Professor Anthony Trewavas: I Yam Convinced GM Food Is Safe

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The sweet potato was the first genetically modified food – 8,000 years ago, writes Professor Anthony Trewavas

The sweet potato (commonly called a yam) is a familiar root vegetable on our supermarket shelves. The swollen root is highly nutritious, low in fat but high in vitamins A, C and fibre. It is easily grown and is eaten by one billion people world-wide. Hardy varieties are necessary for cultivation in the UK and are available from seed merchants. It is unrelated to the potato but it too can be roasted, fried, boiled, chipped and baked and acts as one of the recommended five-a-day. If you, too, have eaten sweet potato you have eaten your first genetically modified (GM) meal.

Some 8,000 years ago a bacterium (Agrobacterium) inserted two of its genes into the original sweet potato DNA, thus producing a GM sweet potato. These genes have been detected in some 300 varieties of yam but are absent in close wild relatives; they are expressed and cause tissues like the root to swell. Domestication was probably based on root size and thus continued propagation of its GM variety. These observations have considerable consequences for those that oppose GM crops.

In one, well-publicised opposition statement it was argued that mixing genetic material from species that cannot breed naturally takes mankind into areas that should be left to God. While this statement is a matter of belief, the occurrence of an entirely natural GM yam surely suggests GM technology is a perfectly legitimate area of intervention for mankind, just as conventional plant breeding is legitimate. It was further claimed that cultivation of GM crops would cause ecological disaster and seriously damage the soil. The current annual world yield (125 million metric tonnes) of the GM yam is grown throughout Africa, Asia, the Americas and Pacific islands. Current growing area is about 12 million hectares. Has the predicted ecological disaster or soil damage followed cultivation? If it has, it is proving very well hidden.

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Featured image: The sweet potato or yam was genetically modified not by Man, but by nature. Picture: Getty