Norman Ellstrand - Good enough for U.S., good enough for Mexico?
part of the Tribune's 'MEXICO, MAIZE AND MONSANTO: