This is Origin Stories, the Leaky Foundation podcast.

I'm Meredith Johnson.

Today on the show, we're talking about one of the things that makes humans different from other animals, our hair.

From why we have it on the top of our heads instead of all over our bodies,

to how we evolved so many variations in color, texture, and curliness.

Our guest is Dr. Tina Lassisi.

She's an assistant professor at the University of Michigan,

where she leads a lab,

researching the evolution and genetic basis of human variation,

with a focus on pigmentation and hair.

She's also the host of a PBS show called Why Am I Like This?

And she's the recipient of the 2024 Science Communication Award from the Leaky Foundation

and the American Association of Biological Anthropologists.

I always frame it as we talk about humans being the naked ape,

but actually there are plenty of mammals that are naked. You have mole rats, elephants,

depending on how you look at them, and definitely a bunch of mammals that are in the sea.

But we're actually the only weirdos that have no fur on our bodies, but decided to keep the fur on our heads mostly.

And that's what I emphasize is especially weird about humans and has not been studied enough for my liking.

So when we have something like this that's so, so different from other animals, what does that tell you as an evolutionary scientist?

So evolution is creative,

but also lazy. So if you find a good solution for a problem, you tend to apply it again and again. That's how we have things like convergent evolution of wings. But if you see something that has been evolved once, like scalp hair on a naked

body, that really tells you, okay, something must have happened here, some combination of

...