The potato originated from a cross between the tomato and another plant called the etuberosum, an event that likely occurred around 9 million years ago in what is now South America. An international team concluded that this hybrid origin was behind the formation of the underground structure of the tuber, which contains many nutrients and is widely consumed worldwide, whether fried, boiled, or roasted. The SP6A gene, which acts as a switch telling the plant when to form tubers, came from the tomato, while the IT1 gene, which controls the growth of underground branches that form these swollen roots, came from the etuberosum. Both genes together give rise to potatoes. To unravel the origin of the species, the researchers analyzed 450 genomes of cultivated potatoes and 56 of wild species. All showed equal contributions of genes from the two ancestral plants (Cell, July 31).
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