April 19, 2002

scientists react to reports of GM pollution.

The report by Mexican government scientists, presented at the Convention on Biological Diversity in The Hague, suggested that genes from USA GM maize had crossed the Mexican border, polluting non-GM maize grown there.

The Mexican scientists looked for genetic traces of the cabbage mosaic virus, which is used to carry modified DNA sequences into plants. However, this virus is commonly found naturally in unmodified plants.

Mark Tester, Senior Lecturer in plant sciences, University of Cambridge, said:

“Assuming that the government scientists have used the same technique as Chapella and Quist, they are using a fearsomely sensitive technique which is very prone to giving false positive results. I question why they chose to look for a gene sequence that is so common in the environment when a much more specific method could easily have been used. For me, the jury is still out.”

Professor Anthony Trewavas, Professor of Plant Biochemistry, University of Edinburgh, said:

“Such claims could cause serious knock on effects for the more vulnerable of the world. We have to increase cereal production by at least 50% in the next 25 years and this will have to be on the same area of land. The shenanigans over GM threaten the livelihood and survival of those in the developing world who are most in need of crops with pest resistance and other GM properties.”

Dr Peter Raven, Director of the Missouri Botanical Garden, said:

“Related species of plants regularly cross-breed. It is a feature of their evolution, and not one that arises because of the use of GM technologies to improve crop characteristics.”

Luis Herrera-Estrella, Director of the Center for Research and Advanced Studies in Irapuato, Mexico, said:

“There is no scientific basis for believing that out-crossing from biotech crops could endanger maize biodiversity. Gene flow between commercial and native varieties is a natural process that has been occurring for many decades.”

Notes to editors · A comprehensive review of Quist and Chapela’s original research into the Mexican maize contamination was published in the journal Transgenic Research in February this year, which said, “No credible scientific evidence is presented in the paper to support claims made by the authors that gene flow between transgenic maize and traditional maize landraces has taken place.” · The standard method for checking if contamination has occurred in a crop is to deliberately create a cross-breed, and then compare the DNA of the two. Crucially, this test does not appear to have been done. · The gene amplification technique used by the Mexican scientists was widely believed to be not the best for the job. It is apparently notorious for producing ‘false positive’ results. Useful links: ‘Worst ever’ GM Crop Invasion by Charles Clover, Daily Telegraph.