A groundbreaking study has revealed that modern potatoes originated from an ancient cross between a tomato-like plant and a potato relative about 9 million years ago in the Andes. The findings, published in Cell on September 18, shed new light on the genetic origins of one of the world’s most important staple foods.
- Origin traced back 9 million years
- Hybridization between a tomato ancestor and Solanum etuberosum
- Discovery explains the creation of tubers
- Potential for developing more resilient potato varieties
Table of contents:
- Sandra Knapp and the genetic legacy of Solanum etuberosum
- Salomé Prat and the complexity of hybrid evolution
- Adaptation in the Andes and spread to Europe
- Modern challenges and future breeding opportunities
Sandra Knapp and the genetic legacy of Solanum etuberosum
Researchers discovered that about half of all potato genes came from tomatoes, while the other half originated from Solanum etuberosum, a South American species. Sandra Knapp, a botanist at the Natural History Museum in London, emphasized that a single hybrid cross was responsible for combining these genes.
One critical gene, SP6A from the tomato line, acts as a master switch for tuber formation. Another, IT1 from S. etuberosum, drives the growth of underground stems. Experiments confirmed that without IT1, tubers remain tiny, and without SP6A, tubers fail to form at all.
This combination of genes enabled the creation of swollen underground stems that became tubers. These tubers spread across approximately 180 wild potato species and thousands of cultivated varieties.
Salomé Prat and the complexity of hybrid evolution
Salomé Prat, a plant biologist at the Centre for Research in Agricultural Genomics in Barcelona, explained that the hybridization process did not immediately result in tuber formation. According to her, the evolutionary story is more complicated. Some hybrids may have been sterile at first, but tubers provided a unique survival advantage.
Tubers store both water and nutrients. Buried underground, they can sprout without pollination or seeds. This storage ability likely gave potato plants the time needed to regain sexual reproduction, ensuring their survival as the Andes landscape changed.
Adaptation in the Andes and spread to Europe
The hybrid nature of potatoes allowed them to thrive in diverse conditions. Tomatoes adapted to dry and warm climates, while S. etuberosum flourished in cold and wet environments. Potatoes inherited traits from both, making them resilient in cold and dry regions of the Andes.
Over thousands of years, Indigenous people in the Andes identified edible potato species among the 180 wild varieties, most of which were bitter or toxic. They cultivated and domesticated many forms, creating thousands of edible varieties. Spanish explorers later carried these potatoes to Europe, where they spread worldwide as a crucial food source.
Modern challenges and future breeding opportunities
Today, cultivated potatoes (Solanum tuberosum) face challenges linked to reduced genetic diversity. Selective breeding for high yield and disease resistance has led to a loss of original genetic variability, leaving modern potatoes more vulnerable to climate change, extreme heat, and flooding.
By identifying the ancient genes inherited from both tomato ancestors and S. etuberosum, researchers see opportunities to restore lost traits. Traditional breeding and genetic engineering could reintroduce resilience to modern crops.
Sandra Knapp stressed that this genetic knowledge may lead to new varieties capable of withstanding environmental stress, ensuring the potato remains a secure food source for future generations.
Source: Science News Explores