It’s a Potato! 

Potatoes are one of the world’s most important foods, a staple in the diet of billions of people. 

The evolutionary history of the world’s third most important staple crop, however, has long been incomplete. 

Now, a new study has found that potatoes exist because of a lucky accident: A natural interbreeding between two wild plants. 

Nine million years ago, an ancient hybridization event between the ancestors of today’s tomatoes and a potato-style plant known as Etuberosum made potatoes possible. 

A team of genomic experts, supported by taxonomy and evolutionary biology experts, analyzed 450 potato genomes, including domestic types, and 56 wild relatives.  

“Wild potatoes are very difficult to sample, so this dataset represents the most comprehensive collection of wild potato genomic data ever analyzed,” said lead study author Zhiyang Zhang in a statement. 

The goal was to discover why modern potato plants resemble wild species of the Etuberosum group – even if those don’t carry the tubers – while some parts of their genome reveal a closer evolutionary link to tomatoes. 

The analysis confirmed that the potato carries a balanced genetic legacy from both ancestors, with key genes from each enabling tuber formation. 

One gene, SP6A, which signals tuberization, was inherited from the tomato lineage but the potatoes only evolved the thick, starchy underground storage organ present today when paired with another gene, IT1, a gene inherited from Etuberosum that shapes underground stem growth.  

“These results make us look at our humble potato in a very different light: potato and all its wild relatives came to exist thanks to a chance encounter of two very different individuals,” said study author Tiina Särkinen. “That’s actually quite romantic.” 

This genetic turning point occurred as the Andes mountains were rising rapidly, during a period of major environmental shifts caused by the Atlantic plate pushing beneath the South American plate. 

Phylogenetic analysis of the modern descendants of the two “parent plant” lineages shows that they occupy different environments: Tomatoes thrive in hot, dry conditions, while Etuberosum species are adapted to temperate climates.  

The ancestor of the potato developed tubers, later potatoes, that helped it to survive the dry, cold conditions of the high Andes. These underground organs enabled the plant to reproduce without seeds or pollination, spreading into new ecosystems. 

“Evolving a tuber gave potatoes a huge advantage – it fueled an explosion of species diversity and helped potatoes thrive in some of the most challenging environments on Earth,” said study co-author Sanwen Huang. 

This study is especially significant as it might be the key to unlocking climate-resilient potato varieties, as researchers can develop potatoes into a seed crop, speeding up breeding and boosting resistance to disease and climate change. 

“Science never stops,” said study author Sandy Knapp, “it keeps asking the next interesting question.” 

Editor’s Note: In Wednesday’s Item, “Copper, Gold, and Independence: Bougainville Pledges To Be World’s Newest Country,” we said the autonomous region would be voting on Sept. 4. In fact, local officials rescheduled the vote for Sept. 5 for most polling places in the region. We were not informed of the change until after our publishing deadline. We apologize for any inconvenience.