Radiolab - Sperm Tales

Episode Date: October 7, 2008

In today’s podcast, a teaser for our hour-long Sperm show. If you think you learned all there is to know from that junior high school filmstrip, think again.  

I should quite You're listening to Radio Lab, the podcast. From New York Public Radio, WNYC, and NPR. Hello, I'm Chad Aboumrod. Hello, I'm Robert Quilwitch. This is Radio Lab, the podcast. Which means it's not the broadcast. Not the one-hour show.

Not the one-hour show. It's like a little tidbit. This is a tidbit. But this is a tidbit with a teasing-purpose. Yes. Because we have, in the next few weeks, we are going to do the real shows about race and there's one about choice. There's one, however, entirely devoted to the subject of sperm. And sperm, you think, well, why would you spend so much time talking about that?

Yes, in fact, it's a very sad, sad, lonely show. Anyhow, go on. We learn a lot of things. I mean, if you open up any little basket and ask too many questions, you learn all kinds of fascinating things. That is so true, particularly with sperm. Yes. So we talked when we were preparing this hour with a woman named Joanna Ellington, a fertility expert, who runs a company with a very short name, kind of like sperm itself, ing, I-I-N-G, it's a fertility firm.

And I asked her, if you are a healthy male at the very top of your game, so you've got everything you're ever going to have, and they're all frisky little guys ready to go, what proportion of your gang would be fit and ready to do the deed? A normal ejaculate from a man is if you have 14, 1-4, 14% or more of the sperm that are normally shaped. That's very low percent. And 86% are abnormally shaped? Yeah. How do they differ from the normal?

Typically, you're going to have problems with the tail, and then that makes it so they can't swim right. They swim in a circle, can't swim fast. Some of them swim in a circle? Mm-hmm. You mean when they go bang and off you go, they just go round and round. on round, unround, and that doesn't

work very well, of course. Okay, circles, slow. Anything else? Yeah. As the sperm, get ready to be

ejaculated, the tail unwinds from around the cell. And sometimes it doesn't unwind right. It stays wound up or the very

tip of the tail stays kind of in a knot, I guess you could say, basically. So you got a knot on your tail? Yeah. Okay, so we got

some stalled out, some going in circles, some going slowly. Mm-hmm. Are there horror mutant to sperm? Yeah. There's one called GloboSpermia, and that is a very large round head. It's maybe three or four times normal size, and instead of having that oval, it's just quite round looking.

Sounds like a balloon head, big fat balloon head. Yeah, exactly. You can have sperm that have vacuels, which are basically holes in the DNA. You can have sperm that have two tails. Oh, isn't that better? No. You don't want anything abnormal. Are there double-headed ones? Yes, absolutely. Are there triple-headed ones? Probably some. This is making me nervous. Anything else? Some of them are going to be dead and not moving at all. Well, that's a problem. Yeah. In addition to that, there's many, many micro-biochemical things that they have to go through.

So if you were to actually write down everything that could go wrong with sperm as it goes to meet the eggs, it would be hundreds of little enumerations that could go wrong. But that's why men make sperm all the time. They constantly are making it, that constantly have a fresh supply. You've got to have something that can go through all the hurdles and all the barriers and make sure at the end of the day that you have the best, healthiest sperm cell that's participating in making, a baby. When you say,

that it's lonely. It's sad. That's sad. With odds like that. Remember, this is when you're healthiest. I know. When you're healthyest. What I don't get, though, is like, how does it, how does it, well, this is what

we're going to go into the show. But I'll just ask you now, how does it happen given all of those potential pitfalls? And that every sperm is outracing the other sperm. That's the public image here is that every guy that you put in is in a Woody Allen movie defense competing against his neighbor. Right. So it's Jerry versus Ted versus Andy versus Mark versus Freddie versus Billy, and they're all rushing to the goal. And what if Jerry and Ted and Mark and Farrow, whoever and Billy, are all double-headed with... Well, then they don't make it. So it's the odds are not in our favor.

But there is a level of cooperation we discovered while doing this hour that was deeply surprising. Sperm are not always about competing against each other. And this we learned from Tim Burkhead, He was a biologist at the University of Sheffield. He told us the story about it was a wood mouse, a W-O-O-O-O... Not a good mouse. Or a should... No. Not a shoot-mouse.

A wood mouse. Yes, wood mouse, which is actually a gift wood mouse. My colleague, Harry Moore, who's a sperm biologist here in Sheffield, his cat brought in a wood mouse, laid it on the dining room floor. And he looked at it and thought, gosh, that's got large testicles. He dissected it with it. That's the most unusual reaction. to a cat's gift that I've heard in a long time.

I'll say. You know, if you're a testicle guy, you're a testicle guy. You want to take a closer look. Anyway, so he dissects the, he dissects the vows, and then carefully removed the sperm inside, and then he looked at the shape of the sperm. This was interesting. All rodents, the sperm has a slightly hooked-shaped head,

but in the wood mouse, that hook is extreme, so much so that the hook bends right back and touches the head again. What Harry noticed was that it looked as though the hook was a specific adaptation to grasp the tails of other sperm. This sperm on its head was a kind of grasping hook, which suggested that maybe this sperm wanted to hold hands with something. Harry put the sperm into a kind of special sperm medium, and to his amazement, the sperm all joined up together in what he called sperm trains. Sperm T-R-A-N-S-S- Yes, like in a railway train. The tails of other sperm were held by this hook. And it's just head to tail, head to tail?

It looks, it's a bit messy. It's a bit like spaghetti moving forward. Okay. The amazing thing is, when he measured the speed at which the sperm trains moved, it was about twice that of isolated sperm. But wait a second, when, if me and 700 others of us, or 10 of us, get together at the head and swim together, our tails all increasing our speed, who gets to be the daddy sperm?

In the woodmouse, some of the sperm undergo what's called the acrosome reaction releasing this hook, and when that happens, those sperm can no longer fertilize, but they free a vanguard of sperm that then can fertilize. And then they give up for their brethren? Yeah, that's exactly it.

Wow. So then it's not fair to say that down there at the sperm level, it's every sperm for himself. In a few cases, the sperm is there for the other. guy. Yeah, but they're all part of the same ejaculate, all got roughly the same genetic makeup. All those sperm are related, so they all have more or less a common interest. See? We help each other out. Yeah, I mean, this is different. However, it is at this point

just specific to the wood mouse. So wood mouse sperm seem to have a thing going on amongst themselves. And the idea that a sperm would sacrifice itself for a brother's sperm is very nice. novel when you think about how normally this is thought of as such a competitive event. That's right. Well, any case, we hope you'll tune in for that show. It's coming up in about a month and a half. It's not really a month and a half if you're listening to this late in the week. It's a month and two weeks from now. Okay. It's a month. It's so short. It's really five weeks from now, going on four weeks. And before you know, it'll be three weeks. Do you see what I deal with? Sorin, can you take him down, please? You can't take me down? Just to pot him down, please.

Hey. Any case, so visit our website, RadioLab.org, you can find out more about anything on our website. And also, we should say we should give thanks. We are funded by the Corporation for Public Broadcasting. Hey, take him down. The National Science Foundation and the Alfred P. Sloan Foundation, who this month is honoring Flash of Genius,

the winner of the 2008 Feature Film Prize in Science and Technology at the Hampton's International Film Festival. I'm Jed Abumrad. Okay, you can put him back up now. Albert Krollwich. We'll see you soon. Very soon.