What's in a name?
"Tomatoes and potatoes don’t only sound similar and taste good together: They’re the closest of relatives, even though one has edible fruit and the other tubers. Turns out they’ve got an even stronger connection than scientists thought: According to a new study, early tomato plants hybridized with another ancestral group about nine million years ago—a tryst that yielded hybrid offspring with just the right combination of genes to make tubers. ...
That hybridization ... helped the first potatoes diversify into new regions and climatic conditions—from warm grasslands to cold mountain meadows—that neither of its ancestor lineages could inhabit so well.
Previous genomic studies had revealed that tomatoes are potatoes’ closest living relatives and that a separate group of three ancestral species, known as Etuberosum, is eerily potatolike. However, Etuberosum plants don’t grow tubers. Intrigued by this discrepancy, ... sequenced the genomes of 44 wild potato species, the three Etuberosum species, and 15 species of wild tomato. ...
team found that the wild potatoes have a uniform blend of genes from tomatoes and Etuberosum—“a signal of ancient hybridization,” ...
Tubers store nutrients, which can help a plant endure tough conditions. They also let plants reproduce vegetatively—without pollinators or even sexual reproduction—which probably helped the new lineage overcome any lingering fertility problems. ..."
From the highlights and abstract:
"Highlights
• The potato lineage is of ancient homoploid hybrid origin
• Alternate inheritance of highly divergent parental genes contributed to tuberization
• Hybridization and tuberization triggered species radiation and niche expansion
Summary
Interspecific hybridization may trigger species radiation by creating allele combinations and traits. Cultivated potato and its 107 wild relatives from the Petota lineage all share the distinctive trait of underground tubers, but the underlying mechanisms for tuberization and its relationship to extensive species diversification remain unclear.
Through analyses of 128 genomes, including 88 haplotype-resolved genomes, we revealed that Petota is of ancient hybrid origin, with all members exhibiting stable mixed genomic ancestry, derived from the Etuberosum and Tomato lineages ca. 8–9 million years ago.
Our functional experiments further validated the crucial roles of parental genes in tuberization, indicating that interspecific hybridization is a key driver of this innovative trait. This trait, along with the sorting and recombination of hybridization-derived polymorphisms, likely triggered the explosive species diversification of Petota by enabling occupation of broader ecological niches. These findings highlight how ancient hybridization fosters key innovation and drives subsequent species radiation."
Thank ketchup for your French fries (no public access)
Graphical abstract
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