It seemed an ingenious solution to an age-old problem: genetically modify a staple food of developing nations and protect millions from malnutrition. But the story of GM soya has acquired almost mythical status as an example of what happens when scientists tinker with nature.
The idea of creating new crops with improved nutritional value attracted the interest of scientists soon after the first GM crop--a variety of tobacco--was created in 1983. One idea was to insert into the DNA of soya, a staple crop of developing nations, the gene for a brazil nut protein that's rich in amino acids. Alarm bells immediately rang among scientists over the risk from lethal allergic reactions linked to nut proteins, and the idea was dropped. Ten years later, the US biotechnology company Pioneer Hi-Bred resurrected the soya-nut hybrid idea, but tests confirmed the allergy risk among humans. Despite the product being designed as a potential source of poultry feed, Pioneer abandoned the project.
For opponents of GM technology, the allergenic soya bean story highlights the risks that GM hybrids pose to human health. Yet others point out that allergies are a potential risk with any crop--including those bred by conventional methods. The big difference with GM, they argue, is that by altering just a few genes, the risk is easier to assess, while the tighter regulatory control is more likely to spot unexpected side-effects. "There's much concern about allergenicity with kiwi fruit and sesame, both of which were conventionally bred," says Professor Peter Shewry of Rothamsted Research, the leading independent UK crop-research institute. "If anything, the brazil nut story shows how good the regulatory control of GM is."
In fact, the lack of such control over conventionally bred crops has led to just the sort of horror stories usually linked to GM crops. In the early 1970s, a new variety of potato called Lenape was already on the market when tests revealed it contained dangerous levels of toxins called glycoalkaloids. In the 1990s, a naturally bred variety of celery was found to contain very high levels of cancer-causing psoralens and triggered severe dermatitis in some farmers.
There is, however, one potential health risk that is specific to GM crops, and it centres on the 'marker genes' used by researchers to identify which plant cells have been successfully modified. Such genes remain in the plant and are often modified antibiotic-resistance genes. These raise the spectre of the same resistance spreading from plants to bacteria, making infections more difficult to treat. While experts on both sides of the GM debate accept that there is a potential health risk, they also agree there is no evidence of it manifesting itself. The debate now looks set to become irrelevant in any case, as GM companies bring in new markers.
For many, the biggest concern about GM crops centres on the risk of genes escaping from fields, adulterating organic crops or creating 'superweeds' that possess the same resistance to herbicides as the GM crops.
Such concerns have been heightened by studies demonstrating that GM pollen can travel many kilometres from fields, and by an incident in Alberta, Canada, in 2000. …