Solved: The Potato Origin Mystery

Summary

Podcast Summary: Short Wave – "Solved: The Potato Origin Mystery"

Host: Burleigh McCoy (Producer, NPR)
Guest: Catherine Wu (Science Writer, The Atlantic)
Date: October 7, 2025
Duration: ~13 minutes content (ads and non-content omitted)

---

Overview

This episode delves into the surprising evolutionary tale of the potato, focusing on recent scientific breakthroughs that finally solved the crop’s mysterious origins. The discussion highlights how hybridization—a process usually seen as an evolutionary mishap—is actually responsible for some of biology’s most innovative leaps, including the potato itself. Host Burleigh McCoy and guest Catherine Wu explore the science and implications behind hybridization, starting from unlikely frog mating strategies to the hybrid origins of the beloved spud.

---

Key Discussion Points & Insights

1. The Science of Hybrids: A Froggy Prelude

• Frog Case Study (00:45–02:18):
  • Female plains spadefoot toads in North American deserts sometimes choose mates from a different species during drought-prone conditions. The resulting tadpoles mature faster, increasing their survival chances before their pond dries up.
    • “It turns out the tadpoles from that unlikely union mature just a little bit faster, giving them a better opportunity to hop away as adults…” — Catherine Wu (01:13)
  • Downside: These hybrid offspring are less fertile; male hybrids are sterile and females lay fewer eggs.
  • This illustrates the long-held belief that hybrids are generally “disasters” in nature (e.g., mules, hinnies, ligers).

2. Rethinking Hybridization

• Broadening Perspectives (02:18–02:42):
  • New research shows that hybridization is far more common and not always negative:
    • ~10% of animal species
    • ~25% of plant species
    • “It can’t be a total disaster… otherwise that wouldn’t persist over time.” — Burleigh McCoy (02:33)
  • Sometimes hybrids form entirely new traits, or even new species.

3. The Potato’s Puzzling Family Tree

• Origins Mystery (04:18–07:59):
  • The modern potato came from two ancient, distinct plants—one akin to a tomato and another similar to today’s wild potato (etuberosum).
    • “Both of their descendants are around today. So one of them was a tomato plant… and the other one… looked mostly like the top half of a potato plant above ground.” — Burleigh McCoy (04:29)
  • Scientists struggled to piece together the potato’s genetic lineage because its genome contains elements of both ancestor plants.
    • “Just with all due respect to potatoes, their family tree is this total and complete mess.” — Burleigh McCoy (05:09)
  • For a long time, researchers debated:
    • Did the potato descend from the tomato, or from etuberosum, with some later genetic mixing?
    • The latest data support a single, ancient hybridization event that created the potato, rather than gradual mixing.

4. Pinpointing the Hybrid Event

• The Big Reveal (07:59–08:56):
  • Genome analysis reveals a consistent, even mix of both tomato and etuberosum genes across all potato species—evidence for a single ancient hybridization as their origin.
    • “There was probably just one event that brought the tomato and etuberosum genomes together, which means hybridization. That’s kind of the only option when you see the data…” — Burleigh McCoy (07:50)
  • This event set the foundation for the vast diversity of potato species today.

5. The First Potatoes & Plant Anatomy

• Speculating on the Original Hybrid (08:56–09:40):
  • The first potato probably wasn’t simply a “tomato growing underground.”
    • “You’re never going to get a proper potato growing on the above ground portion of a plant. And you’re never going to get a proper tomato growing on the below ground portion.” — Burleigh McCoy (09:25)

6. Scientific & Agricultural Implications

• Modern Impact (09:40–11:00):
  • Understanding the potato’s hybrid origins may someday help breeders improve disease resistance and crop usability, though there are no concrete plans yet.
  • The potato’s four sets of chromosomes (“tetraploidy”) make breeding challenging:
    • “Cultivated potatoes… have four copies of every chromosome. And that’s a real pain for breeders.” — Burleigh McCoy (09:55)
  • Hypothetical future: Tomato plants engineered to grow their own tubers (underground potatoes), leading to “fries and ketchup from the same plant.” (10:50)
    • “Oh, my gosh, that would be so amazing.” — Catherine Wu (11:00)

7. Hybridization’s Broader Significance

• Rewriting Evolutionary Stories (11:41–12:56):
  • Previously considered evolutionary dead-ends, hybrids are now seen as sources of innovation—sometimes even driving bursts of speciation and environmental adaptation.
    • “…sometimes those offspring are so different in interesting and exciting ways from their parents that they’re able to do things that neither of their parents could. And that can lead to really incredible events…” — Burleigh McCoy (12:23)
  • Hybridization is recognized as influencing not just plants and animals but possibly even human evolution.

---

Notable Quotes & Moments

• On surprise hybrid origins:
  “Team both was not on the table.” — Burleigh McCoy describes the surprise that neither team “tomato” nor “etuberosum” was correct, but a hybrid origin was (06:27).

• On plant anatomy:
  “You’re never going to get a potato… growing on the above ground portion of a plant. And you’re never going to get a proper tomato growing on the below ground portion.” — Burleigh McCoy (09:25)

• On scientific possibility:
  “It could be the case that someday you’re eating fries and ketchup and they came from essentially the same plant.” — Burleigh McCoy (10:55)

• On hybridization’s value:
  “…sometimes those offspring are so different… they’re able to do things that neither of their parents could. And that can lead to really incredible events…” — Burleigh McCoy (12:23)

---

Timestamps for Key Segments

• 00:45–02:18: Hybrid frog mating and why hybrid offspring usually struggle
• 02:18–02:42: Hybrids are more common and successful than assumed
• 04:18–05:57: What were the potato’s ancestors?
• 05:57–07:59: Why tracing the potato’s family tree confused scientists
• 07:59–09:40: Evidence for single hybridization event; what the first potato could have looked like
• 09:40–11:00: How understanding hybrids might shape future agriculture
• 11:00–12:56: Hybrids as evolutionary innovators

---

Conclusion

This engaging episode reveals how a reconsideration of hybridization—once viewed as a biological mishap—sets the stage for entirely new traits and species, with the potato as a shining example. The solved origin mystery heralds a new understanding of evolution, where even the most humble hybrid can reshape life as we know it. The episode ponders future agricultural innovations and highlights that the story of the potato is really a celebration of nature’s creative twists.

Transcript

[Sponsor/Advertisement Voice]

This message comes from Bonterra. Your nonprofit's mission is big, but your team is small. With fundraising software from Bonterra's network, for good, you can focus on changing lives. Big impact, less stress. Learn [e-mail] NFG.

[Burleigh McCoy]

You're listening to Short Wave from NPR.

[Catherine Wu]

Hey, Shortwavers. Producer Burley McCoy in the host chair today with a biology mystery that I learned about from Catherine Wu, a staff writer for the Atlantic covering science. And a couple years ago, she was talking to a scientist as part of her recent kick reporting on frogs, as one does.

[Burleigh McCoy]

And she was talking to me about.

[Catherine Wu]

Hybrids, hybrids, the result of members of two different species mating. In this case, two different species of frogs.

[Burleigh McCoy]

It just struck me as so bizarre that that there would be a situation in which one frog was seeking out a mate of another species. It made zero sense. It had made zero sense to the researcher at the time she discovered it. I basically had to know more.

[Catherine Wu]

In her reporting, Katie learned that female plains spadefoot toads that live in the North American desert actively choose to mate with males outside of their species when the pools they're in are at higher risk of drying up. They do this because it turns out the tadpoles from that unlikely union mature just a little bit faster, giving them a better opportunity to hop away as adults before the pools dry up, which would be a mushy death if you're a not quite ripe tadpole. But there's a catch.

[Burleigh McCoy]

The offspring are less fertile, so the males are totally sterile and the females don't produce as many eggs because the.

[Catherine Wu]

Fitness of hybrid animals across nature is often subpar, like these froggy fertility issues or other problems. Biologists have long thought of interspecies mating.

[Burleigh McCoy]

As a disaster most of the time. Think of the sterile hinnies and mules that come out of horse donkey unions. You think of kind of sad looking ligers that come out of lion, tiger unions and zoos. And this was really the predominant thinking for decades and decades and decades.

[Catherine Wu]

That is until recently.

[Burleigh McCoy]

There are these estimates that are probably unique underestimates at this point that something like 10% of animal species and 25% of plant species do regularly mate outside of their own species. And it's not a total disaster. It can't be otherwise. That wouldn't persist over time.

[Catherine Wu]

Scientists are finding that sometimes hybrids can form brand new traits.

[Burleigh McCoy]

Neither of its parents could form anything that even looked like a potato. And somehow their offspring did.

[Catherine Wu]

Today on the show, the ingenuity of hybrids. We move from frogs to how scientists resolve the mysterious origins of a beloved staple, the potato, and how this and other hybrid stories are reshaping scientists notions of them. You're listening to Shortwave, the science podcast from npr. This message comes from Charles Schwab. When it comes to managing your wealth.

[Burleigh McCoy]

Schwab gives you more choices like full.

[Catherine Wu]

Service, wealth management and advice when you need it. You can also invest on your own and trade on think or swim. Visit schwab.com to learn more.

[Sponsor/Advertisement Voice]

This message comes from dell technologies. Dell AI PCs are newly designed to help you do more faster. That's the power of Dell AI Powered by Intel Core Ultra processors. Upgrade today by visiting Dell.com deals support.

[Catherine Wu]

For NPR and the following message come from Indeed. Just realizing your business needed to hire someone yesterday, speed up your hiring right now with Indeed. Claim your $75 sponsored job credit now@ Indeed.com shortwave. Terms and conditions apply. Okay, Katie, let's start with where potatoes come from, which is from two very old, distinct species of plants. Do you know what those two plants looked like?

[Burleigh McCoy]

So I could not responsibly describe for you what two roughly 9 million old plants looked like, but you can sort of guess because both of their descendants are around today. So one of them was a tomato plant. We all can kind of picture a tomato plant, like nice, beautiful reddish kind of fruits on a leafy green plant. And the other one, if you've ever seen the top half of a potato plant above ground, it looked mostly like that. Leafy green, some nice flowers on top.

[Catherine Wu]

Okay, so these are the two parents of the what resulted in the potato. And I didn't realize that this was like a lost love story that no one really knew the answer to. But apparently it stumped scientists for a long time.

[Burleigh McCoy]

Yeah. And, you know, a bunch of them put it to me this way, you know, just with all due respect to potatoes, their family tree is this total and complete mess. I can relate, actually.

[Catherine Wu]

I think a lot of people can.

[Burleigh McCoy]

Yeah, potatoes are messy. Lots of family drama. But basically they know that there's more than 100 potato species around today. But when they try and trace those back in time and figure out where did all of them come from, what was sort of the inciting event that spawned this massive diversity of species, they end up getting stumped. You know, potato genomes are really complicated and they seem and so they can't just piece it together really easily like they can for some other plant groups. But they had a couple ideas. So potatoes are within this big group called the Nightshades which actually does include, you know, the tomato, one of its parents.

[Catherine Wu]

We now know this makes sense as a gardener.

[Burleigh McCoy]

Yeah. But also eggplants and peppers. This is a very delicious, very productive family. But they couldn't figure out exactly where potatoes had come from. The two main candidates were actually tomato and etuberism, which is the other parent in the story. But scientists were basically always considering one or the other tomato or etuberosum for the answer to. Now we both is a little bit mind blowing because you don't expect it to be this love story that yields a hybrid that becomes the potato. You figure, oh, it's most closely related to the tomato. No, it's mostly related to etuberosum. It was a team tomato or team etuberism story? Team. Both was not on the table.

[Catherine Wu]

Okay, and so is it that they thought that the potato part of the plant evolved either when it was in the lineage of, like, the tomato plant or this etuberosum, and at some point the one with the potato crossed and that's how, like, their genes intertwined, but they never thought that it was this hybridization event, this. This coming together of two separate species that actually was the thing that created what would become the potato.

[Burleigh McCoy]

Right. So what was so confusing and frustrating about piecing together this origin story was if you looked at the potato genome, parts of it looked like the tomato genome and parts of it looked like the etuberosum genome. And so it was like, well, okay, so which did it come from? Was it that it evolved from a tomato plant that somewhere down the line just invented the potato, and then maybe, you know, some ancient potato mixed with etuberosum and that's how etourosum stuff got in the potato genome, or was it the total inverse, you know, descended from E2 Rosum then mixed with a tomato plant either on. Those are really the two main possibilities that people were considering. They didn't find that all the species they looked at had roughly the same mix of tomato and itubrosum as each other. They all looked like the same medley, which means that there was probably just one event that brought the tomato and etubrosum genomes together, which means hybridization. That's kind of the only option when you see the data that they saw. So there was one event. The two genomes mixed, and that spawned an early potato, and that early potato led to the hundred plus species we see today. It wasn't that, you know, a tomato made a potato, and then weird stuff happened later on. It was that these two plants Came together initially and the potato was born. And no one ever looked back.

[Catherine Wu]

And so this big surprise, this hybridization event, led to what we know and love as the potato. I suspect we also don't really know much about what that looked like, But I want to ask, just for fun, what do you think it looked like? Like a tomato bit in the ground.

[Burleigh McCoy]

So I have no idea what the first potato plant looked like, but it probably was not a tomato growing underground. Okay. Okay. Just like, given the way that plants produce different organs, like, tomatoes come out of the flowering parts of the plant. Right. And so that is above ground. When we're talking about a potato, that is like, by definition an underground storage organ. It's a tuber. It has to kind of come out of, like the underground system where a bunch of nutrients are being stored. I mean, a potato is basically a giant nutrient storage organ. And so you're never going to get a potato. You're never going to get a proper potato growing on the above ground portion of a plant. And you're never going to get a proper tomato growing on the below ground portion of a plant.

[Catherine Wu]

Can uncovering this potato mystery help us with the spuds of today? Like, it seems like really interesting science, but can it inform how we're growing food now?

[Burleigh McCoy]

I think the answer for right now is maybe question mark, probably question mark. There is not a set in stone plan to fix everything that is wrong with potatoes today. But potatoes, the potatoes we eat, they do have issues. They are susceptible to disease and their genomes are kind of a pain to work with. So cultivated potatoes, the potatoes we eat, they have four copies of every chromosome. And that's a real pain for breeders. Just trust me on this one. It is a huge pain for breeders. And so if they can figure out a way to just use this information to improve the potato genome, make it easier to work with, maybe that could be really interesting. One sort of out of the box idea that some of the scientists who worked on this project are playing with are using this information to help tomato plants make underground tubers. So making their own potatoes. They don't know if this is entirely possible, and it will probably be extremely difficult if it is possible at all. But. But, you know, it could be the case that someday you're eating fries and ketchup and they came from essentially the same plant.

[Catherine Wu]

Oh, my gosh, that would be so amazing.

[Burleigh McCoy]

I will say scientists have kind of cheated their way to that solution before. You know, the tomato and potato plants are still closely related enough that you can Graft them onto each other so you can, you know, it's like a Franken plant, Right? That's not the same as plant.

[Catherine Wu]

You can mash them together and they stay alive and produce both things.

[Burleigh McCoy]

Yeah. It's not quite the same as coaxing a tomato, like, with genetic manipulation to make its own potatoes, but, you know, it's a little bit more like organ donation when you place the two together. Or human centipede, whichever metaphor you prefer. One is a little grosser than the other. Yes.

[Catherine Wu]

I need one of these plants now. So this example of a hybrid. And like the frogs that we talked about earlier, what do they tell scientists about how useful hybrids are?

[Burleigh McCoy]

I think these examples and a bunch of others that have emerged in recent decades are really helping to rewrite the evolutionary story on hybrids. It is still absolutely the case that most of the time, when a species mates with another organism outside its own species, it's not going to work. They probably won't have successful offspring to begin with. But sometimes it does work. Sometimes those offspring do come to be. Sometimes those offspring can reproduce. And sometimes those offspring are so different in interesting and exciting ways from their parents that they're able to do things that neither of their parents could. And that can lead to really incredible events like making lots of new species striking out into new environments, even potentially human evolution. It seems like there's hybridization in our own evolutionary history. So it can be a really, really powerful evolutionary force that can drive evolutionary innovation in a way that just mating within your own species can't.

[Catherine Wu]

Catherine Wu is a science journalist at the Atlantic. See our show notes for both of her articles on the hybrids. Thank you so much, Katie.

[Burleigh McCoy]

Always good to be here.

[Catherine Wu]

This episode was produced by me, Burleigh McCoy, and edited by our showrunner, Rebecca Ramirez. Tyler Jones checked the facts and Robert Rodriguez was the audio engineer. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting Strategy. I'm Burleigh McCoy. Thanks for listening to Short Wave from NPR.

[Sponsor/Advertisement Voice]

This message comes from Mint Mobile. At Mint Mobile, their favorite word is no. No contracts, no monthly bills, no hidden fees. Plans start at $15 a month. Make the [e-mail] switch. That's mintmobile.com switch. Upfront payment of $45 for 3 month 5GB plan required, equivalent to $15 a month new customer offer for first 3 months only. Then full price plan options available, taxes and fees extra. See Mint Mobile for details. This message comes from Mint Mobile. At Mint Mobile, their favorite word is no. No contracts, no monthly bills, no hidden fees. Plans start at $15 a month. Make the [e-mail] Switch that's mintmobile.com Switch upfront payment of $45 for 3 month 5GB plan required equivalent to $15 a month. New customer offer for first 3 months only, then full price plan options available, taxes and fees extra. See Mint Mobile for details.