AILSA CHANG, HOST:
The potato - mash it, bake it, fry it. You would be forgiven for thinking it's kind of ordinary. But the potato's origin story, it's pretty fascinating, and we don't really know all the details yet. Now a team of researchers thinks that they know more about how the potato came to be. Ari Daniel has our story.
ARI DANIEL, BYLINE: OK, do you have a potato in your kitchen, by chance?
SANDY KNAPP: Yep, one second. I just have to get it out of the bag. It's a teeny, tiny one.
DANIEL: Sandy Knapp, a botanist at the Natural History Museum in London, holds up a perfectly respectable little spud in her Zoom window.
KNAPP: So all of the potatoes that we eat, the ones that are red, the ones that are little like this, the big ones, are one species we've domesticated that's gone worldwide.
DANIEL: A species that came from South America. Today, there are 107 wild potato species across the Americas, and the thing that all potato plants produce is underground tubers, which is the part of the plant we buy in the supermarket.
KNAPP: They're a way for a plant to store starch and, in a way, persist through seasons which are not good for growing. But what we didn't know was where the whole potato lineage came from.
DANIEL: Now, scientists have known that potatoes are most closely related to two groups of plants - the tomatoes and a cluster of three species called E. tuberosum.
KNAPP: They've got purple flowers. They're very cute. They look like potatoes, but they don't have tubers.
DANIEL: Tomatoes don't have tubers either, which was puzzling. In addition, certain genes suggested potatoes were more closely related to tomatoes. Yet, other genes implied potatoes and E. tuberosum were closer.
KNAPP: There's something funny happening. Why?
DANIEL: So Knapp and her colleagues went digging for answers. They sequenced the genomes of numerous potato plants and their relatives and found that potatoes have a balanced mix of genes from both tomatoes and E. tuberosum, suggesting that long ago, ancestors of these two groups hybridized. That is, they interbred to create a new kind of plant - one that could do something neither parent was capable of.
KNAPP: Which was to grow tubers. Neither tomatoes nor E. tuberosum have tubers. But the two sets of genes that make tubers came from each of those two parents.
DANIEL: And with that, a whole new plant lineage came to be, and the ancestor of modern-day potatoes was born.
KNAPP: It's a chance event. You know, that's the thing about evolution is sometimes things work and sometimes they don't. And we're quite lucky this one worked because otherwise, we wouldn't have potatoes.
DANIEL: The inner breeding occurred some 9 million years ago, which happened to be excellent timing for the potato. It's around when the Andes were rapidly rising and lots of cold, dry, high-elevation habitat was appearing. Tomatoes couldn't make it there. They prefer hot and dry. and E. tuberosum flourishes in cold and wet areas. But if the new potato lineage was anything like the potatoes of today, which are happy to grow in cold and dry conditions...
KNAPP: Potatoes combined the best of both worlds and explosively speciated in the Andes.
DANIEL: Something likely made possible by their tubers, which could store energy and persist in the harsh mountains.
KNAPP: Sort of the secret of their success, in a way.
DANIEL: The results are published in the journal Cell. Iris Peralta is an agronomist at the National University of Cuyo in Argentina who wasn't involved in the research.
IRIS PERALTA: You had two things, and something completely different emerged. The origin of potatoes - incredible.
DANIEL: She believes this kind of hybridization event has likely created other plant lineages, too. In addition, this study may have important applications, says Sandy Knapp.
KNAPP: We can use the tomato or E. tuberosum to perhaps do some genetic engineering to improve the potato.
DANIEL: So that it might produce something farmed potatoes don't currently have - reliable seeds for breeding potatoes resistant to disease and a changing climate, leading, one day, perhaps, to a greater tater.
For NPR News, I'm Ari Daniel.
(SOUNDBITE OF GEORGIA SONG, "IT'S EUPHORIC") Transcript provided by NPR, Copyright NPR.
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