Sir

One reason for the unsatisfactory state of GM food regulation1 is the assumption, stated in the FAO/WHO biotechnology and food safety report3 and adopted by UK regulators, that genetic engineering does not differ from conventional selective breeding. Hence, Trewavas and Leaver2 conclude that GM food should not be subject to more rigorous testing than novel non-GM food.

I believe this assumption is erroneous. Genetic engineering enables exotic genes from viruses and bacteria and other non-food species to be introduced into food crops. These genes are combined in novel constructs, often with viral promoters to make genes overexpress continuously. The constructs are inserted into genomes by transformation techniques that cannot control where the genes go, resulting in a range of unpredictable positional effects and rearrangements. I would prefer to have a moratorium on environmental releases of GM material until safety issues have been more adequately and openly addressed.