Letter: GM arrogance

Sir: It is arrogant of Professor Pridham (letter, 25 June) to presume that those who have concerns about current policy on GM foods are ignorant of the basic science involved.

There is a difference in kind, not just degree, between use of genetically modified organisms within the highly controlled environment of the laboratory for production of recombinant proteins for medicinal and other use and the release into the environment of genetically modified food crops.

Professor Pridham appears to show a doubtful grasp of the science in his assertion that current practice is no more than a natural extension of all that has gone before - a common claim of GM food proponents. I invite the professor to propose the natural mechanisms by which even the most expert selective breeding could induce transfer of a functional gene inhibiting ice crystal formation from an Arctic fish to a plant species.

The process of facilitating gene transfer between species involves embedding of the desired gene within an artificial DNA construct designed to integrate itself into the genome of a host organism. This renders it realistic, not alarmist, to warn about the danger of "species hopping" by modified genes.

Demands for extraordinary reassurances are justified by the extraordinary potential for spread of any organism cultivated in the open. There is evidence of failure to control spread of GM seed from carefully controlled experimental plots; what chance is there of confining spread when the Eddie Grundies of the farming world get their hands on these crops?

KENNETH CAMPBELL

Kettering, Northamptonshire