Letter: Modified facts

WE DEPLORE your story about our review of the safety of plant viral inserts ("Super-viruses threat to farms", 21 March). It was typical of your biased scare-mongering over GM foods and crops. You state that, according to our "damning" report (it was not damning), "genetically engineered crops, altered to be resistant to common plant viruses, risk creating new strains of `superviruses' which could wipe out entire farms".

In fact, our conclusions on page 54 stated that "... [genetic] selection of mutants able to overcome transgene-mediated resistance has not been demonstrated. Although the probability of this hazard cannot be estimated, the appearance of resistance-breaking mutants is unlikely to pose additional harm to untransformed [wild-type] plants when compared to the parental virus."

Moreover, we concluded that the probability of recombination between a virus-derived resistance gene and an infecting RNA virus is much lower than the probability of natural recombination events between two or more viral genomes in multiply-infected plants in the wild. We could go on.

PROF MICHAEL WILSON DR HUGH BARKER

DR TEIFION JONES

DR STUART A MacFARLANE

DR MICHAEL A MAYO DR DAVID J ROBINSON DR SIMON SANTA CRUZ

Scottish Crop Research Institute Dundee

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