Rob Edwards's article on GM omitted crucial information which explains why Professor Gilles-Eric Seralini's studies have been rejected by every competent authority concerned with food safety throughout Europe and the US (Why has study saying GM could kill been ignored, News, September 1).

Harlan, which markets the Sprague Dawley rodents used by Seralini, state that 755-80% of their inbred line spontaneously (and thus at random), develop tumours within a two-year period - something Seralini omits to mention.

The OECD provides recommendations on rodent numbers to be used for two-year feeding trials so that statistical significance of any treatment can be established. The control numbers used were too small for any significant change to be detected. The kinds and numbers of tumours formed in Seralini's experimental treatments fell within the historical norm for this rodent line and with a proper number of controls, statistical analysis would have indicated there was no effect. Thus the claim that the genetically engineered corn component of the diet or the herbicide caused the tumours was insupportable.

There are many hundreds of life-cycle feeding experiments using GM crops using numerous animal species, including farm animals. When properly performed, no effect has been reproducibly established.

The benefits of GM crops to farmers, wildlife and to farm emissions have been established many times. Crops with direct benefits to consumers are well on the way.

The longer aim of these GM opponents is for organic farming - but they omit to tell the public that in Germany in 2011, 54 people died and thousands received permanent physiological injury from eating organic produce. No-one has died or been injured from eating GM food.

Professor Tony Trewavas

Scientific Alliance Scotland