[RADIOLAB INTRO]

RADIO ANNOUNCER: That incredibly talented young boy was soon a talented young man, composing symphonies, concertos ...

DAVID QUAMMEN: Hello, hello!

ROBERT KRULWICH: Hello

DAVID QUAMMEN: Robert, hi.

ROBERT: Hi, let me just ...

JAD: Wow, what was that?

ROBERT: That—that was the mist of classical music that is public radio being suddenly interrupted by science journalist and author David Quammen.

DAVID QUAMMEN: Hey, are we all here now?

ROBERT: Now we're all here.

ROBERT: And you are Jad Abumrad

JAD: Yes I am.

ROBERT: I am Robert Krulwich. This is Radiolab.

DAVID QUAMMEN: Yeah yeah.

ROBERT: And actually what happened here is I called David because he has just published a book, which contains an idea that I found so surprising. I had not known of this. It's kind of a—a smack in the face to Charles Darwin's theory of evolution.

DAVID QUAMMEN: Yes. There have been a number of accent aigu that have been added to Darwin's theory over the 150 years or so since he published it, but this is—this is more than that, this is a big fricking asterisk.

ROBERT: [laughs]

ROBERT: And to explain what that means, David told me a story about a moth.

DAVID QUAMMEN: Yes, the peppered moth. It lives in forests of central England among other places. And during the 19th century, this moth was white with little flecks of black on it. And these moths sometimes roost on the—on the trunks of trees. And the trunks of trees surrounding Manchester, England, were kind of light colored, so when these moths roosted on the trees they were pretty well camouflaged—a light, slightly peppered moth on a light, slightly peppered tree trunk. So they were protected against predation by birds. And then the tree trunks changed. Why did the tree trunks change? Because of the Industrial Revolution, because the smoke stacks of Manchester were turning out a lot of coal smoke, they were burning coal for all their industrial processes. And there was this soot, this coal soot that was coming out, and it was blanketing the trees in the nearby forest, so the tree trunks turned black. And the moths were no longer camouflaged because the moths were white.

ROBERT: You wouldn't want to be a white moth sitting against a coal-black tree because then your—your ...

DAVID QUAMMEN: No, no.

ROBERT: ... bird would know exactly where you are.

DAVID QUAMMEN: Right. What happened? The moths turned black.

JAD: Oh yeah. Sure, this is the—this is the classic sort of evolution story.

ROBERT: Exactly.

DAVID QUAMMEN: That story was told, it was—it because a textbook example of Darwinian evolutionary change in real time.

ROBERT: And the way that happens we were told, is that once the trees turned dark, the moths ...

DAVID QUAMMEN: Changed by incremental mutation.

ROBERT: Like, you know, thanks to some tiny little mistake in some moth gene ...

DAVID QUAMMEN: The black spackling got bigger on certain moths, and those were a little bit more protected. And then the spackling got a little bit bigger, the moths got a little grayer.

ROBERT: And then very, very slowly, over generation after generation after generation of moths, they get a little bit darker, and then darker still, until you end up eventually with a population of moth that turns completely black.

DAVID QUAMMEN: That's the classic story.

ROBERT: Except ...

DAVID QUAMMEN: Except that we now know that's wrong.

ROBERT: It turns out it wasn't slow. It didn't take generations and generations.

DAVID QUAMMEN: Sequencing of the moth genome has revealed a stretch of DNA, 22,000 letters of the DNA code, that suddenly jumped into these moths from somewhere, and in a flash the moths changed from white to black.

ROBERT: Pretty much in one day, really, a white peppered moth mom all of a sudden produces an all black baby.

JAD: Wait so how did that—how did that happen? A whole packet of genes just got shoved into this new—where did it come from?

ROBERT: Well, David says it probably jumped from one part of the moth genome to a completely new part, different part. But what that means, of course, is that living things, it turns out, can change way faster than we thought, and therefore evolution can happen much faster than we thought. And on top of that, David says, scientists have now discovered this even stranger kind of super fast change that takes things about parents and offspring, individual species, things we've counted on for years, and just throws the whole mix into the air.

DAVID QUAMMEN: Yes. Infective heredity.

JAD: Infective heredity. What is—what is that?

ROBERT: Oddly enough, to explain this to you I have to go back ...

JAD: Hello I'm Jad Abumrad.

ROBERT: And I'm Robert Krulwich.

JAD: And this is Radiolab.

ROBERT: ... to an earlier version of us, because it was 11 years ago I think that we made a show called "(So-Called) Life."

JAD: Life, not as we know it.

JAD: Oh, God. That show?

ROBERT: And in that show, we dealt with an early sort of more primitive version of this very question. So I'm just gonna play you a few minutes of that—of that earlier show.

ROBERT: Well, let's talk about life, you and I.

ROBERT: And we'll come right back.

ROBERT: When you look around at the world at living things and I say "Look Jad, there's a cat, and next to that is a dog, and that's a tree." And you notice that those things, of course, are different.

JAD: Yes

ROBERT: And then later when we go to school we learn about phylums and categories like kingdoms and stuff, so we think about the nature of those differences. And then you're taught about struggle, and competition ...

JAD: Darwin, and species and the fittest. And yeah

ROBERT: Darwin, and species, and all that. There is a new theory that's being talked about that turns all of that on its head. I heard it first from this guy.

STEVE STROGATZ: I'm Steve Strogatz. I'm an applied mathematician at Cornell.

ROBERT: And the story he told me, which is based on analysis of DNA in very tiny organisms ...

STEVE STROGATZ: Microbes.

ROBERT: ... is that once upon a time, he says, life began with a very primitive, very simple collection of cells. And these cells, said Steve ...

[ARCHIVE CLIP: [singing and laughing]]

ROBERT: ... these cells like to share.

STEVE STROGATZ: It appears that as you—when you go back far enough, there's a kind of rampant sharing of molecules. It's a kind of orgy in which there are no well defined species or organisms, and I can give you my genes and you can pass—we're a commune.

JAD: I totally remember recording that.

SOREN WHEELER: The kumbaya singing?

ROBERT: That's Soren Wheeler who was there at the start. He produced this piece years ago.

JAD: Yes!

SOREN: I think it was just us around the office humming.

JAD: Yeah.

STEVE STROGATZ: It was a commune.

JAD: What does—what does that mean it was a commune?

ROBERT: What do you mean, what does it mean?

JAD: Well, I mean, I know what it means in the '60s free love sense, but what does it really mean?

ROBERT: What cells are exchanging is chemicals. Chemicals that give them talents and traits, genes. Here's what happens—I did this with Steve. In our ancient puddle, I mean, Darwin thought that life might have begun in a warm puddle.

JAD: Mm-hmm.

ROBERT: Let's say that you and I are both cells.

STEVE STROGATZ: Okay

ROBERT: So once upon a time, there was you in a puddle and I'm in the same puddle as you.

STEVE STROGATZ: Mm-hmm.

ROBERT: And it gets a little colder in the puddle, so we should all get sick. But you don't get sick. You have some kind of accidental talent. You can handle cold water. I'm shivering. Describe again what happens at this point?

STEVE STROGATZ: [laughs]

ROBERT: In the glorious old days?

STEVE STROGATZ: Well, my membrane—that is I'm a cell, I've got a membrane, I've got my outer layer. Maybe a little bit porous, and maybe—whoops! Some of my genes just leaked out.

ROBERT: [laughs]

STEVE STROGATZ: [laughs] Okay, we're not talking sophisticated organisms.

ROBERT: Right.

STEVE STROGATZ: And maybe you're porous too, and, oh wow, you just absorbed some of those genes.

ROBERT: So now we both have this.

STEVE STROGATZ: We both got it.

ROBERT: We both got it. And if I've got this gene now, I can survive cold water because it's part of me. And if I bump into you, now it's part of you. So now this Steve gene has become a Robert gene, which has then become a Jad gene, and we're doing this over and over and over, and we're getting really communal.

[ARCHIVE CLIP: [singing and laughing]]

JAD: It sounds so friendly.

STEVE STROGATZ: No, no. Actually, it ...

ROBERT: Don't think of cells like people. Shut up! All these exchanges, this gene swapping, was not intentional.

NIGEL GOLDENFELD: It's not purposeful sharing.

ROBERT: That's Nigel Goldenfeld.

NIGEL GOLDENFELD: I'm a theoretical physicist at the University of Illinois.

ROBERT: And he and his colleague Carl Woese did the science that led to some of these kind of goofy ideas.

NIGEL GOLDENFELD: It's not me sort of saying "Hey, I'm gonna just help out my buddy over there, here's a couple of genes that I think you'll find handy." It's not something like that.

JAD: Even still, if we're swapping genes so much and, you know, you're giving me yours and I'm giving you mine ...

ROBERT: Yeah?

JAD: What does it actually mean to be me?

ROBERT: Yeah.

JAD: If so much of me is spread around?

ROBERT: Well, it would be very weird. Imagine a world in which, for a while, I have your nose—God forbid! [laughs]

JAD: [laughs]

ROBERT: And then I get my nose back. You have Steve's hair, then Steve would get my ear, then he would get your nose.

NIGEL GOLDENFELD: Once you start having a lot of exchange ...

JAD: I'll take your chin.

ROBERT: Okay. And you can have my allergies.

NIGEL GOLDENFELD: And then you start even asking what does it mean to be a species.

JAD: You can have my love affair with doubt.

ROBERT: [laughs]

NIGEL GOLDENFELD: You may not even be able to talk about individuals.

ROBERT: Yeah.

STEVE STROGATZ: If the mixing is good enough, we're all kind of indistinguishable. So identity would be very strange in this ancient world.

NIGEL GOLDENFELD: A lot of the concepts that we take for granted in biology become more and more nebulous as you get further and further back to the root of the origin of life.

ROBERT: Take, for instance, Charles Darwin. What Nigel's really saying is for the first billion years of life ...

JAD: With a B.

ROBERT: With a B. Everything that Darwin teaches, all that stuff hasn't happened. There's no borders, no individuals, there's no species.

STEVE STROGATZ: That is, Darwinism, evolution as we now understand it, that's an interlude in the real story of life. It's only what's happening now.

ROBERT: What you got back at the very beginning was a whole bunch of cells swapping genes, swapping advantages, swapping disadvantages, and it's kind of a wild time.

STEVE STROGATZ: A tremendous explosion of diversity in a way that life has not seen since then.

ROBERT: Until one dark and terrible day ...

JAD: [laughs]

ROBERT: ... three billion years ago. As interpreted by Freeman Dyson.

JAD: Freeman Dyson.

ROBERT: The famous physicist, and delivered here now by our friend the mathematician Steve Strogatz. Here's Steve.

STEVE STROGATZ: One evil day, a bacterium, anticipating Bill Gates by three billion years, refused to share. Refused to share.

ROBERT: Ooh!

STEVE STROGATZ: The first bad guy is this cellular Bill Gates, who decides that I've got an innovation that I don't feel like sharing, or possibly I've found a way to keep my membrane from leaking. That is, I'm not gonna be a sharing soul any more.

JAD: And why? I mean, what made that one little cell decide to stop sharing?

STEVE STROGATZ: That's a good question. We don't really know.

ROBERT: But what we do know ...

STEVE STROGATZ: This is—was maybe the most dramatic moment in the history of life on Earth. This transition from the age of, if you want to call it the age of sharing, to the age of selfishness.

ROBERT: And gradually, once one creature stopped sharing, pretty soon the others followed, and then more and more did the same thing. And now, for the first time in the history of life, finally we get Darwin. Now we get species. Now we see differences.

STEVE STROGATZ: Yes it's the age of identity, of individualism. It's also the age of—of stasis.

ROBERT: Things change but they change much more slowly.

STEVE STROGATZ: And any great thing, you know, like you are a bat and you figured out sonar. I don't have sonar. I can't get sonar. [laughs]

ROBERT: [laughs]

STEVE STROGATZ: It'd be nice to have sonar. Or like you're a little electric fish that lives in the muddy waters of the Amazon. You don't care it's totally dark, you can see because you can see with electricity. I can't see with electricity. If I'm in the dark, I'm bumping my head.

JAD: Did we really use Bill Gates as a stand in for, like, selfishness?

SOREN: Yeah. Well, I mean, at the time, he was the ultimate corporate ...

JAD: Oh that's horrible that we did that.

SOREN: I know, given the Gates Foundation.

STEVE STROGATZ: That's right. He's actually gone over to the light side instead of the dark side.

SOREN: Yeah, right. Exactly. That is Steve Strogatz. I ended up calling him up just to chat him through some of this stuff. And he told me that he actually heard this whole idea from a lecture by physicist Freeman Dyson.

STEVE STROGATZ: Dyson is just a great writer and a great speaker, and he had this memorable line in there—at least memorable to me—when he started talking about—I mean he phrased the whole thing in terms of sharing, which may be why in that previous episode we had that kumbaya singing. That wasn't my doing by the way.

SOREN: No, no. That was—that was us.

STEVE STROGATZ: Yeah. But anyway, so then he said, "But one evil day some primitive bacterium, anticipating Bill Gates by three billion years, refused to share its DNA."

SOREN: Oh, so that was—that was Freeman Dyson's line.

STEVE STROGATZ: That's his. Yeah, that was his joke. So anyways, I was sitting there in this lecture and he started mentioning a certain biologist, Carl Woese. And he talked about him in such glowing terms as one of the great microbiologists of our time. And ...

SOREN: So you—so you hadn't heard of Carl Woese before that?

STEVE STROGATZ: No I had not.

SOREN: So the reason I was asking is that ...

ROBERT: I think in the show we actually mentioned Carl Woese, as I remember it.

SOREN: You know, I don't know if you guys know this or not but that was 11 years ago, right? I was actually an intern at the time. I'd just showed up, and I was tasked with tracking down Carl Woese, who's the guy that we mentioned as sort of like the grandfather of this idea. And he was like, a huge, huge deal in science. He discovered this whole other branch on the tree of life, the archaea.

JAD: Oh, he's Mr. Archaea?

SOREN: Mm-hmm.

ROBERT: Which is a pretty big one. It's a whole—a whole 'nother kingdom of life.

SOREN: Yeah. It got him on the front page of the New York Times. And I had to track him down, and it turns out he was, like, the just—the classic, curmudgeonly scientist.

ROBERT: [laughs]

SOREN: It took me 20 emails to get him to even, like, just let us talk to his collaborator, Nigel Goldenfeld who we talked to in the show. But whatever, it was a very strange—he was a very curmudgeonly man. But, you know, like, he came to like me, and I actually spent some time with him in his office and we, I can do the curmudgeonly thing if I need to. You know, we shared some ...

JAD: [laughs] You've got those skills.

SOREN: Yeah, I could. We passed some curmudgeonly jokes back and forth. And anyway, after he heard the piece, he wrote me the most seething, scathing email.

JAD: Oh, no!

SOREN: About—and nothing—there was nothing in it about like, you got this wrong. It was just like "You made a cartoon of my work." Which honestly now, listening back, I agree with a little more than I did at the time.

JAD: Yeah, yeah.

SOREN: But he was like, "I'm a serious person, and you've made this into, like, a dog and pony show." And I was—like, I was brand new!

JAD: Yeah.

SOREN: And it hurt. I mean like, I was—I felt, like, really, really bad. And he's like, "You've disrespected Nigel."

JAD: Ugh!

SOREN: And so I wrote—I wrote, or I called up Steve maybe and said, "Oh, man. You know, this happened." And Steve was like, "Hey listen, forget them."

JAD: [laughs]

SOREN: "Don't worry about it."

JAD: Oh, I love Steve.

STEVE STROGATZ: Yeah, I don't know. It sounds like something I might have said.

SOREN: But do you remember having that conversation?

STEVE STROGATZ: I don't. I honestly don't remember having that conversation.

SOREN: And I was like, oh, I needed that so bad at the moment in my career, for someone like—with Steve's stature to, like, balance it out in that way.

JAD: Yeah.

STEVE STROGATZ: Yeah, I think—I mean it's a little bit funny that he would—to me, a little surprising, that he wouldn't have gotten what you were trying to do.

SOREN: Yeah.

STEVE STROGATZ: Or what we were trying to do. I think our playfulness, in an attempt to be clear, and to communicate, and to attract people who may not otherwise not listen to a story about something called horizontal gene transfer, he should've gotten that, because he himself in his writing was very playful.

SOREN: Hmm.

STEVE STROGATZ: He was very fun to talk to. I mean he was absolutely—Carl Woese was very playful and irascible and grouchy and charming.

SOREN: Yeah.

STEVE STROGATZ: But he would certainly tell you what he thought.

DAVID QUAMMEN: Yeah. Yeah, this guy is a great character.

SOREN: And David Quammen, it turns out in his new book, talks a lot, a lot a lot—about Carl Woese and this revolution in our thinking about the evolution of life.

DAVID QUAMMEN: Towards the end of his life he started to think he was more important and more profound than Darwin. He got a very negative attitude toward—toward Charles Darwin.

ROBERT: And on Darwin's birthday, he sent out a note that everybody should—that this should be a day of rage.

DAVID QUAMMEN: That's right. Yes, he did that.

ROBERT: But I guess what I'm wondering is, now that you've spent a book's attention on him, do you feel that he has some right to say that the picture we have of how life changes needs serious amending, or is he just barking because he's a barker?

DAVID QUAMMEN: No, he—he was entitled not to think that he was greater than Darwin, but to think that what he discovered was very, very damn important to understanding the full history of evolution on Earth. What has happened all throughout the history of life on the planet—four billion years—and is still happening today. This is where we are now.

ROBERT: The crazy details coming up right after the break.

[LISTENER: This is Yong Yun calling from Astoria, New York. Radiolab is supported in part by the Alfred P. Sloan Foundation, enhancing public understanding of science and technology in the modern world. More information about Sloan at www.sloan.org.]

JAD: Jad.

ROBERT: Robert.

JAD: Radiolab.

ROBERT: And we're back with David Quamman, and this new—new to us—way of changing life.

DAVID QUAMMEN: Infective heredity. These leaping genes, these transfers of DNA that create new genetic possibilities in a blink.

ROBERT: Turns out, David told us, that the swapping of genes that we talked about in the early history of life, that's still happening today.

DAVID QUAMMEN: Correct. Yes.

ROBERT: Bacteria all around us.

DAVID QUAMMEN: Those bugs are trading genes. Genes are jumping sideways from one kind of bacterium to another. Even in our bellies, even in our guts.

ROBERT: Huh! So let's say that you go to France on a vacation, and you touch something there. And then you lick your finger. I don't know. Or you eat something. Now new bacteria from that European food is gonna enter your stomach, and now not only do you have some new bugs in you, but they can start trading their genes with bugs that are already in you?

DAVID QUAMMEN: Yes.

SOREN: What would that mean, like, physically? Like, would it, like, bloop out the cell wall and then ...?

DAVID QUAMMEN: Well, they've found that there are several different mechanisms for this. Two bacteria would create a little pipe, a little sort of penis-like thing between them, and genes would be transferred. But genes were moving sideways under other circumstances too. From dead, busted open bacteria into live bacteria.

ROBERT: Has it acquired this new trait at once?

DAVID QUAMMEN: Immediately.

ROBERT: Immediately.

DAVID QUAMMEN: So in an instant, a new population, even a new species of bacteria can possess all of those gradually, laboriously-acquired adaptations that another strain of bacteria evolved.

ROBERT: These bugs, they don't have to wait around for generation after generation to pick up random mutations. Our bacteria inside us can pick up whole new abilities and new tricks all at once from their new neighbors.

DAVID QUAMMEN: So for instance, one kind of bacteria could pass genes for antibiotic resistance to another completely different kind of bacteria.

ROBERT: So say you've got somebody sitting in a hospital with a staphylococcus infection. Some of the bugs inside her have figured out how to resist penicillin.

DAVID QUAMMEN: When that bug then comes out of that human and it gets left on a table in a hospital and someone else gets infected by it, then they will also have an infection that is resistant to penicillin.

ROBERT: But if, say, they happen to be in the hospital sick with something totally different, they have a different kind of harmful bacteria doing trouble, giving them trouble, then those old bacteria in them can learn in a flash from the new bacteria. Now everybody's penicillin resistant.

DAVID QUAMMEN: And that's why—that's why antibiotic resistance is spreading around the world so lickety-split. That is really important. That's a—that's a global health crisis, and the World Health Organization, among others, have called that a global health crisis. Tens and tens and tens of thousands of people are dying from that, so that's really important and urgent. But the most important part of this whole subject is not practical, it's a matter of understanding, understanding the history of life, understanding who we are.

ROBERT: Quite literally. Because according to David, the way we are, we humans are, has been affected by visits from other creatures' genes.

DAVID QUAMMEN: Yes. Eight percent of the human genome is viral DNA.

ROBERT: Eight percent of the human ...

DAVID QUAMMEN: That DNA has come into humans or into our mammal ancestors sideways.

ROBERT: So here's how that goes: like, you're sitting around and a virus gets into your bloodstream. And it travels into one of your cells, and when it's in there it drops some of its DNA into your DNA. And if it gets into an ovary cell or a sperm cell, well then it will be passed along.

DAVID QUAMMEN: So eight percent of our genome has come to us that way, from these viruses. Some of that is just gobbledygook in our genome, and some of it is instructions—in other words genes—that are still performing functions. And one of those creates a boundary layer between the human placenta and the fetus, an absolutely necessary essential boundary layer.

ROBERT: Now this is—came as a total shock to me, because after all, the thing that's really special about mammals is that ...

DAVID QUAMMEN: Female mammals, or at least placental mammals, carry young around inside the body.

ROBERT: In the history of life, this was a completely new development. I mean, you think about fish, you think about reptiles, like the dinosaurs, you think about the birds. What do they do when they have kids? They lay eggs. But now we get a creature that comes along and figures out how to keep the baby growing inside it. Of course if it does that, it has to make sure its immune system doesn't attack that baby, and the baby has to be able to poop and stuff like that and get things out, so there has to be some kind of boundary.

DAVID QUAMMEN: And how did we get that good idea? We got that good idea from a virus.

ROBERT: Long, long ago, some ancient mammal ancestor got a virus, got infected by a virus, and that virus introduced a new gene.

DAVID QUAMMEN: In the original virus, it created an envelope, a wrapping around the virus. But it has been adapted to create a different kind of wrapping, the wrapping that goes around the fetus and inside the placenta. So it carries nutrients in, it protects the fetus from the mother's immune system, and it is allowing waste products from the fetus to be carried away and disposed of by the mother.

SOREN: I mean, is this potentially the origin of mammals, and would this being the—without which if we hadn't gotten this talent from viruses we wouldn't have gotten the kinds of mammals that we have now?

DAVID QUAMMEN: That—that layer could not exist and does not function without this viral gene telling it what to do.

ROBERT: Without this little bit of—of virus DNA?

DAVID QUAMMEN: You can't be a mammal. You can't be a mother mammal and you can't be a child. In light of this stuff, and for me in light of five years of studying it and following it and interviewing people about it, the categories that we apply to the world, categories like "individual" and "species" now appear more blurry. The edges are fuzzy. Is there such a thing as a human individual? Or is a human a composite of other forms of life? And what that does say is that we are composites, we are mosaics. It's humbling and it's fascinating to think of yourself that way. Like, for me, David, so it turns out that David is not just the descendent of a Norwegian father and a German-Irish mother, but he's also viral and bacterial, and who knows what else. And I find that—I find that thrilling. I'm grateful to all those other limbs on the tree of life for the things that they've given us.

ROBERT: Thanks of course to Steven Strogatz of Cornell University, who is always willing to jump back into the pond which he long since had left and thought he'd got dried off from. David Quammen's new book is called The Tangled Tree, and it's a gorgeous book. So thanks to them.

JAD: And thanks to all of you for listening. I'm Jad Abumrad.

ROBERT: I'm Robert Krulwich.

JAD: We'll see you next time.

[music]

JAD: Wait a second. Is that Kumbaya?

ROBERT: A sly version of Kumbaya. [laughs]

JAD: You snuck it in. You Trojan horsed it.

ROBERT: [laughs]

[LISTENER: My name is Venir calling from Mexico City. Radiolab was created by Jad Abumrad and is produced by Soren Wheeler. Dylan Keefe is our director of sound design. Maria Matasar-Padilla is our managing director. Our staff includes Simon Adler, Becca Bressler, Rachael Cusick, David Gebel, Bethel Habte, Tracie Hunte, Matt Kielty, Robert Krulwich, Annie McEwen, Latif Nasser, Malissa O'Donnell, Arianne Wack, Pat Walters and Molly Webster. With help from Shima Oliaee. Our fact-checker is Michelle Harris.]

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