Is tomato the ‘mother’ of potato? What a new study reveals

Is the beloved potato a ‘child’ of two plants, including the tomato?

Scientists have found that potatoes and tomatoes may be more closely linked than we once thought.

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New research suggests the potato evolved from a tomato ancestor around nine million years ago.

According to the study, wild tomatoes that once grew in the Andes crossed with another plant known as Etuberosum. Through a process called hybridisation, the two plants combined their genetic material and created a completely new line of plants.

So, is the potato really a ‘child’ of the tomato?

Here’s what the study says:

Did potatoes evolve from tomatoes?

A team of evolutionary biologists and genome researchers has traced the potato’s roots back to an unexpected meeting with one of its distant relatives: the tomato.

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The scientists studied 450 genomes from both wild and farmed potato varieties. Their research showed that a wild tomato plant mixed naturally with a potato-like plant known as Etuberosum around nine million years ago.

Both these plants had branched off from a shared ancestor nearly 14 million years ago, according to a study published on Thursday in the journal Cell.

At that time, neither the tomato nor the Etuberosum could grow tubers, the underground, nutrient-rich parts of plants like potatoes, yams or taro. But the hybrid plant they formed could.

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These tubers developed as a way for the plant to store nutrients underground as the climate in the Andes grew colder. Once people began farming them, they became a vital part of human diets.

Zhiyang Zhang, a researcher at the Chinese Academy of Agricultural Sciences and the lead author of the study, said, “A potato is the child of tomato and Etuberosum.”

“We did this analysis and we found, ‘Oh, he’s a child of two plants.’”

JianQuan Liu, a coauthor of the study and a professor at Lanzhou University in China, told CNN that the team used phylogenetic analysis, a method that traces genetic relationships in a way similar to drawing family trees in humans. This helped them uncover the link between the plants.

Their analysis showed that the modern potato contains a “mosaic-like” pattern of DNA, with traits inherited from both the tomato and Etuberosum. The findings suggest this mix came from a single interbreeding event between eight and nine million years ago.

This was possible because the two plants shared a common ancestor 13 to 14 million years ago. Even though they evolved on separate paths after that, they still had enough genetic similarity to interbreed some five million years later.

The new potato plant that resulted from this pairing developed tubers, a trait that scientists have now linked to certain genes. Interestingly, while Etuberosum itself does not produce tubers, the potato inherited that ability through its unique blend of genes.

Genetically, potatoes still show a closer link to tomatoes. So why do they look like one plant but behave like another?

The answer lies in their complex origins.

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Why do potato plants grow tubers?

Researchers have found that modern potatoes developed tubers thanks to their mixed ancestry, formed when the tomato and Etuberosum lineages combined around eight to nine million years ago.

This hybridisation gave rise to the first tuber-producing plants.

The study said that the genes behind tuber formation came from both parent plants.

The SP6A gene, which tells the plant when to start making tubers, came from the tomato. The IT1 gene, which helps grow the underground stems that become tubers, was passed down from Etuberosum.

This genetic mix allowed early potatoes to adapt and spread through the cold, mountainous regions of the Andes. The ability to grow tubers helped the plant store food and water underground, making it more suited to survive in harsh conditions than either tomatoes or Etuberosum.

This adaptation gave the potato plant a survival edge. It also kept it from breeding again with tomatoes or Etuberosum, eventually forming a new plant group known as Petota.