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The modern-day potato originated from a hybridization event with tomatoes around 9 million years ago, according to a new study in Cell. This ancient interbreeding between wild tomato plants and potato-like species in South America triggered the formation of the tuber, the underground storage organ that defines potatoes today. Scientists had long been puzzled by the potato’s origins because, while it closely resembles tuberless plants like Etuberosum, genetic studies showed a closer relationship to tomatoes. To solve the mystery, researchers analyzed 450 cultivated potato genomes and 56 wild species. They found all potatoes carry a stable mix of genes from both Etuberosum and tomatoes, confirming a hybrid origin. Though the two parent species split from a common ancestor 14 million years ago and diverged for 5 million years, they managed to interbreed, producing the first potatoes with tubers. The study also identified two key genes behind this trait: SP6A, which controls when tubers form, came from tomatoes, while IT1, which shapes underground stems into tubers, came from Etuberosum. Without both, tubers wouldn’t exist. This evolutionary breakthrough coincided with the rapid rise of the Andes, where tuber-forming plants gained an edge in surviving cold, harsh environments. Tubers also allowed potatoes to reproduce without seeds, helping them spread across diverse habitats—from mountain meadows to lowland grasslands. Over time, this gave rise to a wide variety of potato species. sourceZhang, Zhiyang et al. "Ancient hybridization underlies tuberization and radiation of the potato lineage." (2025) Cell, Volume 0, Issue 0