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WonderNatural gene transfer fact

Cultivated sweet potatoes carry DNA that passed into them naturally, long ago, from a soil bacterium called Agrobacterium, and some of those bacterial genes are still active. No laboratory was involved: the crop is a naturally genetically modified plant.

Sweet potato

BiologyEvolutionFoodScience

The story behind the card

Agrobacterium is known for inserting part of its own DNA into plants, making them produce nutrients for it; since the 1980s, genetic engineers have used the same trick to add genes to crops. In 2015 a team led by Tina Kyndt and Godelieve Gheysen of Ghent University, working with the International Potato Center, reported bacterial DNA in the sweet potato genome. One insertion, containing four bacterial genes, was present in all 291 cultivated varieties they tested but not in the plant's close wild relatives. That pattern suggests early farmers may have unknowingly favoured plants carrying it, perhaps for a trait it affected, although which trait, if any, is still unknown. The case is often mentioned in debates about genetically modified food.

Türkçe oku
Yetiştirilen tatlı patateslerde, çok eskiden Agrobacterium adlı bir toprak bakterisinden doğal yolla geçmiş DNA bulunur ve bu bakteri genlerinden bazıları hâlâ çalışır. İşin içinde hiçbir laboratuvar yoktur: tatlı patates, doğanın kendi eliyle genetiği değiştirilmiş bir bitkidir.

Agrobacterium, kendi DNA'sının bir parçasını bitkilere sokup onlara kendisi için besin ürettirmesiyle bilinir. Genetik mühendisler de 1980'lerden beri aynı yöntemle bitkilere gen aktarıyor. 2015'te Gent Üniversitesi'nden Tina Kyndt ile Godelieve Gheysen'in yürüttüğü ve Uluslararası Patates Merkezi'nin de katıldığı bir çalışma, tatlı patates genomunda bakteri DNA'sı buldu. Dört bakteri geni içeren bir parça, incelenen 291 kültür çeşidinin hepsinde vardı; bitkinin yakın yabani akrabalarında ise yoktu. Bu tablo, ilk çiftçilerin bu parçayı taşıyan bitkileri farkında olmadan seçmiş olabileceğini düşündürüyor. Parçanın hangi özelliği etkilediği, gerçekten bir etkisi olup olmadığı hâlâ bilinmiyor. Bu örnek, genetiği değiştirilmiş gıdalarla ilgili tartışmalarda sık sık anılır.

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