Scientists Solved the Mystery of Where Potatoes Actually Came From
If someone told you that potatoes and tomatoes share a common origin story, you might find that hard to believe — one grows underground, the other dangles from a vine, and they taste nothing alike. But a new scientific study published in the journal Cell has confirmed exactly that. Roughly 8 to 9 million years ago, two wild plant lineages mated with each other, and the result of that ancient union was the ancestor of every potato on Earth. It is one of the most surprising plant origin stories scientists have ever uncovered.
To understand the discovery, it helps to know how scientists group plants. Modern cultivated potatoes — the ones you find at every grocery store, known scientifically as Solanum tuberosum — belong to a large plant lineage called Petota, which includes over 100 wild potato species. The lineage called Tomato contains 17 living species, including the common salad tomato. A third lineage, called Etuberosum, has just three wild species and lives in South America. For years, scientists knew these three groups were related to each other, but they could not agree on exactly how. The new research finally settles that debate with a clear answer: Petota — the potato lineage — emerged when ancient ancestors of Tomato and Etuberosum interbred and created a hybrid offspring. A hybrid is a new organism produced by the mating of two genetically different parent groups.
The research team analyzed the genomes — the complete sets of genetic information — of 128 plants from all three lineages. Using advanced genomic tools that were not available to scientists until recently, they found a striking pattern in the potato genome. The genetic data was what the researchers described as mosaic-like, meaning it contained an almost perfectly even mixture of DNA from both the Tomato and Etuberosum lineages. Think of it like a quilt sewn together from two completely different fabric collections — the final product carries equal evidence of both sources. That mosaic pattern was the key clue that potatoes were born from hybridization rather than evolving from just one ancestor.
The most important result of this ancient mating event was the development of tubers. A tuber is a swollen underground organ that a plant uses to store water and nutrients — and the potato itself is a tuber. Neither Tomato nor Etuberosum plants produced tubers before they hybridized, and neither lineage has produced them since. The trait appeared only in the new hybrid lineage and has stayed there ever since. Scientists identified two specific genes responsible for tuber formation: SP6A, which came from the Tomato lineage and controls when a plant begins producing tubers, and IT1, which came from the Etuberosum side and helps shape the tuber itself. These two genes, inherited from different plant families, combined to create something entirely new.
Timing turned out to matter enormously. Around the same period as this hybridization event, the Andes mountain range in South America was rising rapidly, creating vast new stretches of cold, dry, high-altitude land. Most plants could not survive in those conditions, but the newly formed potato plants had their underground storage organs to rely on. Their tubers let them stockpile resources and endure the harsh mountain environment where other plants failed. This gave potato plants a massive survival advantage, and over millions of years they diversified into more than 100 wild species spread across the Andes. Sandra Knapp, a research botanist at the Natural History Museum in London and co-author of the study, explained that the tuber allowed these plants to expand into newly created cold, dry habitats in the rising mountain chain.
The broader lesson here goes beyond potatoes. This discovery shows that some of the most important traits in the natural world — traits that entire civilizations have come to depend on — can emerge from a single chance encounter between two different species. Sanwen Huang, a professor of agricultural genomics at the Chinese Academy of Agricultural Sciences and co-author of the study, summed it up well: the hybridization event sparked the evolution of new traits, allowing even more species to emerge. Today, potatoes are among the most widely consumed foods on the planet, feeding billions of people across vastly different cultures and climates. All of that traces back to one accidental meeting between two ancient wild plants on the slopes of a rising mountain range millions of years before humans ever arrived.
Source: Live Science