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Frogs can't poison themselves

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D: Yaël, did you see how bright that frog’s skin was? Let’s go take a closer look.

Y: I’m fine staying here, thanks. I didn’t come all the way to South America to have a poison dart frog leap on me, Don.

D: I’d bet it’s more likely to leap away from you. The whole reason they carry toxic molecules in their skin is to deter predators from trying to eat them.

Y: You know what I’ve always wondered? If poison dart frogs’ skin is so toxic, why doesn’t it harm them? I know they get their toxins from their diet—from the mites and ants they eat—so how do they manage to be resistant to them?

D: Good question. Scientists took a look at a certain species of poison frogs that carries the toxin epibatidine to figure out those details. In short, epibatidine works by binding to a certain protein in their bodies. Over years and years of evolution, the frogs have switched out certain amino acids in that protein, which changes the protein’s shape and prevents the toxins from binding to it.

Y: Sounds like a simple solution when you put it that way.

D: There were a few complications. The protein that the toxin binds to is the same one that’s a chemical messenger critical for healthy brain function. To prevent brain impairment, the frogs had to undergo a few more amino acid changes. Eventually, the protein’s shape became such that it blocks the toxin, but accepts the chemical messenger. Pretty crafty, right?

Y: Very impressive. But I’ll still stick to admiring from afar.

A strawberry poison frog with lime green skin and brown spots sits in profile to the camera

Bright skin like this strawberry poison frog's warns predators of potential danger (John P Clare / flickr)

Poison frogs' patterns on their skin can really draw you in to take a closer look, even if the goal is to warn you away. The whole reason they carry toxic molecules in their skin is to deter predators from trying to eat them.

If poison dart frogs’ skin is so toxic, why doesn’t it harm them? They get their toxins from their diet—from the mites and ants they eat—so how do they manage to be resistant to them?

Scientists took a look at a certain species of poison frogs that carries the toxin epibatidine to figure out those details. In short, epibatidine works by binding to a certain protein in their bodies. Over years and years of evolution, the frogs have switched out certain amino acids in that protein, which changes the protein’s shape and prevents the toxins from binding to it.

Sounds like a pretty simple solution, but there were a few complications.

The protein that the toxin binds to is the same one that’s a chemical messenger critical for healthy brain function. To prevent brain impairment, the frogs had to undergo a few more amino acid changes. Eventually, the protein’s shape became such that it blocks the toxin, but accepts the chemical messenger.

Pretty impressive. But maybe still stick to admiring from afar.

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