ABOUT THIS EPISODE

Today, a fast moving, sidestepping, gene-swapping free-for-all that would’ve made Darwin’s head spin.

David Quammen tells us about a shocking way that life can evolve - infective heredity. To figure it all out we go back to the earliest versions of life, and we revisit an earlier version of Radiolab. After reckoning with a scientific icon, we find ourselves in a tangle of genes that sheds new light on peppered moths, drug-resistant bugs, and a key moment in the evolution of life when mammals went a little viral.

Check out David Quammen's book The Tangled Tree: A Radical New History of Life 

This episode was produced by Soren Wheeler. 

Support Radiolab today at Radiolab.org/donate

English
United States

TRANSCRIPT

00:00:02Wait you think You're listening to radio lab radio from w and weiss That incredibly talented young boy was soon a talented young man composing symphonies can cello hello Hello robert Hi Hi Well what was that That was that was the mist of classical music in the public radio
00:00:33suddenly interrupted by science journalist and author david climate Hey are we all here now Now we're all here and you are a general moradi sam crow because his radio and actually what happened Here's I called david because he has just published a book which contains an idea that
00:00:49i found so surprising i had not known of this it's kind of ah a smack in the face to charles darwin's theory of evolution Yes there have been a number of excellent agu that have been added to darwin's theory over the last hundred fifty years or so since
00:01:08he published it But this is this is more than that This is a big frickin asterisk and to explain what that means david told me a story about a moth Yes the peppered mark It lives in forests of central england among other places And during the nineteenth century
00:01:30this moth was white with little flecks of black on and the's moths sometimes roost on the trunks of trees and the trunks of trees surrounding manchester england was sort of light colored So when these moths roosted on the trees they were pretty well camouflaged a light slightly peppered
00:01:48moth on a light slightly peppered tree trunk So they were protected against tradition by birds And then the tree trunks changed Why did the tree trunks change Because of the industrial revolution Because smokestacks of manchester were turning out a lot of coal smoke they were burning coal for
00:02:12all their industrial processes And there was this soot this cold that was coming out and it was blanketing the trees in the nearby forest So the tree trunks turned black and the moss We're no longer camouflage because the mods were white You wouldn't want to be a white
00:02:31moss sitting against the cold black tree because then you are your herd would know exactly where you are right What happened The moths turned black Oh yeah sure this is the this is the classic sort of evolution story exactly that story was told it was became a textbook
00:02:53example of darwinian evolutionary change in in real time and the way that happens what we were told is that once the trees turned dark the moths changed by incremental mutation like you know thanks to some tiny little mistake in some moth gene the black spackling got bigger uncertain
00:03:12moths and those were a little bit more protected and then the spackling got a little bit bigger the mall has got a little greater and then very very slowly over generation after generation after generation of moth they get a little bit darker and then darker is still too
00:03:26you end up eventually with a population of martha turns completely black that's the classic story except except that we now know that's wrong it turns out it wasn't slow it didn't take generations and generations sequencing of the moth genome has revealed a stretch of dna twenty two thousand
00:03:49letters of the dna code that suddenly jumped into these moths from somewhere and in a flash the moths changed from white to black pretty much in one day really a white peppered moth mom all of a sudden produces an old black baby wait so how did that how
00:04:12did that happen He said a whole packet of genes just got shoved in to this new from where you come from Well david says it probably jumped one part of the moth genome to a completely new part different part but what that means of course is that living
00:04:27things it turns out khun 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 is even stranger kind of super fast change that takes things about parents and all spring individuals species
00:04:45things we've counted on for years and just throws the whole mix into the air yes infective heredity infective heredity what is what is that oddly enough to explain this to you i have to go back hello i'm jad album ron and i'm robert crow wins his radio lab
00:05:02barton to an earlier version of us because it was eleven years ago i think that we made a show called so called life life not as we know it oh god that show and in that show we dealt with an early sort of more primitive version with this
00:05:17very question so i'm just going to play you a few minutes of that of that earlier show well let's talk about life you and i will come back when you look around in the world of living things and i say look at there's a cat next that is
00:05:28a dog in that tree and you notice that those things of course are different Yes and later when we go to school we learned about file ums and categories like kingdoms and stuff something about the nature of those differences and then you're taught about struggle and competition don't
00:05:44are you and serve you 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 i'm steve strogatz i'm an applied mathematician at cornell and the story he told me which is based on analysis of
00:06:00dna and very tiny organisms mike girls is that once upon a time he says life began with a very primitive very simple collection of cells and these cells said steve the's sells it appears that you when you go back far enough there's a kind of rampant sharing of
00:06:19molecules it's a kind of orgy in which there are no well defined species or organisms and i can give you my genes you can pass were a communist i totally remember recording that the coon bio thinking that certain wheeler who was there at the start he produced this
00:06:37piece years ago yes i think it was just us around the office yeah it was a commune what what does that mean that it was a commune what do you mean what lying me i know what it means in the sixty screen love sense but what does it
00:06:48really mean what what sells air exchanging is chemicals chemicals that give them talents and trades jeans here's what happens I did this with steve in that are in our ancient puddle When darwin thought that life might have begun in a warm puddle let's say that you and i
00:07:02are both sell Okay so once upon a time there was you in a puddle and i'm in the same level as you 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
00:07:15You can handle cold water I'm shivering describe again what happens a tte this point in the glorious old days Well my membrane that is i am a cell I've got a membrane I've got my outer layer maybe a little bit porous and maybe what some of my genes
00:07:32just leaked okay We're not talking sophisticated organism and maybe your poorest too And you oh well you just absorb some of those genes So now we both have this we both got any book on If i've got this june now i can survive cold water because it's part
00:07:50of me and if i bump into you now it's part of you So now this steve jean has become a keen which has then become jack gene and were doing is over and run over and we're getting really communes it sends a friendly no actually they don't think
00:08:10of cells like people shut up all these exchanges this gene swapping was not intentional it's not purposeful sharing that's nigel golden fella i'm a theoretical physicist at the university of illinois and he and his colleague carl woese did the science that led to some of these kind of
00:08:26groovy idea it's not me sore saying hey i'm going to just help up my buddy over there here's a couple of genes that i think you'll find handy it's not something like that even still if we're swapping genes so much and you know you're giving me yours and
00:08:38i'm gonna be mine what does it actually mean to be me yeah if so much of me is spread around well would be very weird imagine a world in which for a while i have your nose god forbid on then i get my nose back you'd have steve's
00:08:53hair than steve would get my ear then he would get you are no since you're still having a lot of exchange i'll take your chin okay you could have my allergies and then you start even asking what does it mean to be a speech you can have my
00:09:08love affair with doubt you may not even be able to talk about individuals yeah if the mixing is good enough we're all kind of indistinguishable so identity would be very strange in this ancient world A lot of the close ups that we take for granted and biology become
00:09:26more and more nebulous as you get further and further back to the roots of the origin of life Take for instance charles darwin What nigel's really saying is that for the first billion years of life with being able to be everything that darwin teaches all that stuff hasn't
00:09:42happened to no borders no individuals There's no species That is darwinism Evolution as we now understand him that's an interlude in the real story of life it's on ly what's happening now What you got back at the very beginning was a whole bunch of cell slapping gene swapping
00:09:59advantages swapping disadvantages it's kind of a wild tremendous explosion of diversity in a way that life has not seen since then Until one dark and terrible day three billion years ago as interpreted by freeman dyson three the famous physicist and delivered here now their friend the mathematician steve
00:10:30struggles Here is sti one evil day A bacterium anticipating bill gates by three billion years refused to share Refused to share 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 found a way
00:10:53to keep my membrane from leaking That is i'm not going to be a sharing seoul anymore And why me What made that one little still decide to stop sharing that's A good question we don't really know but what we do know this's was maybe the most dramatic moment
00:11:08in the history of life on earth This transition from the age of well if you want to call it the age of sharing to the age of selfishness and gradually once one creature stop sharing pretty soon the others followed and then more and more to the same thing
00:11:24and now for the first time in the history of life finally we get darwin now we get species now we see differences yes it's the age of identity of individual ism it's also the age of of stasis things changed but they changed much more slowly and any great
00:11:40thing you know like you are a bad and you figured out sonar i don't have sonar i can't get sonar three nice to have sonar like you're in a little electric fish that lives in the muddy waters of the amazon you don't care it's totally dark you can
00:11:54see because you can see with electricity i can't see with electricity if i'm in the dark on bumping my head come on did we really use bill gates is standing for like selfishness yeah well i mean at the time he was the ultimate corporate it's horrible that we
00:12:12did that you know the state's foundation that's right sees actually gone over to the light side instead of the dark side right Exactly That is steve strogatz ended up calling him up just to chat him through some of this stuff and he told me that he actually heard
00:12:26this whole idea from a lecture by physicist freeman dyson dyson is just a great writer and a great speaker and he had this memorable line in their least memorable to me when he started talking about i mean he phrased the whole thing in terms of sharing which may
00:12:40be why in that previous episode we had that come by aussie singing's that wasn't my doing by the way no no that was it was us that but anyway so then he said but one evil day some primitive bacterium anticipating bill gates by three billion years refused to
00:12:56share its dna and then oh so that was that was freeman dyson that says yeah that was his joke so anyway was 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
00:13:08of the great microbiologists of our time and so you say you hadn't heard of karl was ahead before though i had not s o i the reason i was asking i think in the show we actually mentioned carlos because i remember it you know i don't know if
00:13:23you guys know there's not but so that was eleven years ago right I was actually an intern at the time i just showed up and i was tasked with tracking down carl woese who's the guy that we mentioned a sort of like the grandfather of this idea and
00:13:36he is like a huge huge deal in science hey discovered this whole other branch on the tree of life the r k o he's mr rk and which is a pretty big one is a whole nother wholenother kingdom of life it got him on the front page of
00:13:50the new york times and i had to track him down and turns out he was like the just the classic curmudgeonly scientists it took me twenty emails to get him to even like just let us talk to his collaborator nigel golden felt who we talked to in the
00:14:09show but whatever is a very strange he was a very curmudgeonly man but you know like he came to like me and i'd actually spend some time with him his office and we could do the curmudgeonly saying if i need teo you know we you get those skills
00:14:27yeah could we pass them curmudgeonly jokes back and forth and anyway ah after he heard the piece he wrote me the most sieving scathing email about and nothing there was nothing in it about like you got this wrong it was just like you made a cartoon of my
00:14:44work which honestly now listening back i agree with a little more than i did at the time yeah yeah but he was like i'm a serious person and you made this into like a dog and pony show and i was like i was brand new i was yeah
00:14:58and it hurt me like i was i felt really really bad he's like you've disrespected nigel and so i wrote i wrote i were called up steve maybe and said oh man you know this happened it and steve was like a listen forget them don't worry about it
00:15:15love steve yeah i don't know it sounds like something i might have said to you made you remember having that number i honestly don't remember having that conversation and that was like oh i needed that so bad at that moment my career for someone like with steve stature
00:15:28to like balance it out in that way yeah 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 or what we were trying to do i think our playfulness in
00:15:41an attempt to be clear and to communicate and to attract people who might not otherwise listen to a story about something called horizontal gene transfer he should have gotten that because he himself in his writing was very playful he was very fun to talk to i mean he
00:15:57was absolutely carlos was very playful and irascible and grouchy and charming but he would certainly tell you what he thought yeah yeah this this guy is a great character and david quammen it turns out in his new book talks a lot a lot a lot about carl woese
00:16:12and this revolution in our thinking about the evolution of life for the end of his life he started to think that he was more important and more profound than darwin He got a very negative attitude towards toward charles darwin darwin's birthday He'd said that he sent out a
00:16:27note that everybody had that this should be a day of rage That's right Yes yes he did that But well i guess i'm wondering is now that you spent a book's attention on him do you feel that he has some right to say that the picture we have
00:16:44of how life changes needs serious amending Or is he just barking because he's a barker 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
00:17:06earth What has happened all throughout the history of life on the planet for billion years and is still happening today This is where we are now the crazy details coming up right after the break This is young eun calling from a story in new york Radio lab is
00:17:40supported 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 Dot sloan dot or ge Hi i'm robert krulwich radio lab is supported by zip recruiter You know what's not smart job sites that
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00:18:34a b the mid term elections could make history because women are claiming a seat at the table The structures were built by and forge certain people and women weren't around the table when those structures were being built America maybe finally calling the question do white men still have
00:18:53a singular claim on real power In our politics I'm kai right Join us for the united states of anxiety gender power and the mid term elections A podcast from wnyc studios subscribed wherever you get your podcasts Chad robert radio lab and we're back with david common and this
00:19:13new due to us way of changing life infective heredity these leaping genes these transfers of dna that create new genetic possibilities in a blink turns out david told us that the swapping of genes but we talked about in the early history of life that's still happening today correct
00:19:36yes bacteria all around us those bugs are trading jeans jeans or jumping sideways from one kind of bacteria to another even in our belly is even in our guts so let's say that you go to france on a vacation and you touch something there and then you lick
00:19:56your finger i know you are or you eat something not new bacteria from that european fur is going into 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 yes what
00:20:11would that mean like physically like what it was like group out the cell wall and well they found that there were several different mechanisms for this too bacteria would create a little pipe a little sort of penis like thing between them and genes would be transferred but genes
00:20:28were moving sideways under other circumstances to from dead busted open bacteria into live bacteria is it acquired this new trait at once immediately immediately 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
00:20:53bacteria evolved these bugs they don't have to wait around for generation after generation to pick up random mutations are bacteria inside us can pick up a whole new abilities and new tricks pull it once from the air new neighbors so for instance one kind of bacteria could pass
00:21:09jeans for antibiotic resistance to another completely different kind of bacteria so say you've got somebody sitting in a hospital with a step flick caucus infection some of the bugs inside her have figured out how to resist penicillin when that bug then comes out of that human and it
00:21:28gets left on a table in a hospital and somebody else gets infected by it then they will also have an infection that is resistant to penicillin but if say they happen to be in the hospital sick with something totally different they have a different kind of harmful bacteria
00:21:43doing trouble giving them trouble and those old bacteria in them can learn in a flash from the new bacteria now everybody's penicillin resistant 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
00:22:02in the world health organization among others have called that 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
00:22:20the history of life understanding who we are quite literally because according to david the way we are the humans are has been affected by visits from other creatures jeans yes eight percent of the human genome is viral dna eight percent of the dna has come into humans or
00:22:41into our mammal ancestors sideways here's how that goes like you're sitting around and the 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 sellers
00:22:57prim so well then it will be passed along so we 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
00:23:13one of those creates a boundary layer between the human placenta and the fetus and absolutely necessary essential boundary layer now this is came as a total shock to me because after all the thing that's really special about mammals is that female mammals are at least placental mammals carry
00:23:34young around inside the body in the history of life this was a completely new development i mean do 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
00:23:46a creature that comes along and figures out how to keep the baby growing inside it question it does that has to make sure that it its immune system doesn't attack that baby and the baby has to be able to poop and stuff like that get things out so
00:23:59there has to be some kind of boundary and how did we get that good idea We got that good idea from a virus long long ago some ancient mammal ancestor got a virus got infected by a virus and that virus introduced a new gene the original virus it
00:24:13created an envelope a rapping 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
00:24:33products from the fetus to be carried away and disposed of by the mother i mean is this potentially the origin of mammals and with 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
00:24:51that that layer could not exist and does not function without this viral gene telling it what to do without this little bit of virus dna 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
00:25:16me and light of five years of studying and following it interviewing people about it the categories that we apply to the world categories like individual and species now appear more blurry Thie edges are fuzzy Is there such a thing as a human individual Or is a human a
00:25:40composite of other forms of life And what this says is that we're composites were most aix It's it's humbling and it's and it's Fascinating to think of yourself that way Like for me david So it turns out that david is not just the descendant of a norwegian father
00:26:00and a german irish mother but he's also viral and bacterial And who knows what else And i find that um i find it thrilling I'm grateful to all those other limbs on the tree of life for the things that they've given us Thanks of course to stephen strogatz
00:26:27of cornell university who was always willing to jump back into the pond where he long since had left and thought he'd gotten dried off from david commons New book is called the tangled tree and it's a gorgeous book so thanks to them And thanks to all of you
00:26:44for listening jack have ron i'm robert krulwich We'll see you next time Wait a second is that you buy on the sly version Could you snuck it in One single trojan horse with my name is that morning with me calling from mexico city radio live was created by
00:27:44jet abby run and it's produced by cern wheeler Dealing keefe is our director of sound design Maria matters are Padilla is our managing director Our stuff includes simon adler becca bressler rachel kazik david gable bethel hafta tracy hunt matt guilty robert cool which any maquis win Latif nasser
00:28:05melissa o'donnell syrian work ed walters and molly webster With help from shima Only i our fact checkers Michelle harris

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