National Post
Friday, June 28, 2002

Canola study raises fears of 'gene flow': Contamination threat

by Margaret Munro

Pollen from canola travels much farther than previously believed, raising new concerns about "gene flow" from genetically modified (GM) crops and the purity of canola seed produced by Canadian farmers. In a study published in the journal Science today, scientists found pollen -- and genes -- from modified canola were carried up to three kilometres by the wind and insects before fertilizing other plants. The study, conducted in Australia, is said to be the first published study that looks at gene flow on large, commercial canola fields. Scientists say the same thing is sure to be happening on the Canadian prairies, where 60% of the canola grown has been genetically modified with transgenes, borrowed from microbes, animals or other plants. "The study underlines a clear risk," says a report in Science. "Once transgenes are introduced they can't be completely controlled."

"This study confirms that pollen can move a long distance and that zero contamination or cross-fertilization is going to be very hard to achieve," says Dr. Linda Hall, of Alberta Agriculture, who studies gene flow associated with GM crops and has reviewed the Australian study. There is much to be learned from the "unique" experiment, says Dr. Hall, stressing the need to learn how to better contain and control the transgene engineered into the next generation of GM crops. Some plants -- "plant factories" as she describes them -- are being designed to be given "novel" transgenes so they can produce industrial oils and medicines. Canadian studies of gene flow and cross-contamination have been much smaller scale and suggested that pollen from GM crops did not travel far.

The Canadian Food Inspection Agency, which approves hundreds of field trials for new GM crops each year, has long maintained that buffer zones of 200 to 300 metres provide "reproductive isolation" of experimental canola crops. Dr. Hall says the results of the new study "are cause to question our existing buffer zones" that are used by researchers testing new genetically modified crops, and by farmers growing canola to produce seed for resale, which must meet purity standards. With insects and the wind capable of carrying pollen several kilometres, she says "a low level of contamination will probably exist in all canola seed grown in Canada."

"This paper shows us zero [contamination] is not achievable in canola," says Dr. Hall. The Australian researchers tested more than 48 million individual plants for their study, which took advantage of a "natural experiment" conducted when modified canola plants, made resistant to certain herbicides through a process known as mutagenesis, were grown commercially in Australia for the first time in 2000. Strictly speaking, the canola tested in the Australian study was not genetically engineered. The products of mutagenesis are not considered to be GM, but the pollen travels the same way in both types of plants.