Scientists have discovered that the potato evolved from a tomato ancestor nearly 9 million years ago through a hybridisation event. The research, published in the journal Cell, analysed 450 genomes from cultivated potatoes and 56 wild species, revealing that wild tomatoes in the Andes crossed with a plant called Etuberosum, mixing their genetic material to form an entirely new lineage.
“Tomato is the mother and Etuberosum is the father,” said Professor Sanwen Huang of the Agricultural Genomics Institute in Shenzhen, China, who led the research. “But this wasn’t obvious at first.” Above ground, potato plants look almost identical to Etuberosum, but Etuberosum lacks the starchy tubers that make potatoes a global food staple.
The team identified two key genes: SP6A from tomato and IT1 from Etuberosum. Neither gene alone is sufficient for tuber formation, but when combined, they interact to trigger the development of tubers. “The study is groundbreaking,” said Professor James Mallet of Harvard University. “It shows how a hybridisation event can spark the emergence of a new organ – and even lead to a new lineage with many species.”
The potato’s tubers store energy, helping the plant survive winter or drought and reproduce without seeds or pollinators. This adaptation allowed potatoes to thrive in the high-altitude habitats of the rising Andes, leading to an explosion in diversity. Humans later domesticated wild species, selecting those with large, edible tubers.
The potato left the Andes on Spanish ships in the 16th century and became a staple across Europe and the world. Researchers are now exploring artificial hybridisation to create new varieties, including a project to help potatoes reproduce by seeds and to introduce tuber-producing genes into tomatoes.
