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© iStockphotoThe findings highlight the failure of efforts to shield Mexico from unauthorized GM corn, says on researcher
Genes from genetically-engineered corn have been found in traditional crop strains in Mexico, according to a new study likely to reignite a bitter controversy over biotech maize.

The study by scientists from Mexico, the United States and the Netherlands, appears in the latest issue of Molecular Ecology, and backs a 2001 study that sparked a row over the safety of genetically modified (GM) crops.

Green activists say GM crops are a potential hazard, arguing that their genes could spread to related plants through cross-pollination.

Their campaign has helped drive bans on GM crops in some countries, including Mexico itself, the ancestral home of maize, as corn is also called.

Contentious study

In the 2001 study, published in the journal Nature, researchers reported finding trans-genes in samples of corn taken from the Sierra Juarez region of Oaxaca.

This study was blasted for technical inaccuracy and choice of samples. Nature later distanced itself from the paper, saying the evidence had not been strong enough to warrant publication.

A further study, carried out in 2005 by a different team, was unable to replicate the results.

But new research now says the original study was right.

A team led by Elena Alvarez-Buylla of the National Autonomous University in Mexico City looked at nearly 2000 samples from 100 fields in the region from 2001 and 2004, and found that around 1% of the samples had genes that had jumped from GM varieties.

"We confirmed that there was contamination in 2001 and also found contamination in 2004, which means that it either persisted in the local maize that we sampled or that it was reintroduced, which is less likely," says Alvarez-Buylla.

She says the difference between previous studies and her research lay in the samples chosen for gene sequencing and in the molecular technique for decrypting the DNA.

The investigators looked for two specific genes that had escaped from biotech corn, and found them in some fields, but not in others.

Shielding failure

Alvarez-Buylla says the evidence sheds stark light on the failure of efforts to shield Mexico from unauthorised GM corn.

The country imposed a moratorium on the planting of transgenic maize in 1998 in order to protect genetic diversity. It is the home of about 60 traditional domesticated strains, also called landraces, as well as several wild strains.

Transgenic seeds are entering the country, most probably from the United States, and getting mixed with local seeds in trade among small farmers, says Alvarez-Buylla.

"It is very hard to avoid gene flow from transgenic maize to non-transgenic maize in Mexico, even though there has been a moratorium," she says.

"It is really worrying that the government of Mexico has not been efficient enough in biosecurity monitoring," says Alvarez-Buylla, accusing watchdogs of failing to establish rigorous molecular monitoring that was independent of data provided by biotech giants.
Unknown effects

Alvarez-Buylla's team did not explore the impact of the escaped genes on the native corn, on the local environment or human health, nor did it test whether the foreign genes passed on to progeny plants.

GM crops have had genes inserted into them to produce benefits for farmers. For instance, they exude natural toxins that kill off pests, or are resistant to herbicides, enabling a farmer to spray a field once and not kill the crop.

GM producers say there is no evidence of any threat to human health or the environment. The overwhelming view of scientists is that, so far, this is true.


Comment: There is evidence that GM technology is a threat to human health. Read the following articles:

GMO Scandal: The Long Term Effects of Genetically Modified Food in Humans
Lyme & Autism Group Blasts Genetically Modified Foods as Dangerous
Doctors: Avoid Genetically Modified Food and GMOs
Doctors Warn: Avoid Genetically Modified Food
Austrian Government Study Confirms Genetically Modified (GM) Crops Threaten Human Fertility and Health Safety
Potential Health Hazards of Genetically Engineered Foods
Genetically Engineered Crops May Produce Herbicide Inside Our Intestines
GM Files: Horrifying New Disease Contains Identical Material to GM "Food"

In addition there are serious environmental risks of GM Technology:

Germany to ban cultivation of GMO maize: Minister sez: "A Danger to the Environment"
Brown warned of dangers in promoting GM crops
New Study Shows Genetically Engineered Corn Could Pollute Aquatic Ecosystems
'GM Seed Spread' Warning


But suspicions remain strong in many countries, especially Europe, where several governments retain safeguard measures against GM corn despite European Union approval.