Scientists discover tomato is ancestor of potato

Scientists have made a surprising discovery revealing that an ancient genetic union approximately 9 million years ago gave rise to the potato, which is now the world's third-largest staple crop. Remarkably, the tomato has been identified as the maternal ancestor of the potato.

The study was conducted by a research team from the Agricultural Genomics Institute in Shenzhen under the Chinese Academy of Agricultural Sciences (AGIS-CAAS), alongside a researcher from Lanzhou University, in collaboration with scientists from Canada and the U.K. 

The cover of the article "Ancient Hybridization Underlies Tuberization and Radiation of the Potato Lineage" published in the journal Cell. 

Their findings show that the potato originated from an ancient hybridization event between the tomato plant and a potato-like species about 9 million years ago. This genetic fusion also led to the development of a novel organ: the tuber.

Published in the latest issue of the journal Cell, these findings offer a groundbreaking theoretical framework for the genetic breeding of potatoes.

Potatoes, the world’s most important tuber crop, are native to South America. Valued for their high nutritional content and remarkable adaptability, they have since spread worldwide.

               AGIS-CAAS Academician Huang Sanwen (Front) is the lead author of the study published in Cell. 

Huang Sanwen, the study’s lead author, explained that the origin of potatoes had long been a scientific mystery. Although modern potato plants closely resemble a potato-like species called Etuberosum, which lacks tubers, phylogenetic analysis reveals that potatoes are actually more closely related to tomatoes.

To solve this mystery, the research team analyzed 101 genomes and 349 resequenced samples from cultivated potatoes and their 56 wild potato species— essentially conducting a comprehensive DNA paternity test for all potatoes.

Non-tuber-bearing and tuber-bearing species of the potato plant. Courtesy of Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences (AGIS-CAAS)

They discovered that all potatoes examined carried stable, balanced genetic contributions from both Etuberosum and the tomato plant, leading them to conclude that potatoes are hybrid offspring of these two species.

To confirm this hypothesis, the team assessed the divergence times of the three species. Their results showed that Etuberosum and tomato began diverging around 14 million years ago, and approximately 5 million years later, they hybridized. This event gave rise to the earliest tuber-bearing potato plants around 9 million years ago.

“The tomato served as the maternal parent of the potato, while Etuberosum was the paternal parent,” Huang stated.

An illustration depicting the evolutionary timeline of the potato lineage. It shows the hybridization event between tomato and Etuberosum, leading to the formation of the potato, followed by its explosive diversification in high alpine meadows.