It will give fresh impetus to groups that have been arguing that genetically modified food and crops require more rigorous testing before they are supplied without labelling to the public. British companies have begun producing foods made with genetically engineered soya imported from the US, and the European Commission approved the use of maize containing a gene providing resistance to antibiotics. However, they have not had to pass tests as rigorous as those applied, for example, to a new pharmaceutical drug being introduced to the market. Foods made with them will also not be labelled because the crop harvesters said it would be too expensive to separate the genetically modified and normal strains.
The new results, by a team at the University of Cologne in Germany, emerged from an experiment in which mice were fed with food containing a virus known as M13 which normally affects bacteria. In subsequent tests, the researchers, led by Walter Dorfler, discovered short sections of the virus's DNA - enough to constitute a gene - in the spleen, liver and white blood cells of the mice.
Such "genetic crossover" has frequently been observed between bacteria cells, but is not expected between bacterial viruses and animal cells.
"They weren't hard to find," Professor Dorfler says in today's New Scientist. "In some cases as much as one cell in a thousand had viral DNA." He added that the DNA did not usually stay inside the cells more than about 18 hours before it was removed, though he suspects that occasionally some might remain. This could form the basis for evolution if some cells retain outside DNA.
But in the case of genetically engineered maize, made by Ciba-Geigy, such DNA incorporation could have unpredictable effects. The maize, intended as an animal foodstuff, contains a gene conferring resistance to ampicillin, an antibiotic. Some scientists fear that the gene could pass to bacteria, creating a "superbug" with enhanced immunity.
The environmental group Greenpeace said Britain should ban the maize. Ciba-Geigy had no comment last night.Reuse content