The potato, often regarded as the epitome of ordinariness, is a staple that has captivated taste buds across the globe. However, beneath its humble exterior lies a complex genetic lineage that has long puzzled scientists. Sandy Knapp, a botanist at the Natural History Museum in London, highlights the intrigue surrounding the ancestry of potatoes.
Researchers have established that potatoes are closely related to tomatoes and a group of plants known as Etuberosum. Despite their charm—including vibrant purple flowers—these connections led to a conundrum: genetic evidence suggested potatoes had a closer relationship to tomatoes, while other data pointed towards Etuberosum.
This conflicting information prompted the researchers to seek clarity. A recent paper published in the journal Cell offers a compelling explanation: the confusion arises from an ancient interbreeding event between the ancestors of tomatoes and Etuberosum. This pivotal event gave rise to the potato lineage, coinciding with the emergence of new high-elevation habitats in the Andes.
Knapp and her colleagues believe understanding this hybridization could lead to the development of a “greater tater” — a potato that can withstand various challenges, from disease to climate change.
In Knapp’s own kitchen, she showcases a perfectly cooked potato, stating, “These ones are really good boiled.” She explains that all the varieties of potatoes we consume today, whether red, small, or suitable for chips, originate from one domesticated species that began its journey in the Americas. Currently, there are 107 wild potato species in existence, each notable for producing underground tubers that serve as starch storage for the plant, enabling it to endure unfavorable growing seasons.
Interestingly, neither tomatoes nor Etuberosum produce tubers. This led Knapp and her team to investigate further by sequencing the genomes of various plants, including Etuberosum, tomatoes, and numerous wild and domesticated potatoes. Their findings revealed that modern potatoes possess a balanced mix of genes from both tomatoes and Etuberosum, supporting their theory of a long-ago hybridization event.
Yiyuan Ding, a bioinformatics Ph.D. student and lead author of the paper, emphasizes the significance of this discovery, as it provides insights into the evolution of the potato lineage. “It’s a chance event,” Knapp reflects. “Sometimes things work, and sometimes they don’t. We’re quite lucky in this case that this one worked.”
This successful hybridization appears to have occurred around 9 million years ago, a critical juncture when the Andes mountains formed, creating suitable conditions for the new potato lineage. Tomatoes and Etuberosum face challenges in such high elevations due to their specific environmental preferences, but potatoes thrived, making the most of their unique adaptation.
“Potatoes combined the best of both worlds and explosively speciated in the Andes,” Knapp explains. With the ability to store energy in their tubers, these plants became adept at surviving harsh conditions, waiting for the right moment to reproduce. The “tuber is a good weapon” against the rigors of high-elevation habitats, says Zhiyang Zhang, a plant genetics Ph.D. student and lead researcher on the study.
About 6,000 to 7,000 years ago, human civilizations near Lake Titicaca began to domesticate a specific potato species, leading to the diverse varieties we are familiar with today. This transformation of the potato from a wild tuber into a staple crop symbolized a critical turning point: from nature’s gift to humanity’s agricultural treasure.
The findings of this research carry practical implications for future potato cultivation. Traditionally, farmers propagate potatoes using small chunks of the tuber, resulting in a genetically identical crop that is susceptible to diseases and environmental changes.
Knapp suggests that this study could facilitate a shift in how potatoes are cultivated, exploring the potential of genetic engineering through tomatoes or Etuberosum to enhance potatoes. This could enable the production of robust seeds, allowing farmers to breed potatoes that resist pests, adapt to climate challenges, and thrive in varied environments.
“The tomato can be the future of the potato,” remarks Zhang, highlighting the transformative potential of this research. Iris Peralta, an agronomist from the National University of Cuyo in Argentina, lauds the application of modern genomic tools in uncovering the potato’s origin story, suggesting that similar hybridization events likely contribute to the diversity of other plant lineages as well.
The authors underscore the importance of hybridization as a driving force in evolution, enabling the emergence of new species and the variation necessary for adaptation in changing environments. “Through hybridization, you can generate many new combinations in a short time,” Zhang concludes.
While it’s worth noting that not all interbreeding produces successful outcomes, the story of the potato underscores a remarkable event in evolutionary biology that shaped a globally cherished food source from two plant relatives.
In essence, the potato’s genetic journey reflects a broader narrative of adaptability and evolution, and as scientific advancements continue to explore its lineage, we may see the emergence of new generation of potatoes — robust and resilient — that can meet our future agricultural challenges head-on.
image source from：npr
