Speaker 1: Welcome to Stuff to Blow your Mind from how Stuff
Speaker 1: Works dot com. Hey you welcome to Stuff to Blow
Speaker 1: your Mind. My name is Robert Lamb and I'm Joe McCormick.
Speaker 1: And boy do we have a treat for you today.
Speaker 1: That's right, we're we're chatting with Carl Zimmer about his
Speaker 1: new book, She Has Her Mother's Laugh, The Powers, Perversions
Speaker 1: and Potential of Heredity. This is a fantastic book. I
Speaker 1: I was trying to finish it before we talked to
Speaker 1: him today, and I was up till two am last
Speaker 1: night and getting to the very last page. But it
Speaker 1: was worth it. It is a great book. I really
Speaker 1: highly recommended. It's a brick that's just full of weird,
Speaker 1: interesting delights and insights about how our views of heredity
Speaker 1: have changed over the years, all of the good and
Speaker 1: all of the evil that that knowledge has been used for,
Speaker 1: and uh and also where it's going in the future. Yeah. Yeah,
Speaker 1: this it's a fascinating book. I also I got to
Speaker 1: see him in conversation with the Maria Knakova at World
Speaker 1: Science Festival this year, in which he talked about the
Speaker 1: themes in the book as well, so it was a
Speaker 1: real It's a real delight to have him here on
Speaker 1: the show. And if you want to check out She
Speaker 1: Has Her Mother's Laugh. It is available in hardback, digital
Speaker 1: and as an audio book. So, uh, we hope you
Speaker 1: enjoy our interview with him, but certainly go check out
Speaker 1: his book as well for just an in depth, riveting
Speaker 1: journey through heredity. Now, wait a minute, we should say
Speaker 1: who he is. I don't think we've done that if
Speaker 1: you're if you're not familiar with Carl Zimmer and Carl
Speaker 1: Carl Zimmer is a prolific, excellent science writer. He writes
Speaker 1: for the New York Times. I think I've also seen
Speaker 1: these articles in the Atlantic and National Geographic all over
Speaker 1: the place. Uh. He's written a lot about parasites and uh,
Speaker 1: some of the most interesting stuff in biology is is
Speaker 1: Karl's territory. And uh and I really had a good
Speaker 1: time talking to him today. Yeah. Some of his past
Speaker 1: books include Parasite, rex Evolution, The Triumph of an Idea,
Speaker 1: and Microcosm. So, without other ado, here's our conversation with
Speaker 1: Carl Zimmer. So, Carl, what led you to write a
Speaker 1: book about heredity? I guess in a way, I've been
Speaker 1: thinking about heredity for forever. Really. I mean, I when
Speaker 1: I was a kid, you know, I would uh think
Speaker 1: back on my ancestors that my parents told me about,
Speaker 1: and you know, I wonder, like, oh wow, if if
Speaker 1: you know, Roger Goodspeed had not sailed from England to
Speaker 1: Massachusetts in the sixteen thirties, would I ever exist? You know,
Speaker 1: those sorts of things. And then when I became a father,
Speaker 1: I've got two teenage girls now, and you know that
Speaker 1: immediately brought to bear just how urgent and mysterious heredity
Speaker 1: can be. Because now they're these two people walking around
Speaker 1: who have inherited a lot of my genes, and you
Speaker 1: know what, what is it that I'm giving them that
Speaker 1: that suddenly be the very pressing issue? And I guess
Speaker 1: what really then kind of crystallize it all for me
Speaker 1: was that in the past few years, I've been doing
Speaker 1: a lot of reporting from the New York Times and
Speaker 1: elsewhere about the real revolution happening in biology, allowing scientists
Speaker 1: to sequenced DNA, to rewrite DNA, and to also look
Speaker 1: at other kinds of biology that might help, uh create
Speaker 1: this thing that we call heredity. H And so it
Speaker 1: just it all kind of came together and I realized
Speaker 1: that this would be something that I really wanted to
Speaker 1: spend a couple of years really exploring deeply. So you
Speaker 1: mentioned the idea of the sort of personal curiosity about
Speaker 1: our ancestors, and you talk in the book about how
Speaker 1: we often do family genealogies to sort of learn something
Speaker 1: about ourselves, as if the seeds of who we are
Speaker 1: are somehow present in our really distant ancestors. But how
Speaker 1: many generations back do you have to go before those
Speaker 1: relationships with our ancestors really don't matter all that much
Speaker 1: in terms of genetic closeness. You know, you don't have
Speaker 1: to go back that far. And that just has to
Speaker 1: do with how parents passed down their DNA to their kids.
Speaker 1: You know, we each have two copies of each gene
Speaker 1: for the most part, but uh, you know, parents only
Speaker 1: passed down one copy of a given gene to each child,
Speaker 1: And so if you repeat that process generation after generation,
Speaker 1: there's a sort of a kind of a stochastic, kind
Speaker 1: of random process that will basically lead to you know, uh,
Speaker 1: some descendants not having any DNA at all from a
Speaker 1: particular ancestor. Um. There's only so much room in your
Speaker 1: genome and you can't pack in all the DNA from
Speaker 1: all your ancestors basically, and so geneticis have done some
Speaker 1: back of the envelope calculations and if you go back
Speaker 1: let's say ten generations, um, that would be like your
Speaker 1: ancestors in the sixteen hundreds. Uh, maybe only about half
Speaker 1: of them have a genetic link to you. The rest
Speaker 1: they're still your ancestors. But you cannot point to any
Speaker 1: piece of DNA in your genome and say, oh, I
Speaker 1: got that from from this particular person you know. So um,
Speaker 1: So I think that actually, like really shows how we
Speaker 1: have to, um think think bigger when it comes to heredity.
Speaker 1: It's not just some particular bit of DNA that that
Speaker 1: gives heredity its meaning. Well, on the other side of
Speaker 1: that coin, um, could you talk a little bit about
Speaker 1: what the Yale mathematician Joseph Chang discovered about human ancestry.
Speaker 1: It seems sort of like the flip side of what
Speaker 1: you're just talking about. Yeah, I mean, so, you know,
Speaker 1: so much about heredity is counterintuitive and almost you know,
Speaker 1: it seems to contradict itself, and that's in a way
Speaker 1: what makes it so fascinating. So I just told you
Speaker 1: about how if you go back a certain number of generations,
Speaker 1: you're gonna encounter their ancestors from whom you've inherited. No
Speaker 1: DNA at all. Um. But there's an interesting feature of
Speaker 1: human ancestry, which is that, um, you know, people uh,
Speaker 1: everybody today, Uh you know, it shares a common ancestor
Speaker 1: with some people who lived about five thousand years ago,
Speaker 1: roughly speaking in other words, UM, if you if you,
Speaker 1: it's just uh you can and you can figure this
Speaker 1: out as just Chang did, just by looking at genealogy
Speaker 1: is a mathematical problem. Um, just think of think of
Speaker 1: our genealogy is a kind of a branching network. Um.
Speaker 1: The thing is though that uh you know are if
Speaker 1: you think about your family tree, um, and you think, well,
Speaker 1: there's me, and then you branch off to your parents,
Speaker 1: and then they branch off to their parents and so
Speaker 1: on and so forth. Um. If you just keep branching
Speaker 1: in that simple way, you're gonna end, you know, a
Speaker 1: few thousand years back with more ancestors than there are
Speaker 1: people who have ever lived. You know, we're talking chillions
Speaker 1: of people. And that's absurd. So so that's actually not
Speaker 1: a realistic model of your ancestry. The fact is that
Speaker 1: your aunt all of you know, your parents are cousins
Speaker 1: now either that you know, in some cases first cousins
Speaker 1: get married, but in other cases they're very distant cousins.
Speaker 1: Another what that means is that your parents share an ancestor,
Speaker 1: a common ancestor somewhere in the past. It could be
Speaker 1: hundreds of thousands of years ago, but it doesn't matter.
Speaker 1: They have an ancestor. So what that does is it
Speaker 1: folds the family tree back in on itself. And what
Speaker 1: Joseph Chang realized was that that actually does something very
Speaker 1: interesting to human ancestry. What it means is that you
Speaker 1: do not have to go back very far to find
Speaker 1: somebody who is the common ancestor literally everyone on earth.
Speaker 1: Uh and uh, it's just in the past few thousand
Speaker 1: years that you could find people like that. Um. Now,
Speaker 1: of course you know those common ancestors, you know they
Speaker 1: for each of us that that's one person or a
Speaker 1: few people out of thousands upon thousands of ancestors. But
Speaker 1: it's something that ties us all together. And the irony
Speaker 1: is that you know, people are really uh uh really
Speaker 1: love to connect themselves to someone famous, you know, like, oh,
Speaker 1: did you know that I am descended from Lilliam the Conqueror.
Speaker 1: And the fact is that probably probably everybody of European
Speaker 1: descent is and is a descendant of William the Conqueror.
Speaker 1: Probably everybody of European descent is a descendant of Charlemagne Um.
Speaker 1: And you know, it's possible that everybody on earth is
Speaker 1: a descendant of you know, maybe Cleopatra. It's like, that's
Speaker 1: just the nature of human genealogy is that it's we're
Speaker 1: all descended from kings. That doesn't make anybody special. Well
Speaker 1: as as long as we're gazing backwards in time, here,
Speaker 1: can you tell us how ancient thinkers contemplated heredity? The
Speaker 1: weird thing is that they really didn't, and they at
Speaker 1: least they didn't think about heredity in the way that
Speaker 1: we do. Uh. You know that if you go back
Speaker 1: and you you look at what Hippocrates would say or
Speaker 1: Aristotle would say, Uh, this, this whole model of how
Speaker 1: we inherit something you know, microscopic and biological that that
Speaker 1: determines how we ended up the way we are just
Speaker 1: would not compute for them. And so you know, you know,
Speaker 1: someone like Aristotle would say, like, well, you know, the
Speaker 1: reason that one generation looks like the previous one is
Speaker 1: just because it's the same chemistry. Um, you know, of
Speaker 1: course you're going to be the uh, you're going to
Speaker 1: be the same because you know, it's the same set
Speaker 1: of processes that produced a person that produced you. So
Speaker 1: what's the big deal? And you know, the word heredity,
Speaker 1: you know, it's a very old word, but it only
Speaker 1: referred to basically inheriting stuff. Um, you know, and I'm
Speaker 1: talking not talking about jeans, I'm talking about houses. Uh,
Speaker 1: you know, farmland, things like that. You know, So in
Speaker 1: the Roman Empire, there are lots of rules about you know,
Speaker 1: who got to be an heir, and that's what the
Speaker 1: word meant at that point. And it's really fascinating, Like
Speaker 1: you have to you have to wait a long time
Speaker 1: before you start to even see the first glimmers of
Speaker 1: how we think about heredity today. Um. My favorite example
Speaker 1: is in the fifteen fifteen, around fifteen eighty, uh, Montana
Speaker 1: this this famous essays. He writes an essay about his
Speaker 1: father because Matennia now is is starting to get older
Speaker 1: and he's developing kidney stones, and it occurs to him
Speaker 1: that his father had kidney stones and around the same
Speaker 1: age and He basically writes Sussi saying, well, what is
Speaker 1: up with that? Now? Did I get these kids stones
Speaker 1: from my father? And like, if so, how because you know,
Speaker 1: when I was born, my father was young and he
Speaker 1: didn't have kidney stones, So what exactly went from him
Speaker 1: to me? Um? And you want to just you know,
Speaker 1: shout at the page like it's it's Janes, it's Jeans.
Speaker 1: But you know he can't hear you, you know, like
Speaker 1: he his question went fundamentally unanswered for centuries. Um And
Speaker 1: so yeah, so so uh, it's really need to look
Speaker 1: back and and see how. You know, the way we
Speaker 1: think is not how everyone always thought. You know, the
Speaker 1: way we think about heredity is is a product of
Speaker 1: really the modern age. So did the selective breeding of
Speaker 1: animals and plants inform classical and medieval thinkers at all
Speaker 1: about the possible nature of heredity, because it seems it's
Speaker 1: I mean, it's kind of seems like people such as
Speaker 1: Aristotle or Albertus Magnus would have would have looked at
Speaker 1: how we bred flowers, crops and farm animals more were,
Speaker 1: at least in addition to the influence of geography or experience,
Speaker 1: you would think, so I would I would have thought so.
Speaker 1: But I think that's because we are in the century
Speaker 1: and we look back and say, well, everyone must have
Speaker 1: thought the way we did. But there are actually, you know,
Speaker 1: whole books written, uh you know by Roman writers about
Speaker 1: farming for example, UM, and you can search them as
Speaker 1: I mean, I have sat down and look through these
Speaker 1: books for anything resembling what you're talking about, and it's
Speaker 1: just not there. They do not talk about, oh, well,
Speaker 1: there's some you know quality in this particular variety of
Speaker 1: olives that you know, if you if you if you
Speaker 1: bread it, it will pass it down to two future
Speaker 1: generations of olive trees. That this isn't there. Instead, they'll
Speaker 1: say like, well, make sure that you know you're you're
Speaker 1: growing it on good soil, make sure your your farm
Speaker 1: gets a good supply rain. It's all about the environment.
Speaker 1: And it isn't really until I would argue, it's not
Speaker 1: really until the seventeen hundreds that uh, you start to
Speaker 1: see these farmers, these livestock breeders really take interest in this, UM.
Speaker 1: And part of it is that these European countries are
Speaker 1: all um looking for ways to use science to uh
Speaker 1: make their countries wealthier. And you know, they're thinking, well,
Speaker 1: if we can, we can, if we can produce new
Speaker 1: varieties of animals implants, um, then we we will enrich ourselves. Uh.
Speaker 1: And there's this one breeder named Robert Bakewell who produces
Speaker 1: an entirely new breed of sheep just by starting to
Speaker 1: think about heredity, to think about which individuals those sheep
Speaker 1: is he gonna mate together? Is he gonna just only
Speaker 1: mate within his flock? Is he gonna go pick out
Speaker 1: other ones from other flocks to mate? Um? And lo
Speaker 1: and behold he produces this this very successful new breed.
Speaker 1: And you know, people like Charles Darwin look at that
Speaker 1: and say, what just happened? How did they do that? Um?
Speaker 1: And in Germany and in Central Europe there's a big
Speaker 1: push to do the same thing with sheep, to do
Speaker 1: that with crops as well, and uh and to try
Speaker 1: to understand what are these rules. And one of those
Speaker 1: people who's trying to understand those rules is none other
Speaker 1: than Gregor mendel Um. So his his breeding experiments, you know,
Speaker 1: the foundation of genetics comes out of this new push
Speaker 1: to try to use heredity to enrich nations. All Right,
Speaker 1: we're gonna take a quick break and then we're gonna
Speaker 1: jump right back into the interview and we're back. So
Speaker 1: at what point does the modern idea of heredity really emerge. Well,
Speaker 1: I'd say in the late eighteen hundreds, UM, people start
Speaker 1: to talk about heredity as a scientific question. And Charles
Speaker 1: Darwin is really important in all of this because, you know,
Speaker 1: he he comes up with the theory of evolution and
Speaker 1: it depends on heredity. In other words, Um, you know,
Speaker 1: the only way for natural selection to work is so
Speaker 1: if parents can pass down traits to their offspring to
Speaker 1: give them some advantage and surviving and reproducing. And so
Speaker 1: it's very obvious to Darwin that, you know that that
Speaker 1: heredity is this huge glaring question in the middle of
Speaker 1: his theory, and he and he works really hard to
Speaker 1: try to find out for himself how heredity works. And
Speaker 1: he's he's very aware of a lot of the research
Speaker 1: that's going on at the time, looking to the discovery
Speaker 1: of cells and the discovery that there are little things
Speaker 1: inside of cells, but no one's quite sure what they are. UM.
Speaker 1: And so he develops a theory that there are particles
Speaker 1: in the cells throughout our body that they somehow stream
Speaker 1: into the eggs and sperm and uh then become something
Speaker 1: like we the way we think of genes um. That
Speaker 1: doesn't pan out. You know, his cousin, Francis Galton, tries
Speaker 1: to test it by injecting blood from uh, you know,
Speaker 1: black rabbits into white rabbits, you know, different colored rabbits,
Speaker 1: and seeing if that changes the color of their offspring.
Speaker 1: Doesn't happen. Uh and uh So it's not really until
Speaker 1: after Darwin is dead that scientists start to really understand
Speaker 1: chromosomes and then rediscover mental and it all clicks together,
Speaker 1: and the science that they that they call genetics is
Speaker 1: born in nine uh and and you know, the it's
Speaker 1: really you can see how exciting it is for the
Speaker 1: scientists at the time. William Bateson, who coined the term genetics.
Speaker 1: He he writes at the time that you know, the
Speaker 1: science of heredity has been red illuctionized. You know that
Speaker 1: finally they feel like they can they can understand heredity
Speaker 1: um in its fundamental basis. So so how do we
Speaker 1: go from this point of of of just excitement and
Speaker 1: discovery and just fall so steeply into eugenics and then
Speaker 1: ultimately the horrors of the third Reich well, if you
Speaker 1: look back, the roots of eugenics UM go back pretty far. UM.
Speaker 1: You know. So Uh. On the one hand, uh, so
Speaker 1: our modern conception of race uh starts to develop as
Speaker 1: early as really the fifteen hundreds are the fourteen hundreds,
Speaker 1: even where in Spain, UH, Jews are are being considered
Speaker 1: a separate race of people, and and and noble families
Speaker 1: have to do have to draw out genealogies to prove
Speaker 1: that they don't have any Jews in their in their ancestry. Um.
Speaker 1: Other wise they you know, they won't be able to
Speaker 1: get that good job in government or so on. And
Speaker 1: so that starts to develop this idea that that groups
Speaker 1: of people are fundamentally different in some way that is
Speaker 1: carried on from one generation to the next. Um. Then uh,
Speaker 1: in the in the eighteen hundreds, you start to see,
Speaker 1: you know, a real concern about UM poverty and crime
Speaker 1: and and a lot of people start to to make
Speaker 1: claims that these are being carried down in certain families.
Speaker 1: You know, there are these bad families and why is
Speaker 1: it that one generation is just as bad as the
Speaker 1: previous one. And you know, people talk about some sort
Speaker 1: of hereditary curse that they must have and and then
Speaker 1: you know, how do we keep that curse from being propagated.
Speaker 1: And so then when genetics gets discovered, UM, a lot
Speaker 1: of actual genesis themselves and uh and other and others
Speaker 1: say well, aha, like here's here's the basis for what
Speaker 1: we've been talking about for decades now. UM. And you know,
Speaker 1: the word eugenics had actually been coined in eighteen eighties
Speaker 1: by Francis Coulton, Uh, Darwin's cousin, and he just thought, well,
Speaker 1: you know, if intelligence is inherited, then why don't we
Speaker 1: just essentially breed people away we breed sheep, So you
Speaker 1: just pick out the individuals who seemed to have you know,
Speaker 1: the most genius he would call it, and then encourage
Speaker 1: them to have lots of kids. And and he had
Speaker 1: these dreams that to produced what he called the galaxy
Speaker 1: of genius in the future. UM. But by the time
Speaker 1: that eugenics arrives in the United States and genetics emerges,
Speaker 1: it takes on a much darker cast because people say, well,
Speaker 1: what we really need to focus on is these people
Speaker 1: who have who we believe have genes that we don't like,
Speaker 1: and we want to prevent them from reproducing, because that's
Speaker 1: going to drag down our country, and so what are
Speaker 1: we to keep them from reproducing? And um that leads
Speaker 1: to sterilization and much worse. So in reading your chapter
Speaker 1: about Henry Goddard and the origins of the American eugenics movement,
Speaker 1: I'm struck that this is a potential example of the
Speaker 1: dangers of bad research, Like you draw a really disturbing
Speaker 1: picture of how but like sloppy or fraudulent work that
Speaker 1: became the basis of Henry Goddard's published writings on heredity
Speaker 1: can be viewed in some ways is contributing directly to
Speaker 1: real world consequences, like the horrors of for sterilization in
Speaker 1: the United States or mass murder in Europe. Do you
Speaker 1: ever think, when you see bad science or pseudoscience being
Speaker 1: being publicized today that it could ever lead to such
Speaker 1: nightmares that even its authors might not have imagined? Uh,
Speaker 1: you know, I don't. I think that we can't rule
Speaker 1: out those kinds of possibilities. I mean, it might be very,
Speaker 1: very unlikely, But if you look at history, you can
Speaker 1: see how bad science combined with existing prejudices lead to
Speaker 1: really horrific outcomes. And it wasn't that the science was
Speaker 1: somehow appropriated by the pseudo scientists or something. Uh. Eugenics
Speaker 1: was embraced by most of the leading um biologists of
Speaker 1: the time. UH and Uh, there were different forms of eugenics,
Speaker 1: you know. So some people were very much sort of concerned,
Speaker 1: were quite racist and you know, concerned about uh, you know,
Speaker 1: the white quote unquote race being you know, polluted by
Speaker 1: other races. Um. But then there were progressives who thought
Speaker 1: that this was going to be part of their grand
Speaker 1: plan for making society a better, fairer place. Um. And
Speaker 1: I think it's really important to look at these episodes
Speaker 1: in history to see how things go bad. Um. And
Speaker 1: I think it's I think it's arrogant for any of
Speaker 1: us to say, well, things like this could never happen again,
Speaker 1: you know, and somehow we're vaccinated from from these sorts
Speaker 1: of things. But we can draw lessons from the past,
Speaker 1: and we can see how, um, how humble we need
Speaker 1: to be in the face of complexity in in our
Speaker 1: own biology. You know. We you know, I think we're
Speaker 1: in like in another revolution, the way we were hundred
Speaker 1: years ago. You know, a hundred years ago, genetics itself
Speaker 1: was profoundly new, that gene was a new thing. Uh.
Speaker 1: Now we're at the point where we're looking at genomes,
Speaker 1: in other words, all the genes in our in our selves,
Speaker 1: and we can we can see them down to the
Speaker 1: atomic detail. Um, but there's still a vast amount we
Speaker 1: do not understand about it, and UM, you know, we
Speaker 1: we cannot let that be an opportunity to you. Uh
Speaker 1: you know, card out our old biases and prejudices and say, oh,
Speaker 1: I see now science backs up what I was saying
Speaker 1: all along about those other people. UM, we can't. We
Speaker 1: just we cannot let that happen. Again. I think that's
Speaker 1: a really good point. And I also think you can
Speaker 1: even look at it as there's a flip side to
Speaker 1: it where modern discoveries of genomics really complicated or in
Speaker 1: some sense is undermine what many people have traditionally understood
Speaker 1: as the concept of race within humans. Right. Yeah, So
Speaker 1: the scientific concept of race uh developed in the in
Speaker 1: the seventeen hundreds, and it was really um, very much
Speaker 1: spurred on by, uh by what Europe was doing at
Speaker 1: the time. So Europe was in the midst of building
Speaker 1: up huge colonies um and enslaving many many people. There
Speaker 1: was a need for serve legal and moral justifications for
Speaker 1: doing this, and a lot of it, uh was based
Speaker 1: on these concepts of race, so that for example, you know,
Speaker 1: Africans were were claimed to be a completely separate race
Speaker 1: uh that you know, had inherent uh inferiority to the
Speaker 1: white race. And so therefore slavery is okay. And you
Speaker 1: can see this again and again in in lots of
Speaker 1: lots of writing at the time. Uh. Now, even in
Speaker 1: the early nineteen hundreds, Um, there were there were indications
Speaker 1: that this kind that genetics was not aligning with these
Speaker 1: these uh old ideas about race, and they just weren't
Speaker 1: fitting neatly. Um. You it was very it was it
Speaker 1: was becoming harder and harder to draw any particularly bright
Speaker 1: line between groups of people. I mean, obviously people are different, uh.
Speaker 1: You know, there are lots of differences and people in
Speaker 1: terms of skin color and height and shapes of faces
Speaker 1: and culture and all the rest of it. But the
Speaker 1: genes were not supporting these old ideas about race. And
Speaker 1: by the midnighteteen hundreds of people, a lot of anthropologists
Speaker 1: and geneticisis were saying, you know, the word race is
Speaker 1: so burdened with so much that's terrible and immoral and
Speaker 1: has so little connection with the way we're starting to
Speaker 1: understand populations. Let's just get abandoned it. Um, that really
Speaker 1: hasn't that really didn't happen. But nevertheless, like now where
Speaker 1: we can look at the whole genomes. Um. Yeah, the
Speaker 1: whole thing with race now is is it just is
Speaker 1: it's a bit one. The way one genete has put
Speaker 1: it to me is like, well, you know, like talking
Speaker 1: for us, like talking about race is like the way
Speaker 1: Greeks talked about the you know, the four elements air, fire, water, earth,
Speaker 1: like you know it. You know, Aristotle could explain all
Speaker 1: sorts of things uh that way, and they seemed good
Speaker 1: to him. But you know, we know that there's things
Speaker 1: are much more complex than the four elements, and if
Speaker 1: you forced physicists to go back to the four elements,
Speaker 1: they'd be very unhappy. So Jenets they're saying like, please
Speaker 1: don't make us go back to you know, the genetic
Speaker 1: equivalent of the four elements. You know, we're you know,
Speaker 1: they're very interested in ancestry and how populations mixed together,
Speaker 1: how they become isolated, and all the rest of it.
Speaker 1: But these old ideas about race and on all the
Speaker 1: connotations of race they don't map onto it at all,
Speaker 1: so they just don't want to use it now. Of course,
Speaker 1: in addition to just the passing on of genetic information, UH,
Speaker 1: we also have epigenetics. And even as you explore the
Speaker 1: effects of the microbiome, can can you talk about how
Speaker 1: these have changed our definition of heredity? So in the
Speaker 1: eight hundreds, heredity becomes a scientific question. You know, what
Speaker 1: is it that makes one generation connected to the past?
Speaker 1: Why is it that generations resemble their forerunners? Um? What
Speaker 1: what are these connections? And Uh, genetics provided a huge
Speaker 1: part of that answer, which is that well, genes get
Speaker 1: copied and then transmitted through eggs and sperm and uh.
Speaker 1: And so that was a huge revolution and understanding. But
Speaker 1: that doesn't mean that that is all that heredity can be.
Speaker 1: I mean there's still the at least the logical possibility
Speaker 1: that there are other ways that each generation be can
Speaker 1: be connected to the to the previous ones. And so
Speaker 1: in my book I talk about different forms of heredity
Speaker 1: that scientists are exploring. UM and so you know, one
Speaker 1: one very exciting possibility is what you referred to as epigenetics.
Speaker 1: And epigenetics is kind of a broad term, but roughly speaking,
Speaker 1: what it refers to is the molecules inside our cells
Speaker 1: that control our genes. That that allows some genes to
Speaker 1: be switched on and to produce proteins and others that
Speaker 1: are kept silent um. And you know, it's it's very
Speaker 1: clear that this is incredibly important to our existence. You know,
Speaker 1: it's what makes your skin cells be skin cells, and
Speaker 1: you're you know, brain cells be brain cells, like they
Speaker 1: are using different genes in the same genome. And when
Speaker 1: these cells divide um the you know, a skin cell
Speaker 1: does not normally instantly become a neuron or or you
Speaker 1: know it doesn't you don't grow a tooth on your
Speaker 1: back of your hand um. And that has to do
Speaker 1: with epigenetics um. And so what does this have to
Speaker 1: do with heredity. Well, you know, when those cells divide,
Speaker 1: they are basically inheriting the genes and the epigenetics of
Speaker 1: their mother cell. But you know that the possibility arises, well,
Speaker 1: what if you pass those down to the next general
Speaker 1: ation altogether, you know, through eggs and sperm um. And
Speaker 1: there's some evidence that that that can happen. And what
Speaker 1: makes it especially exciting is that you know, through our lives,
Speaker 1: experiences can change the epigenetic makeup of ourselves. You know,
Speaker 1: so if you if you get sick, if you smoke,
Speaker 1: if you experience stress, those all seem to have an influence.
Speaker 1: And so the open question is, well, how much can
Speaker 1: those experiences we have in our lives then influence future generations? UM.
Speaker 1: I think that the jury is still very much out
Speaker 1: when it comes to people. UM, But in other species,
Speaker 1: especially plants, there's lots of evidence that that really is
Speaker 1: something that happens. You know, a plant goes through a
Speaker 1: drought and generations later there's still an epigenetic mark on
Speaker 1: its descendants. So yeah, epigenetics is in a really exciting area.
Speaker 1: So you just alluded to some of the controversy about epigenetics,
Speaker 1: and I guess there are other forms of ideas of
Speaker 1: non genetic inheritance, but epigenetics in some ways still remains controversial,
Speaker 1: especially in humans. Like you're talking about, if you're comfortable
Speaker 1: speculating and if you had to guess, how would you
Speaker 1: imagine our picture of non genetic inheritance might change over
Speaker 1: the next fifty years or so, what's your sense? You know,
Speaker 1: I think that it is actually possible that we'll just
Speaker 1: find that UM. Human epigenetics is just not really that important.
Speaker 1: I mean, I'm actually I think there's reason to be
Speaker 1: kind of pessimistic. Um that you know, there are these
Speaker 1: very cantalizing studies, but they're small and they could just
Speaker 1: be the result of noise and so on, and and
Speaker 1: yet you know, we really want epigenetics to be real. Um.
Speaker 1: I mean, epigenetics has totally taken hold of the popular consciousness.
Speaker 1: And you know, I was astonished to learn not long
Speaker 1: ago that you can take classes and epigenetic yoga, which
Speaker 1: not kidding, you can google it. And the thinking is,
Speaker 1: the claim is that you know that by doing this
Speaker 1: yoga you change the epigenetic profile of yourselves and I
Speaker 1: and you know there are psych psychiatrists who will offer
Speaker 1: you epigenetic analysis to basically undo the trauma that you
Speaker 1: inherited from past generations. Um. It really speaks to us
Speaker 1: in a very profound way. But I actually don't think
Speaker 1: that science is going to really hold up very well. Um,
Speaker 1: because are but I don't think it looks like our
Speaker 1: biology just doesn't really allow that to make much of
Speaker 1: a difference. But you know, the flip side is that culture,
Speaker 1: um is actually I I would argue an incredibly important
Speaker 1: form of fredity, especially for our species. We we pass
Speaker 1: down not just our genes to the next generation, but
Speaker 1: all of our knowledge and and beliefs and customs and
Speaker 1: so on, and those those get pell down through the
Speaker 1: generations UM in a very hereditary way and UM, and
Speaker 1: that's actually very different from other species. And I would
Speaker 1: and you know, in the book, I talked about how
Speaker 1: you could argue that civilization itself is the product of
Speaker 1: our very special form of cultural inheritance. So in talking
Speaker 1: about non genetic inheritance, you've got potentially epigenetics, though the
Speaker 1: juries out on that, You've got, you've got culture. But
Speaker 1: we should talk a little bit about microbiology. Can you
Speaker 1: tell the story of how you found out that your
Speaker 1: belly button contained bacteria only known to exist in the
Speaker 1: Mariana Trench? Absolutely? Yeah. So I've been incredibly fascinated by
Speaker 1: the microbiome, you know, all the bacteria that live on
Speaker 1: us and in us for quite some time and and
Speaker 1: I have been doing some reporting on it as scientists
Speaker 1: have found new ways to to explore our microbiome. And
Speaker 1: it used to be that you just have to scrape,
Speaker 1: you know some you know a little bit of skin,
Speaker 1: or take a stool sample and taken into a lab
Speaker 1: and try to grow bacteria. And the fact is that
Speaker 1: very few of the bacteria that live on us uh
Speaker 1: or in US enjoy being in a petri dish on
Speaker 1: their own. It just it makes them miserable and they
Speaker 1: don't grow. So we had a very impoverished view of
Speaker 1: this inner world until scientists were able to just say, Okay,
Speaker 1: we're going to grow into this sample and just grab
Speaker 1: out all the DNA and we're gonna sequence all the
Speaker 1: DNA and from that we're going to figure out what
Speaker 1: is in there. And that totally revolution. I studied the
Speaker 1: microbiome because now you didn't have to grow these critters.
Speaker 1: You could just fish out their DNA and look at that.
Speaker 1: So it turns out we have hundreds, maybe thousands of
Speaker 1: species in our guts and on our skin and so
Speaker 1: on and um and so you know, one day at
Speaker 1: a meeting, UM I was walking past a scientist who
Speaker 1: was holding out a qute tip and he said, I'm
Speaker 1: doing a study on people's belly buttons. Would you mind
Speaker 1: giving me some of your belly button lint? Belly button lint,
Speaker 1: and I want to see what's in there, you know,
Speaker 1: and for someone like me, you don't have to ask
Speaker 1: me twice. I'm like, give me that cute tip. So
Speaker 1: you know, I go off into the bathroom and I
Speaker 1: you know, fiddle around and don't get in a little
Speaker 1: tube that they gave me and handed it back, and
Speaker 1: then they went off and they looked at all the
Speaker 1: DNA there was on that cute tip, and you know,
Speaker 1: a lot of it was my own skin cells, but
Speaker 1: then a whole lot of it was not um. And
Speaker 1: actually they identified fifty three species as I recall of
Speaker 1: bacteria just in my belly button, and uh, it was
Speaker 1: amazing to to look at, uh, the information about each
Speaker 1: of those species. And so one of them it's had
Speaker 1: only there's only no own from a sample at the
Speaker 1: bottom of the ocean. They marry on a trench um.
Speaker 1: And there's another one that I have that's only been
Speaker 1: found in soil in Japan. I've never been to Japan,
Speaker 1: so um. But you know, this was entirely unsurprising to
Speaker 1: this scientist, because you know, he was looking at lots
Speaker 1: of people and was finding people with you know, over
Speaker 1: a hundred species just in their belly button alone, and
Speaker 1: from all sorts of different places. Um. So what does
Speaker 1: this have to do with heredity? Well, you know, I
Speaker 1: I did not inherit that marry on a trench bacteria
Speaker 1: from my parents. UM. It's just you know, we have
Speaker 1: all of this, these these bacteria in the environment um,
Speaker 1: and some of them have become very well adapted to
Speaker 1: living on our bodies. Um, and we just picked them
Speaker 1: up um through our life. But it does seem like
Speaker 1: that the microbiome UM, that there is some heredity to it. UM.
Speaker 1: The best examples come from certain animals like that passed
Speaker 1: down bacteria to their offspring. Then these bacteria can only
Speaker 1: live inside these animals, and without those bacteria, these animals die.
Speaker 1: The cockroaches are actually a great example of this. So
Speaker 1: you know, one reason that cockroaches are so successful is
Speaker 1: because they harbor one species of bacteria in a special
Speaker 1: little organ um where it breaks down some of their
Speaker 1: food and gives them nutrients. Um. And these bacteria never
Speaker 1: live outside of the cockroaches, and actually they're they're sitting
Speaker 1: inside of cockroach cells. And then in the female cockroaches,
Speaker 1: those cells crawl over to an egg and rip open,
Speaker 1: and then the bacteria infect the eggs so that cockroaches
Speaker 1: are born completely infected with these bacteria. That's that to
Speaker 1: me just seems that's heredity. I mean, these bacteria are
Speaker 1: being passed down from millions of years from parents to offspring.
Speaker 1: Um so the US and now as well. Are is
Speaker 1: that true for humans? Um? Maybe not, uh, you know,
Speaker 1: in that particular way, but um, you know, it is
Speaker 1: possible that there are a lot of species that are
Speaker 1: very much adapted to us. You know, maybe mothers are
Speaker 1: passing down certain kinds of bacteria in the birth canal
Speaker 1: or during breastfeeding. Um. And maybe the most dramatic example
Speaker 1: of all is that in all of ourselves we generate
Speaker 1: fuel with these little blobs called mitochondria, which have their
Speaker 1: own DNA in them. And the reason they have their
Speaker 1: own DNA is because they started out as bacteria and
Speaker 1: about two billion years ago and our single celled ancestors,
Speaker 1: those bacteria infected our ancestors and then took up permanent
Speaker 1: residence in there and we cannot live without them today.
Speaker 1: So um so, so MicroB is gonna have a very
Speaker 1: powerful part in heredity. Do you think our expanding consciousness
Speaker 1: about the full scope of heredity from like generation into
Speaker 1: symbiance or even to camerism should force us to re
Speaker 1: examine our ideas about what it means to be an individual,
Speaker 1: an individual animal, and what the biological and categorical boundaries
Speaker 1: of the self really are. Absolutely, uh, you know, I
Speaker 1: think that uh, you know, heredity does not actually follow
Speaker 1: a lot of the simple rules that we assume. It does, uh,
Speaker 1: and it and it does bring into question what it
Speaker 1: means to be an individual because you know, we think
Speaker 1: of he started out with some original genome in a
Speaker 1: fertilized egg, so we inherited half of that genome for
Speaker 1: me to our parents. It came together in this new
Speaker 1: combination and that's us. But you know that is not
Speaker 1: actually us um, and in lots of different ways. So
Speaker 1: in one way, I mean, if you actually follow the
Speaker 1: cells that divide in an embryo, those cells can mutate
Speaker 1: and then utate again and mutate again, so that if
Speaker 1: you were to look at, say, any two neurons in
Speaker 1: your brain, they would be different from each other because
Speaker 1: they have acquired different mutations as we developed. UM. So
Speaker 1: there is no one genome in our body because we
Speaker 1: are what scientists say call us our mosaics. UM. But
Speaker 1: then that's not the not the end of it. UM.
Speaker 1: So you know, we think of heredity is going down
Speaker 1: through the generations, but heredity can also come back up
Speaker 1: in reverse. Uh. And so one example of this is
Speaker 1: um when women become pregnant, UH, cells from their fetus
Speaker 1: will circulate around in their blood. You can actually you
Speaker 1: can actually draw blood from a pre new woman and
Speaker 1: sequence the genome of the fetus. Uh we that is
Speaker 1: done on a regular basis. Now uh after pregnancy, uh,
Speaker 1: those fetal cells may go away because of the mother's
Speaker 1: immune system is clearing them out. But surprisingly often uh
Speaker 1: those cells can establish themselves in a mother's liver, syroid, gland,
Speaker 1: even her brain. And scientists refer to uh such people
Speaker 1: as chimeras. Um it's after the you know, the beast
Speaker 1: of Greek mythology. And you can get chimeras also from
Speaker 1: twins in the womb who are sharing DNA sharing cells uh.
Speaker 1: And so you can literally like have um. You know
Speaker 1: that one of the first discoveries of this was a
Speaker 1: woman who gave blood in the nineteen fifties and totally
Speaker 1: baffled uh the blood bank because she was giving two
Speaker 1: types of blood at the same time. And he said,
Speaker 1: this is not possible, you know, there must be some
Speaker 1: contamination somewhere. But it turned out that her blood was
Speaker 1: made up from two individuals, herself and a twin who
Speaker 1: had died when he was in infancy. Uh. And so
Speaker 1: you know, and this is not something that's rare. Timerism
Speaker 1: is probably quite common among humans, and it really challenges
Speaker 1: these these ideas that we we tell ourselves about heredity
Speaker 1: and individuality. One of the weirdest and most interesting types
Speaker 1: of heredity you discussed in the book is that, I
Speaker 1: think you said of it's eight or so lines of
Speaker 1: contagious cancer found in nature so far. Can you talk
Speaker 1: a little bit about contagious cancer and does it make
Speaker 1: sense to think of this cancer as an independent animal
Speaker 1: or organism of its own type, or as sort of
Speaker 1: an infection from an original animals genome. Yeah, this is
Speaker 1: where heredity gets really weird because us, you know, when
Speaker 1: when cancer arises in our bodies, it's a it's another
Speaker 1: one of these cases of mosaicism. In other words, Uh,
Speaker 1: these cancer cells are gaining mutations that the rest of
Speaker 1: the body doesn't have, and those mutations allows them to
Speaker 1: reproduce quickly and to be very aggressive and destructive. Now, Um,
Speaker 1: cancer usually uh, you know, either is wiped out by
Speaker 1: the body or is lethal. In either case, you don't
Speaker 1: have cancer surviving beyond the life of its host. We
Speaker 1: we think of that as being weird, but it turns
Speaker 1: out that in fact cancer can endure um And this
Speaker 1: was really first discovered um in in a uh in
Speaker 1: a case with dogs where dogs would be uh developing
Speaker 1: um these these tumors uh. And it was very odd
Speaker 1: that they the cancer seemed to spread like an infectious disease,
Speaker 1: and so people scratching their head over this, and then
Speaker 1: they realized that actually what had happened was that the
Speaker 1: cancer cells themselves were spreading from one dog to another
Speaker 1: to another UM and so that the cancer cells were
Speaker 1: not in fact related to the dogs that they were in.
Speaker 1: And if you look at the DNA of this cancer,
Speaker 1: it goes back to some dog that lived maybe ten
Speaker 1: thousand years ago, and it has just been spreading from
Speaker 1: dog to dog ever since, and it's been mutating along
Speaker 1: the way. And it's and so it's the thing that
Speaker 1: you know, it's it's what do you call it? I mean,
Speaker 1: I don't know what we could call it, but you know,
Speaker 1: some have argued that it should be just given its
Speaker 1: own species name because it's it's this, it's this lineage
Speaker 1: of animal cells that has its own genome UM, and
Speaker 1: has its own way of getting around in the world.
Speaker 1: It's it's doing just fine. UM. So surely it deserves
Speaker 1: the name UM. And then it turns out that in
Speaker 1: a few other cases scientists have found another species, so
Speaker 1: Tasmanian devils in Tasmania, they get a facial tumor because
Speaker 1: they bite each other when they're fighting, and they spread
Speaker 1: this cancer to each other. UM. And this this cancer
Speaker 1: has actually arisen a couple of times in Tasmania just
Speaker 1: in recent decades, so it isn't something that only happened
Speaker 1: once a long time ago. And what's most mind blowing
Speaker 1: is that some scientists stumbles across this yet again, just
Speaker 1: in the past few years uh in clams, in shellfish UH,
Speaker 1: and have discovered that there there's contagious cancer in the ocean. UM.
Speaker 1: So you're swimming. As you're swimming in the ocean, you're
Speaker 1: swimming around cancer cells that are moving from host to host.
Speaker 1: An infectious cancer as its own type of organism. What
Speaker 1: kingdom of life would that be? Would it be an animal? I? Yes,
Speaker 1: it would be an animal simply because it's descended from animals. Yeah,
Speaker 1: I mean I would say they would have to be given,
Speaker 1: you know, a place in the animal kingdom. But and
Speaker 1: you know, maybe you should just still call it like
Speaker 1: a species of you know, maybe the dog cancer should
Speaker 1: be a species of dog. Maybe you know, cana is
Speaker 1: cancer or something. I don't know. I don't know, um,
Speaker 1: but you know it's and you know, when when and
Speaker 1: when you talk about or what makes up an animal,
Speaker 1: you know, like, uh, what makes up up us? You know,
Speaker 1: like we think of cancer cells as being part of ourselves.
Speaker 1: They they originate from our own selves. But um, imagine
Speaker 1: if your body was actually made up of your own
Speaker 1: cells and then cells that came from someone ten thousand
Speaker 1: years ago, that that would be weird. Yeah, alright, time
Speaker 1: for a quick break. Then we will be right back
Speaker 1: for more of our versation with Carl zimmer Than. All right,
Speaker 1: we're back now. We can't talk about the future of
Speaker 1: heredity without touching on Crisper. How is this technology affecting
Speaker 1: the future of human redity? Well, you know, we're going
Speaker 1: to have to wait and see exactly what happens, but
Speaker 1: certainly the potential is profound um. Crisper is just a
Speaker 1: few years old, and it's this is this technology essentially
Speaker 1: to zero in on any particular bit of DNA, cut
Speaker 1: it out, and if you want, insert a different little
Speaker 1: stretch of DNA in there. So um, this raises the
Speaker 1: possibility of being able to cure hereditary diseases by rewriting uh,
Speaker 1: the DNA in cells, you know, to repair a faulty gene.
Speaker 1: But what some scientists have been already exploring is, well,
Speaker 1: what if you take human embryonic cells. What if you
Speaker 1: take you know, human embryos are just a tiny little
Speaker 1: cluster just you know, seven or eight cells, and you
Speaker 1: use Crisper to rewrite their DNA. UM, let's say you
Speaker 1: fix a hereditary disease in just this handful of just
Speaker 1: as few cells. Well that if if you if that
Speaker 1: if a person were to develop from those cells, they
Speaker 1: they would have Crisper altered genes throughout their whole body,
Speaker 1: and if they were to have children, they would pass
Speaker 1: on those Crisper altered genes as well. And so you
Speaker 1: know that that that these experiments have already begun on
Speaker 1: on these tiny little human embryos, and so really, you
Speaker 1: know what what needs to happen now is for us
Speaker 1: to have a really a kind of global conversation about
Speaker 1: whether we want to use this or not, whether it's safe,
Speaker 1: whether it's ethical. UM, how do we feel about who
Speaker 1: should have access to this? UM? Do we have the
Speaker 1: right to alter future generations? Um? And you know we
Speaker 1: and maybe we'll feel comfortable with, say, you know, eradicating
Speaker 1: Huntings disease. But what if somebody says, well, yeah, but
Speaker 1: I want I'm using IVF and I want to just
Speaker 1: give my kids, Uh, this mutation that we know reduces
Speaker 1: your odds of getting Alzheimer's? Could I do that as well?
Speaker 1: And then you know what if you add on other things?
Speaker 1: What if you add on things that are not don't
Speaker 1: have to do with immediately treating some ready to disorder,
Speaker 1: but you know, change a trait, change, hair color, change, height, change,
Speaker 1: all these things are are people are going to be
Speaker 1: comfortable with that? UM? And this all you know this
Speaker 1: science fiction writers have had a monopoly on this conversation
Speaker 1: until now, but I think that everybody else needs to
Speaker 1: be talking about it too. Now. As far as crisper
Speaker 1: altered genes go, given like a near future scenario, would
Speaker 1: they be detectable. What would somebody be able to say
Speaker 1: to to look at individual's genome and say, oh, well
Speaker 1: you've had there's gene altering evidence here. Or would a
Speaker 1: future civilization be able to look back at our genetic
Speaker 1: information and say, oh, well look here in this particular
Speaker 1: family line, we see evidence of of of of crisper alteration.
Speaker 1: That's an interesting question. Um, I think you would. I
Speaker 1: think that it would be possible if the people doing
Speaker 1: the crisper changing um left behind, you know, a mark
Speaker 1: of what they were doing, you know, a little water mark.
Speaker 1: Think of it that way. You know, some distinctive sequence
Speaker 1: of non coding DNA nearby that basically says hello, you know,
Speaker 1: this is this, this crisper alteration has brought to you
Speaker 1: courtesy of such and such hospital. You know, Um, you
Speaker 1: could totally code a message in DNA people. You know,
Speaker 1: people have enquoted entire books in DNA. Now, so you
Speaker 1: could do that. Um, But if you if somebody decided
Speaker 1: not to leave a water mark, then no, Actually, I
Speaker 1: think it might be very difficult to UM to say, oh, well,
Speaker 1: this person descends from a crispered ancestor knowing knowing tech
Speaker 1: companies I know we'd end up with like thirty page
Speaker 1: ELA agreements in there. Sure, absolutely, But you know the
Speaker 1: problem is that you know that over the generations they
Speaker 1: would get that agreement would mutate, and uh, you know,
Speaker 1: the legal language would would change into things that the
Speaker 1: lawyers didn't have in mind. So, given the great power
Speaker 1: that Crisper has to to allow us to alter our genes,
Speaker 1: what what do you think are the best ideas you've
Speaker 1: heard about how to guide it in a way that's
Speaker 1: that's fair, that's going to have good outcomes and not
Speaker 1: bad it. Uh, you know, the people have access to
Speaker 1: in in equitable ways. I mean, have you encountered anybody
Speaker 1: who has done the best what you would consider the
Speaker 1: best thinking so far on the ethics of gene alteration?
Speaker 1: You know, I I in the United States, the government
Speaker 1: is really just being very uh emphatic and not wanting
Speaker 1: to really talk about these issues at all. So uh,
Speaker 1: you know, not only is it not allowed to do
Speaker 1: germ line modification, but you can't do any research that
Speaker 1: might lead to that, and so um, we're not really
Speaker 1: having a meaningful conversation in the United States yet, I think, um,
Speaker 1: and uh, Unfortunately, what that means is that people are
Speaker 1: going to want to go to other countries where there
Speaker 1: is no particular regulation one or the other and do
Speaker 1: that in you know, in um, in you know clinic
Speaker 1: sort of on that are hidden from view. UM. And
Speaker 1: in my book I talk about one case where actually
Speaker 1: this has already happened. UM. A couple went to Mexico
Speaker 1: and an American doctor joined them there to uh to
Speaker 1: basically replace the mitochondria in this woman's eggs with with healthy,
Speaker 1: healthy ones. UM. So you know there are some genetically
Speaker 1: modified people alive today. UM. There there are a few, UM,
Speaker 1: but they're they're already here. UM. But they I think
Speaker 1: that it's a better, better way to deal with this
Speaker 1: is what England is doing. So in England this treatment
Speaker 1: called mitochondrial replacement therapy. UM. There was there was a
Speaker 1: lot of research that was done on it, UM and
Speaker 1: using animals, using using you know eggs, human eggs and
Speaker 1: so on and then UM and then Parliament actually had
Speaker 1: a big full debate about it and you know, the
Speaker 1: advantages and the possible risks and the ethics and so on,
Speaker 1: and then they decided, well we're going to allow this
Speaker 1: to happen, but it's going to happen under these rules.
Speaker 1: So you know, you can't just like walk into any
Speaker 1: doctor's office and get this therapy like that. You know,
Speaker 1: we're gonna really make really uh take We're gonna take
Speaker 1: real care to make sure that this has done safely
Speaker 1: and responsibly and under the right circumstances. And so now
Speaker 1: there is a university that has actually you know, gotten
Speaker 1: permission to basically open their doors for business. UM. And
Speaker 1: I think that's the way to go UM, because then
Speaker 1: you can you can have these discussions and say, like,
Speaker 1: you know what, as a society, we don't want uh
Speaker 1: people to be trying to make their kids more intelligent
Speaker 1: by altering their genes. We think that's a that's bad
Speaker 1: for individuals and bad for society. We're not going to
Speaker 1: allow it. UM, And that will actually happen rather than
Speaker 1: sending people to other countries to have you know, possibly
Speaker 1: dangerous treatments. UM. That's the way I think UH things
Speaker 1: should go. UM. And you can see an example of
Speaker 1: it in England, And it would be great if if
Speaker 1: the United States could follow suit. You know, on this
Speaker 1: show a lot we talked about how often like science
Speaker 1: fiction is sort of the playground for people working out
Speaker 1: these problems before they're dealt with in the real world.
Speaker 1: Have you encountered any any science fiction or fiction in
Speaker 1: general that you thought did a good job of dealing
Speaker 1: with you know, raised the interesting questions, had intelligent things
Speaker 1: to say about the implications of genetic engineering and humans.
Speaker 1: Oh yeah, I think that there's a long tradition of
Speaker 1: genetic engineering in science fiction. Um and uh and even
Speaker 1: before people really knew what genetic engineering was. You know,
Speaker 1: Brave New World is a fascinating book even now. I mean,
Speaker 1: and it's amazing think when you think how um, how
Speaker 1: much uh uh was just only discovered after the publication
Speaker 1: of the book. Um and I it's I find that
Speaker 1: one quite quite prophetic. I think the problem with science
Speaker 1: fiction comes when people think that anything can happen. That
Speaker 1: when people think that biology allows anything you can imagine
Speaker 1: to be a possibility. Um and the fact is that
Speaker 1: biology doesn't work that way. And so you know, when
Speaker 1: when we're actually talking, you know, today about well, what
Speaker 1: are the real possibilities that Crisper could create, I think
Speaker 1: we need to sort of I think we need to
Speaker 1: make sure that we're not um, just letting our fantasies
Speaker 1: run wild. You know, some people have said like, oh, well,
Speaker 1: you'll just be able to um Cristoper your kid and
Speaker 1: turn them into a genius. Um, and that it's not
Speaker 1: what science indicates. I mean, you know, intelligence is this
Speaker 1: incredibly complex phenomenon that is, you know, influenced by genes,
Speaker 1: it's influenced by the environment. It's partly a social thing,
Speaker 1: you know, in terms of like you know, intelligence really
Speaker 1: sort of gaining its meaning in you know, in a society. UM.
Speaker 1: And you can't just zoom in on a on a
Speaker 1: few genes and make a tweak here and there and
Speaker 1: say ah ha, like now my child is going to
Speaker 1: you know, get into the very best colleges. It just
Speaker 1: does not work that way. Um. And and I think
Speaker 1: that if people just go ahead with it anyway, UM,
Speaker 1: those children are going to be born, um, not just
Speaker 1: with these odd little changes to their genes, but with
Speaker 1: a whole huge set of expectations um from their parents.
Speaker 1: You know, I spent a hundred thousand dollar. There's a
Speaker 1: change your genes to make you a genius? And why
Speaker 1: are you getting these grades and math? What's what's wrong
Speaker 1: with you? I just see a That's where I see
Speaker 1: the real dystopia emerging is just expecting heredity to do
Speaker 1: much more than it can possibly do, uh to to
Speaker 1: alter ourselves. That's really interesting and it raises another question
Speaker 1: that definitely comes up in the book, which is that
Speaker 1: even when we're talking about traits that are to some
Speaker 1: large extent heritable, what are some of the reasons that
Speaker 1: it can create misunderstandings for us to talk about there
Speaker 1: being quote a gene for a certain trait. Yeah, we
Speaker 1: really have come to look at genes as being all
Speaker 1: powerful and and that is a real mistake and it's
Speaker 1: but it's hard to really, um get your head around
Speaker 1: the paradox of heredity in this regard um. And one
Speaker 1: of the examples I like to talk about is height.
Speaker 1: You know how it seems like it's simple, like it's
Speaker 1: just just a number that you get off a tape measure,
Speaker 1: Like how hard could that be to understand? But you know,
Speaker 1: in in fact, um, you know, heredity is this very
Speaker 1: weird mix of genes in the environment. Um, you know
Speaker 1: gene so height is is very what scientists say are
Speaker 1: very heritable, meaning that if you look at the variation
Speaker 1: among people in a particular population, why are they tall?
Speaker 1: Why they're short. Uh. You can explain a lot of
Speaker 1: that because of the genes that they inherited from their parents.
Speaker 1: So tall parents tend to have tall children. Short parents
Speaker 1: tend to have short children. And it's so that means
Speaker 1: it's very heritable. UM. But that does not mean that,
Speaker 1: you know, height is somehow um locked in and fixed that.
Speaker 1: It does not mean that you can actually, you know,
Speaker 1: finally predict um the you know, how tall it could
Speaker 1: will be just based on their gene. In fact, we
Speaker 1: didn't even know about any of these genes until the
Speaker 1: past decade or so. Uh. And now scientists are discovering
Speaker 1: literally thousands of genes that influence height, each one in
Speaker 1: a tiny little bit. You know, I got my genome
Speaker 1: sequence and discovered you know that I had very interested
Speaker 1: to find that at one particular gene was the first
Speaker 1: gene that was ever linked to height in population. And
Speaker 1: I'm I'm about an eighth of an inch taller than
Speaker 1: it would be otherwise because of the variant that I have.
Speaker 1: So you know, it's it's almost invisible. UM. But you know,
Speaker 1: the genetic influence just is the sum of all of
Speaker 1: these different variants. Um. And yet on top of all
Speaker 1: of that. UM. You know, you can have, you know,
Speaker 1: all the tall genes you want, but if you're not
Speaker 1: getting a good diet when you're a kid, and if
Speaker 1: you're facing dysentery on a regular basis, you're just not
Speaker 1: going to grow that tall because your body is going
Speaker 1: to be basically channeling all those resources to fighting disease
Speaker 1: and to you know, fight defend against starvation. And you know,
Speaker 1: on top of that, even more amazing to me is
Speaker 1: that in the whole world has actually gotten several inches
Speaker 1: taller over the past century because life overall is better.
Speaker 1: You know, there's more people have a better nutrition, better medicine.
Speaker 1: UM education probably plays a role in this. Uh. And
Speaker 1: so it's not that people inherited you know, quote unquote
Speaker 1: tall genes, it's that they inherited a world that favors
Speaker 1: greater height. So I've got one last question that might
Speaker 1: be kind of weird, but we'll see what you think
Speaker 1: of it. I often hear hear people talking about UM
Speaker 1: their relationship with their own genome, UM with their own
Speaker 1: genes in two basic ways. One is self identification. You know,
Speaker 1: it's like my genes are why I am like X.
Speaker 1: And so there there's a sort of I identify with
Speaker 1: my genes and lady. And then there's a kind of
Speaker 1: antagonistic kind of thing people think about with their genes,
Speaker 1: like the genes are this other disembodied force that made
Speaker 1: them and it's almost like another person that they have
Speaker 1: to negotiate with in some way. To what extent do you,
Speaker 1: given all of the research you've done and after having
Speaker 1: written this book, to what extent do you feel you
Speaker 1: are your genes or that your genes are this separate
Speaker 1: other force from you as a person. That's interesting. I yeah,
Speaker 1: I've heard that kind of language too, you know. And
Speaker 1: people will get their DNA sequenced and they'll discover they
Speaker 1: have a particular variant linked to some trade and say, ah,
Speaker 1: well that's why I do X Y Z or or
Speaker 1: they'll discover they have ancestry from a particular place and say, ah, well,
Speaker 1: that's why that's why I like to tell stories, or
Speaker 1: that's why I like to run, or what have you.
Speaker 1: Um And you know, you see ads on TV for
Speaker 1: these companies like ancestry dot Com that play on that
Speaker 1: exact attitude towards our genes that somehow, you know, what
Speaker 1: we do in our lives is encapsulated in these genes
Speaker 1: that we inherit from our ancestors. Um. And then yeah,
Speaker 1: then there are people who just want to fight against it, um,
Speaker 1: you know, and part of that sometimes feels like, you know,
Speaker 1: it's it's sort of a displaced fight they're having with
Speaker 1: their parents, you know, Like I'm not gonna be like
Speaker 1: you were, you know, and I don't care if I
Speaker 1: inherited genes from you. I'm going to be my own person, um,
Speaker 1: I would say, in my own experience. UM. You know,
Speaker 1: I got my genome sequence and part of the research
Speaker 1: for this book, and I really looked at it very deeply.
Speaker 1: It's been a fascinating experience. But I can't find anything
Speaker 1: in there that is quote unquote me. I think that
Speaker 1: it's just not there, you know. I I was able
Speaker 1: to look at the genes that I inherited from neandertals,
Speaker 1: you know, tens of thousands of years ago, and you know,
Speaker 1: which is fascinating. But then I say to these scientists, Okay,
Speaker 1: you've given me this catalog, got the indertal genes, let's
Speaker 1: talk about them, Like, what what does it mean that
Speaker 1: I inherit this particult? Like, here's one gene tell me
Speaker 1: about it and the sciences to be like, well, it
Speaker 1: looks like no one actually knows what this gene does
Speaker 1: at all, you know, and then that you're just sort
Speaker 1: of left there. But with the state of the science,
Speaker 1: you know, maybe I found that I have in the
Speaker 1: andertal gene that UM is linked to an increased risk
Speaker 1: of nose bleeds. I don't know. I don't know what
Speaker 1: to do with that, you know, And I it also
Speaker 1: makes me wonder why the inertals might have nosebleeds. But
Speaker 1: that's a whole separate issue. But you know, I I
Speaker 1: I don't I. I can't say that anything I've done
Speaker 1: looking at my own d d n A has given
Speaker 1: me some deep insight about my inner self as a person,
Speaker 1: you know, as it's much more relevant to me to
Speaker 1: think about, you know, how my parents raised me and
Speaker 1: what my experiences were as a kid, and what it
Speaker 1: has been lie you know, being married and and and
Speaker 1: being a father, like, the lived experience matters much more
Speaker 1: to me than UM than the details of the genome
Speaker 1: I inherited from my parents. UM. And that's that's kind
Speaker 1: of where where it stands for me now, all right, Yeah, well,
Speaker 1: well thank you so much, Carl. It's been a real
Speaker 1: pleasure talking to you today and we appreciate you taking
Speaker 1: time to speak with us. My pleasure, my pleasure. I
Speaker 1: really enjoyed the conversation and I'm glad you enjoyed the book.
Speaker 1: So there you have it. Thanks once again to Carl
Speaker 1: Zimmer for coming on the show and having this wonderful
Speaker 1: chat with us about his new book, She Has Her
Speaker 1: Mother's Laugh, The Powers, Perversions and Potential of Heredity Again.
Speaker 1: That's available in hardback, as a digital and as an
Speaker 1: audio book right now, and you can check out Carl's
Speaker 1: website Carl Zimmer dot com for even more about him
Speaker 1: and his projects. That's right, go to that website, and hey,
Speaker 1: be sure to check out our website as well. It's
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