Potato, Meet Tomato: How the Modern Spud Was Born

“Millions of years ago, an ancient tomato had a fling with another species in the Andes -- and so was born the plant that gave rise to the spuds we love to eat today.

 

The origin of the potato has long puzzled scientists. Genetically, it is a close relative of the tomato. But in appearance, it resembles three potato-like species found in South America known as Etuberosum.

 

The problem is, Etuberosum don't have tubers -- the parts of the potato plant that grow underground, and that we eat baked, mashed or fried.

 

To solve this mystery, an international team of researchers looked at more than 100 genomes from cultivated and wild potatoes, as well as tomatoes and other plant species, in one of the most exhaustive analyses of potato genomes ever conducted.

 

An examination of these DNA sequences revealed that between eight million and nine million years ago, Etuberosum and an ancient tomato exchanged genes.

 

"We revealed that tomato is the mother of potato," said Sanwen Huang, a professor at the Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, and lead author of a recent study describing the findings.

 

The geological changes responsible for the rising Andes Mountains -- and the resulting climactic shifts -- likely brought together the two plant types, with one of the species, by chance, getting pollinated by the other, according to Loren Rieseberg, a University of British Columbia botanist and a study co-author.

 

"It is an insect making a mistake," he said.

 

This type of evolutionary event, known as hybridization, can yield species with traits not present in either parent -- in this case tubers. These underground storage organs help the potato plant store water and nutrients and enable its survival in harsh environments, like the cold and dry elevations of the Andes.

 

The researchers identified two genes, one found in the tomato and one found in Etuberosum, that together were essential to producing tubers -- a development that all but guaranteed the prehistoric potato's success.

 

Sometimes hybridization events lead to mostly sterile offspring -- for example, mules and hinnies, the progeny of horses and donkeys -- but tubers essentially allow potatoes to clone themselves. They sprout new plants from the buds on the tuber, what are colloquially known as eyes, without any need for seeds or pollination, according to James Mallet, a Harvard University evolutionary biologist who wasn't involved in the work.

 

That ability to asexually reproduce, with only one parent, likely enabled these potato ancestors to survive and spawn many other potato species.

 

Cultivated potatoes are one of the world's top staple crops, and with wheat, rice and maize are responsible for 80% of humanity's caloric intake, according to the study authors.

 

Mallet said knowledge of the potato's genetic origins -- and which genes are responsible for tuber formation -- could help create improved varieties with higher yields or potatoes that can survive in more diverse habitats.” [1]

 

Does Etuberosum store starch in the stem?

 

The Etuberosum plant does not store starch in its stem as an enlarged, starchy tuber.

 

In fact, the name etuberosum literally means "without tubers". This wild potato relative is known specifically for its lack of the underground, starch-storing structures that characterize the common potato (Solanum tuberosum).

 

Here's a breakdown of starch storage in Etuberosum and its relatives:

 

    Starch-storing structures: While Etuberosum does not produce large, starchy tubers like potatoes, it does have rhizomes, which are thickened horizontal stems that can store some nutrients.

 

This is distinct from the primary starch storage function seen in cultivated potatoes.

    The origin of the potato: The lack of tubers in Etuberosum is significant to understanding the evolution of the modern potato. A study published in the journal Cell in 2025 revealed that the modern potato is the result of an ancient hybridization event between a wild tomato and an Etuberosum plant.

    Genetic component: Research showed that the unique combination of genes from these two plants enabled the development of the potato's starchy tuber.

 

 Specifically, the wild tomato provided the gene that triggers tuber formation, while Etuberosum provided a gene that helps shape the underground stems into tubers.

 

1. REVIEW --- Science Shorts: Potato, Meet Tomato: How the Modern Spud Was Born. Woodward, Aylin.  Wall Street Journal, Eastern edition; New York, N.Y.. 04 Oct 2025: C2.