https://www.livescience.com/planet-earth/evolution/tomatoes-randomly-mated-with-another-plant-9-million-years-ago-the-result-potatoes

Random mating between wild tomato plants and potato-like species 8 million to 9 million years ago may have given rise to one of our favorite carbs: the potato.

Together with 107 extant, wild potato species, the cultivated potatoes we know today (Solanum tuberosum) belong to the lineage Petota. New research suggests that this lineage, or group of closely related species, emerged from interbreeding between the ancestors of two other lineages: Tomato, which consists of 17 living species, including the salad essential Solanum lycopersicum, and Etuberosum, which has three living species native to South America.

The importance of interbreeding in this case, Knapp said, is that it created new combinations of genes in the Petota lineage, giving rise to tubers — the swollen, underground organs that store water and nutrients, which humans eat. The ancestors of modern Tomato and Etuberosum plants did not have tubers, and these structures have not appeared in either lineage since they interbred to produce a hybrid.

"Our findings show how a hybridization event between species can spark the evolution of new traits, allowing even more species to emerge," study co-author Sanwen Huang, a professor of agricultural genomics at the Chinese Academy of Agricultural Sciences, said in a statement. "We've finally solved the mystery of where potatoes came from."

The researchers analyzed the genomes of 128 Petota, Tomato and Etuberosum plants to resolve the evolutionary relationships between these lineages. They used advanced genomic tools that were not previously available, explaining why scientists haven't obtained these results before, Knapp said. The team published its findings Thursday (July 31) in the journal Cell.