Potato tubers are a product of ancient hybridization events
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The common potato has been discovered to originate from a cross between the ancient tomato and a lesser-known South American lineage called Etuverosam.
Plants from the Etuverosam group resemble potato plants but lack one significant feature: they do not yield the starch-rich tubers that make cultivated potatoes a vital food source globally.
Sandra Knapp from The Natural History Museum in London and her team examined the genetics of three groups within the Solanum genus: Petota, which includes 107 species of cultivated potatoes, alongside 17 tomato types and three Etuverosam species. All three groups are believed to have diverged from a shared ancestor roughly 14 million years ago.
The researchers analyzed 450 genomes from cultivated potatoes and 56 wild potato species, revealing a consistent genetic mixture of tomato and Etuverosam genes across all samples.
Findings suggest that the origins of potato strains result from hybridization events with tomato ancestors, likely from a lineage situated in present-day Chile, dating back about 8 million years.
These hybridization events have led to novel gene combinations and innovations like tuber formation. “This process facilitates gene sharing, enabling new strains to produce tubers and helping these plants to thrive in newly formed, cold and arid environments,” Knapp explains.
This indicates that hybridization acts as “a significant driver of diversity evolution,” according to Knapp.
“While the edible parts of tomatoes and potatoes appear quite different, the actual plants are remarkably similar,” she elaborates. “If you happen to find a potato plant that produces fruit, it will yield green, tomato-like berries, but these are inedible and taste unpleasant.”
Brett Summerrell from a Botanical Garden in Sydney, Australia, which did not participate in the study, mentions that this new research offers substantial evidence of hybridization and resultant species diversification.
“This study underscores the necessity of understanding the evolutionary importance of crops and safeguarding their wild relatives, which may be crucial for addressing future agricultural challenges,” Summerrell emphasizes.
“Many relatives of potato-like species face threats posed by habitat destruction and climate change.”
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Source: www.newscientist.com
