Letter: Engineered crops

Sir: If Jonathan Jones is going to "play God" with our food, he needs to show a lot more ecological and biological wisdom than appears in his article (Comment, 9 June).

Food production must be based on sustainable agriculture if we are to have long-term solutions to our food problems. The most prominent genetically engineered crops about to be released are herbicide-resistant plants that perpetuate the use of toxic chemicals. Monsanto is doubling its production of Round-Up (glyphosate). This takes agriculture in precisely the wrong direction, perpetuating monoculture, destroying biodiversity and increasing rates of soil erosion. Weeds are necessary to maintain insect and hence bird diversity.

What could be useful from biotechnology is genetically stable transgenic plants that are resistant to, for example, disease and drought. But we need to know much more about the consequences of gene transfer before these are released in the field.

Professor Jones claims that transgenic technology is precise. By this he presumably means that specific genes can be transferred from one species to another. However, there is absolutely no precision about where a gene is inserted into a chromosome, and hence about secondary effects concerning metabolites, toxins, allergens and food quality. Furthermore the pathogens (infectious viruses and bacteria) that are used as vectors to carry the gene(s) into a plant are altered so that their host specificity is decreased. These vectors can recombine with wild-type viruses to produce superpathogens that can spread genes and disease indiscriminately .

To call this a precise science when we are so ignorant about these secondary polluting consequences is playing the devil rather than God.