I'm Ira Flato, and you're listening to Science Friday.

Today on the podcast, they trip down the produce aisle, including how mushrooms from some of those popular mushroom kits escape into American forests.

The tough thing is that we will never truly know exactly where they came from, but it started in general when they were brought over here to North America for commercial cultivation.

But first, I love a good tomato plant. And while I knew that both tomatoes and potatoes are members of the nightshade family,

which, by the way, includes peppers and eggplants, it was still a bit of a surprise to read

new research that found that the edible part of the potato plant, you know, that tubers at the

bottom of the plant, came from another plant cross-breeding with a tomato.

Yes, millions of years ago.

Joining me now to talk about this seemingly bizarre relationship is Dr. Sandra Knapp.

She's a merit researcher at the Natural History Museum in London, and one of the authors on

that paper. Welcome to Science Friday.

Thank you, Iris. It's great to be here. When we say that potatoes may have arisen from tomatoes

or potatoes, potato, you know, what do we mean by that? Well, I mean, it's really hard to know exactly what

happened millions of years ago.

One of the things that we've known for a really long time is when we reconstruct the phylogenetic tree of the whole of the genus Salanum, which, by the way, has more than a thousand species in it.

So it's no trivial undertaking.

One of the places where there's always been a lot of discordance, which means we never really know what

the branching pattern is, is where tomatoes and potatoes and this lineage called etuborosa is that

relationship. You never really know whether potatoes were more closely related to tomatoes than they

were to the other ones, or vice versa, or whether potatoes and etoborrosin were most closely related to one another.

So that's what we call discordance. So how do we get a potato arising from a tomato?

Well, we don't. We don't. That's the key thing, is that one of the things about studying

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