The Surprising Tomato-Potato Connection: How a 9-Million-Year-Old Hybrid Shaped Our Favourite Spud
For UK Gardeners, Potatoes Are A 9 Million Year Old Versatile, Reliable, And Endlessly Rewarding Staple Crop. Yes 9 Million. But Have You Ever Wondered Where This Beloved Tuber Came From?
Table of Contents
A groundbreaking Chinese genetic study has revealed that potatoes owe their existence to an ancient natural crossbreeding event between wild tomatoes and a potato-like plant in South America around 9 million years ago.
The Mysterious Origins of the Potato
First domesticated in the Andes 7,000–10,000 years ago, potatoes were introduced to Europe by Spanish colonisers in the 1500s. Yet, their wild origins remained a puzzle…until now.
Freshly harvested potatoes
Published in the journal Cell, new research shows that potatoes emerged from a hybridisation between wild tomato plants (Solanum lycopersicum) and a non-tuberous cousin called Etuberosum, found in central Chile. This unlikely pairing led to the evolution of the tuber—the nutrient-storing underground structure that makes potatoes so valuable.
“Our findings show how hybridisation between species can spark entirely new traits, allowing even more species to emerge,” says Sanwen Huang of the Chinese Academy of Agricultural Sciences. “We’ve finally solved the mystery of where potatoes came from.”
Tomato Genes Hidden in Your Spuds
Modern potatoes (Solanum tuberosum) are nearly identical to Etuberosum, except for the tubers. Even more confusingly, genetic analysis shows that potatoes are more closely related to tomatoes than to their closest lookalikes.
To crack this riddle, scientists analysed 450 cultivated potato genomes and 56 wild Etuberosum genomes—the most comprehensive study of wild potato genetics ever conducted.
“Wild potatoes are very difficult to sample, so this dataset is a major breakthrough,” says lead author Zhiyang Zhang.
The results? Every modern potato carries a stable mix of tomato and Etuberosum DNA, confirming an ancient hybridisation event. Further analysis revealed that:
Tomatoes and Etuberosum shared a common ancestor 14 million years ago.
Around 9 million years ago, they crossbred again, producing the first wild potato.
The Genetic Secrets of Tuber Formation
Two key genes control tuber development:
SP6A (from tomatoes) – acts as a master switch, telling the plant when to form tubers.
IT1 (from Etuberosum) – helps underground stems swell into tubers.
Without both genes, no potatoes would exist.
Why Did Potatoes Evolve Tubers?
This evolutionary leap happened during the Miocene epoch, a period of global cooling and drying. In South America, the Andes Mountains were rapidly rising (10–6 million years ago), creating harsher conditions.
“Evolving a tuber gave potatoes a huge survival advantage,” says Huang. “It allowed them to thrive in extreme environments, leading to the incredible diversity we see today.”
A Fun Thought for Gardeners
Next time you enjoy tomato ketchup with your chips, remember—you’re reuniting two long-lost plant relatives! This fascinating history adds a new layer of appreciation for the humble spud. Whether you’re planting earlies, maincrops, or heritage varieties, you’re cultivating a crop with a 9-million-year-old backstory.
Research Source
Title:“The genomes of 240 wild and cultivated potatoes reveal the genetic basis of tuber evolution” Authors: Zhiyang Zhang, Yuxin Jia, Pei Wang, et al. Journal:Cell Publication Date: Sept 2025 DOI:https://www.cell.com/cell/fulltext/S0092-8674(25)00736-6
