Potatoes Evolved From Tomato Ancestor – ScienceAlert
The Humble Potato’s Secret Ancestor: A Surprising Link to the Tomato
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for centuries, the potato has been a staple food, a versatile ingredient, and a cornerstone of diets worldwide. Yet, its evolutionary journey is more complex and surprising than many realize. New research has unveiled a remarkable genetic connection, revealing that the potato shares a significant portion of its ancestry with the seemingly unrelated tomato.
Unraveling the Potato’s Genetic Tapestry
An international team of researchers embarked on a mission to understand the potato’s origins,analyzing an unprecedented 450 genomes from cultivated potatoes and 56 wild potato species. This extensive dataset, described as the most thorough collection of wild potato genomic data ever analyzed, provided the key to unlocking the potato’s genetic secrets.
A Balanced Genetic Legacy
The groundbreaking analysis revealed that modern potatoes carry a balanced genetic legacy from two ancestral species: Etuberosum and, surprisingly, the tomato. The genetic contribution is estimated to be roughly 60 percent from Etuberosum and 40 percent from tomatoes.”My wow moment was when the Chinese team showed that ALL potatoes, wild species and also land races, had basically the same proportion of tomato genes and Etuberosum genes,” stated Knapp, a lead researcher on the project. “That really points to an ancient hybridization event rather than various events of gene exchange later on. It is so clear cut! beautiful.”
This revelation suggests a single, ancient hybridization event rather than multiple instances of gene exchange over time.
Key Genes and Evolutionary Milestones
The study identified specific genes that highlight this ancestral link.One crucial gene, SP6A, which acts as a signal for tuberization (the formation of tubers), originated from the tomato lineage. However, its function in enabling tuber formation was only realized when paired with the IT1 gene from etuberosum. This gene plays a vital role in controlling underground stem growth, demonstrating a crucial genetic partnership.
The divergence between Etuberosum and tomatoes is believed to have begun approximately 14 million years ago, possibly influenced by insect pollination. This evolutionary split concluded around nine million years ago.
This period of divergence coincided with a significant geological event: the rapid uplift of the Andes mountain range. This environmental shift created ideal conditions for the emergence of tuber-bearing plants, which could efficiently store nutrients underground.
The Advantage of Asexual Reproduction
A key characteristic of tubers is their ability to reproduce asexually,sprouting new buds without the need for seeds or pollination. This trait proved instrumental in the potato’s spread across South America and, subsequently, around the globe through human exchange.
Future Directions in Potato Breeding
The insights gained from this research are already paving the way for future advancements in potato cultivation. Sanwen Huang, a professor at the Agricultural genomics Institute at Shenzhen and co-author of the study, revealed that his lab is actively developing a new hybrid potato that can be reproduced by seeds. This innovation aims to accelerate the breeding process.
Huang suggested that utilizing the tomato “as a chassis of synthetic biology” presents a promising avenue for creating these novel potato varieties,further underscoring the enduring genetic connection between these two iconic crops.
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© Agency France-Presse*