Speaker 1: Hey, you welcome to Stuff to Blow your mind. My
Speaker 1: name is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Speaker 1: Time to go into the Old Vault. This time we're
Speaker 1: going in for an interview. I want to say that
Speaker 1: this was a really interesting interview. I really liked it.
Speaker 1: This is the interview we had with the science writer
Speaker 1: Carl Zimmer, originally published in June of about his book
Speaker 1: on heredity called She Has Her Mother's Laugh The Powers,
Speaker 1: Perversions and Potential of Heredity. And I thought this was
Speaker 1: a really good talk. Yeah, this was a lot of fun.
Speaker 1: You know, I just got him chatting about, you know,
Speaker 1: his experiences writing the book, uh, you know, some of
Speaker 1: the real you know, high points regarding like what heredity is,
Speaker 1: how it works, and and also I remember we got
Speaker 1: him talking a little bit about like okay, what if
Speaker 1: what if you were to write your name and someone's genes,
Speaker 1: Like how long would that signature last? Uh So, yeah,
Speaker 1: it's a fun conversation and uh, you know it was
Speaker 1: and it was on honor to get to talk to
Speaker 1: Carl Zimmer, who's, you know, such a big name in
Speaker 1: science communication. He's been one of my favorite science writers
Speaker 1: for years and it was really cool. All right, let's
Speaker 1: jump right in. Welcome to Stuff to Blow your Mind
Speaker 1: from how Stuff Works dot com. Hey you, welcome to
Speaker 1: Stuff to Blow your Mind. My name is Robert Lamb
Speaker 1: and I'm Joe McCormick. And boy, do we have a
Speaker 1: treat for you today. That's right, we're we're chatting with
Speaker 1: Carl Zimmer about his new book, She Has Her Mother's Laugh,
Speaker 1: The Powers, Perversions and Potential of Heredity. This is a
Speaker 1: fantastic book. I was trying to finish it before we
Speaker 1: talked to him today, and I was up till two
Speaker 1: am last night and getting to the very last page.
Speaker 1: But it was worth it. It is a great book.
Speaker 1: I really highly recommended. It's a brick that's just full
Speaker 1: of weird, interesting delights and insights about how our views
Speaker 1: of heredity have changed over the years, all of the
Speaker 1: good and all of the evil to that knowledge has
Speaker 1: been used for and uh and also where it's going
Speaker 1: in the future. Yeah, yeah, this it's a fascinating book.
Speaker 1: I also I got to see him in conversation with
Speaker 1: the Maria Knakova at World Science Festival this year, in
Speaker 1: which he talked about the themes in the book as well,
Speaker 1: So it was a real it's a real delight to
Speaker 1: have him here on the show. And if you want
Speaker 1: to check out She Has Her Mother's Laugh. It is
Speaker 1: available in hardback, digital and as an audio book. So, uh,
Speaker 1: we hope you enjoy our interview with him, but certainly
Speaker 1: go check out his book as well for just an
Speaker 1: in depth, riveting journey through heredity. Now, wait a minute,
Speaker 1: we should say who he is. I don't think we've
Speaker 1: done that if you're if you're not familiar with Carl
Speaker 1: Zimmer and Carl Carl Zimmer is a prolific, excellent science writer.
Speaker 1: He writes for the New York Times. I think I've
Speaker 1: also seen these articles in the Atlantic and National Geographic
Speaker 1: all over the place. Uh. He's written a lot about
Speaker 1: parasites and uh, some of the most interesting stuff in
Speaker 1: biology is is Karl's territory. And uh, and I really
Speaker 1: had a good time talking to him today. Yes, some
Speaker 1: of his past books include Parasite rex Evolution, The Triumph
Speaker 1: of an Idea, and Microcosm. So, without further ado, here's
Speaker 1: our conversation with Carl Zimmer. So, Carl, what led you
Speaker 1: to write a book about heredity. I guess in a way,
Speaker 1: I've been thinking about heredity for forever. Really. I mean,
Speaker 1: I when I was a kid, you know, I would
Speaker 1: uh think back on my ancestors that my parents told
Speaker 1: me about, and you know, I wonder like, oh wow,
Speaker 1: if if you know, Roger Goodspeed had not sailed from
Speaker 1: England to Massachusetts in the sixteen thirties, would I ever exist?
Speaker 1: You know, those sorts of things. And then when I
Speaker 1: became a father, I've got two teenage girls now, and
Speaker 1: you know that immediately brought to bear just how urgent
Speaker 1: and mysterious heredity can be. Because now they these two
Speaker 1: people walking around who have inherited a lot of my genes,
Speaker 1: and you know what, what is it that I'm giving
Speaker 1: them that that suddenly becomes a very pressing issue. And
Speaker 1: I guess what really then kind of crystallize it all
Speaker 1: for me, was that in the past few years, I've
Speaker 1: been doing a lot of reporting from the New York
Speaker 1: Times and elsewhere about the real revolution happening in biology,
Speaker 1: allowing scientists to sequenced DNA, to rewrite DNA, and to
Speaker 1: also look at other kinds of biology that might help
Speaker 1: uh create this thing that we call heredity. Uh, and
Speaker 1: so it just it all kind of came together, and
Speaker 1: I realized that this would be something that I really
Speaker 1: wanted to spend a couple of years really exploring deeply.
Speaker 1: So you mentioned the idea of the sort of personal
Speaker 1: curiosity about our ancestors, and you talk in the book
Speaker 1: about how we often do family genealogies to sort of
Speaker 1: learn something about ourselves, as if the seeds of who
Speaker 1: we are are somehow present in our really distant ancestors.
Speaker 1: But how many generations back do you have to go
Speaker 1: before those relationships with our ancestors really don't matter all
Speaker 1: that much in terms of genetic closeness. You know, you
Speaker 1: don't have to go back that far. And that just
Speaker 1: has to do with how parents passed down their DNA
Speaker 1: to their kids. You know, we each have two copies
Speaker 1: of each gene for the most part, but you know,
Speaker 1: parents only passed down one copy of a given gene
Speaker 1: to each child. And so if you repeat that process
Speaker 1: generation after generation, there's a sort of a kind of
Speaker 1: a stochastic, kind of random process that will basically lead
Speaker 1: to you know, uh, some descendants not having any DNA
Speaker 1: at all from a particular ancestor. Um, there's only so
Speaker 1: much room in your genome and you can't pack in
Speaker 1: all the DNA for all your ancestors basically, and so
Speaker 1: geneticis have done some back of the envelope calculations and
Speaker 1: if you go back let's say ten generations, um, that
Speaker 1: would be like your ancestors in the sixt dreds. Uh,
Speaker 1: maybe only about half of them have a genetic link
Speaker 1: to you. The rest they're still your ancestors. But you
Speaker 1: cannot point to any piece of DNA in your genome
Speaker 1: and say, oh, I got that from from this particular
Speaker 1: person you know. So Um, So I think that actually
Speaker 1: like really shows how we have to, um think think
Speaker 1: bigger when it comes to heredity. It's not just some
Speaker 1: particular bit of DNA that that gives heredity its meaning. Well,
Speaker 1: on the other side of that coin, UM, could you
Speaker 1: talk a little bit about what the Yale mathematician Joseph
Speaker 1: Chang discovered about human ancestry. It seems sort of like
Speaker 1: the flip side of what you're just talking about. Yeah,
Speaker 1: I mean, so you know, so much about heredity is
Speaker 1: counterintuitive and almost you know, it seems to contradict itself.
Speaker 1: And that's in a way what makes it so fascinating.
Speaker 1: So I just told you about how if you go
Speaker 1: back a certain number of generations, you're gonna encounter ancestors
Speaker 1: from whom you've inherited no DNA at all. Um. But
Speaker 1: there's an interesting feature of human ancestry, which is that, um,
Speaker 1: you know people uh, everybody today, Uh, you know, it
Speaker 1: shares a common ancestor with some people who lived about
Speaker 1: five thousand years ago, roughly speaking in other words, UM,
Speaker 1: if you, if you, it's just a you can and
Speaker 1: you can figure this out as just changed just by
Speaker 1: looking at Genealogy is a mathematical problem. Um, just think
Speaker 1: of think of our genealogy is a kind of a
Speaker 1: branching network. Um. The thing is though that uh you
Speaker 1: know are if you think about your family tree, um,
Speaker 1: and you think while as me, and then you branch
Speaker 1: off to your parents, and then they branch off to
Speaker 1: their parents and so on and so forth. Um. If
Speaker 1: you just keep branching in that simple way, you're gonna
Speaker 1: end up, you know, a few thousand years back with
Speaker 1: more ancestors than there are people who have ever lived.
Speaker 1: You know, we're talking chillions of people. And that's absurd.
Speaker 1: So so that's actually not a realistic model of your ancestry.
Speaker 1: The fact is that your aunt all of you know,
Speaker 1: your parents are cousins. Now either that you know, in
Speaker 1: some cases first cousins get married, but in other cases
Speaker 1: they're very distant cousins. Another what that means is that
Speaker 1: your parents share an ancestor, a common ancestor somewhere in
Speaker 1: the past. It could be hundreds of thousands of years ago,
Speaker 1: but it doesn't matter. They have an ancestor. So what
Speaker 1: that does is it folds the family tree back in
Speaker 1: on itself. And what Joseph Chang realized was that that
Speaker 1: actually does something very interesting to human ancestry. What it
Speaker 1: means is that you do not have to go back
Speaker 1: very far to find somebody who is the common ancestor
Speaker 1: of literally everyone on earth. Uh And it's just in
Speaker 1: the past few thousand years that you could find people
Speaker 1: like that. Um. Now, of course you know those common ancestors,
Speaker 1: you know they for each of us that that that's
Speaker 1: one person or a few people out of thousands upon
Speaker 1: thousands of ancestors. But it's something that ties us all together.
Speaker 1: And the irony is that you know, people are really
Speaker 1: uh uh, really love to connect themselves to someone famous.
Speaker 1: You know, like, oh, did you know that I am
Speaker 1: descended from William the Conqueror? And the fact is that
Speaker 1: probably probably everybody of European descent is and is a
Speaker 1: descendant of William the Conqueror. Probably everybody of European descent
Speaker 1: is a descendant of Charlemagne Um. And you know, it's
Speaker 1: possible that everybody on earth is a descendant of you know,
Speaker 1: maybe Cleopatra. It's like, that's just the nature of human
Speaker 1: genealogy is that it's we're all descended from kings. That
Speaker 1: doesn't make anybody special. Well as as long as we're
Speaker 1: gazing backwards in time, here, can you tell us how
Speaker 1: ancient thinkers contemplated heredity? The weird thing is that they
Speaker 1: really didn't. And they at least they didn't think about
Speaker 1: heredity in the way that we do. Uh. You know,
Speaker 1: if you go back and you you look at what
Speaker 1: Hippocrates would say or Aristottle would say, Uh, this, this
Speaker 1: whole model of how we inherit something you know, microscopic
Speaker 1: and biological that that determines how we ended up the
Speaker 1: way we are just would not compute for them. And so,
Speaker 1: you know, you know, someone like Aristotle would say like, well,
Speaker 1: you know, the thing that one generation looks like the
Speaker 1: previous one is just because it's the same chemistry. Um,
Speaker 1: you know, of course you're going to be the uh,
Speaker 1: you're going to be the same because you know, it's
Speaker 1: the same set of processes that produced a person that
Speaker 1: produced you. So what's the big deal? And you know
Speaker 1: the word heredity, You know, it's a very old word,
Speaker 1: but it only referred to basically inheriting stuff. Um, you know,
Speaker 1: and I'm talking not talking about jeanes, 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 Mathenniel now is starting to get older and
Speaker 1: he's developing kidney stones, and it occurs to him that
Speaker 1: his father had kidney stones and around the same age,
Speaker 1: and he basically writes success saying, well, what is up
Speaker 1: with that? Now? Did I get these kid stones from
Speaker 1: 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 jeans, 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 select the breeding
Speaker 1: of animals and plants inform classical and medieval thinkers at
Speaker 1: all about the possible nature of heredity, because it seems
Speaker 1: it's I mean, it's kind of seems like people such
Speaker 1: as Aristotle or Albertus Magnus would have would have looked
Speaker 1: at how we bred flowers, crops and farm animals more
Speaker 1: were at least in addition to the influence of geography
Speaker 1: or experience, you would think so, I would I would
Speaker 1: have thought so. But I think that's because we are
Speaker 1: in the century and we look back and say, well,
Speaker 1: everyone must have thought the way we did. But there
Speaker 1: are actually, you know, whole books written, uh you know
Speaker 1: by Roman writers about farming for example, UM, and you
Speaker 1: can search them as I mean, I have sat down
Speaker 1: and look through these books for anything resembling what you're
Speaker 1: talking about, and it's just not there. They do not
Speaker 1: talk about, oh, well, there's some you know quality in
Speaker 1: this particular variety of olives that you know, if you
Speaker 1: if you, if you breed it, it will pass it
Speaker 1: down to two future generations of olive trees. That this
Speaker 1: isn't there. Instead, they'll say like, well, make sure that
Speaker 1: you know you're you're growing it on good soil, make
Speaker 1: sure your your farm gets a good supply rain. It's
Speaker 1: all about the environment. And it isn't really until I
Speaker 1: would argue, it's not really until the seventeen hundreds that uh,
Speaker 1: you start to see these farmers, these livestock breeders really
Speaker 1: take interest in this um. And part of it is
Speaker 1: that these European countries are all um looking for ways
Speaker 1: to use science to uh make their countries wealthier. And
Speaker 1: you know they're thinking, well, if we can we can,
Speaker 1: if we can produce new varieties of animals implants, um,
Speaker 1: then we we will enrich ourselves. Uh. And there's this
Speaker 1: one breeder named Robert Bakewell who produces an entirely new
Speaker 1: eat of sheep just by starting to think about heredity,
Speaker 1: to think about which individuals those sheep is he gonna
Speaker 1: mate together? Is he gonna just only mate within his flock?
Speaker 1: Is he gonna go pick out other ones from other
Speaker 1: flocks to mate? Um? And lo and behold he produces
Speaker 1: this this very successful new breed. And you know, people
Speaker 1: like Charles Darwin look at that and say, what has happened?
Speaker 1: How did they do that? Um? And in Germany and
Speaker 1: in Central Europe there's a big push to do the
Speaker 1: same thing with sheep, to do that with crops as well,
Speaker 1: and uh and to try to understand what are these rules.
Speaker 1: And one of those people who's trying to understand those
Speaker 1: rules is none other than Gregor mendel Um. So his
Speaker 1: his breeding experiments. You know, the foundation of genetics comes
Speaker 1: out of this new push to try to use heredity
Speaker 1: to enrich nations. All Right, we're gonna take a quick
Speaker 1: break and then we're gonna jump right back in to
Speaker 1: the interview and we're back. So at what point does
Speaker 1: the modern idea of heredity really emerge. Well, I'd say
Speaker 1: in the late eighteen hundreds, UM, people start to talk
Speaker 1: about heredity as a scientific question. And Charles Darwin is
Speaker 1: really important in all of this because, you know, he
Speaker 1: comes up with this theory of evolution and it depends
Speaker 1: on heredity. In other words, Um, you know, the only
Speaker 1: way for natural selection to work is so if parents
Speaker 1: can pass down traits to their offspring to give them
Speaker 1: some advantage and surviving and reproducing. And so it's very
Speaker 1: obvious to Darwin that, you know that that heredity is
Speaker 1: this huge glaring question in the middle of his theory,
Speaker 1: and he and he works really hard to try to
Speaker 1: find out for himself how heredity works. And he's very
Speaker 1: aware of a lot of the research that's going on
Speaker 1: at the time looking to the discovery of cells and
Speaker 1: the discovery that there are a little things inside of cells,
Speaker 1: but no one's quite sure what they are, UM. And
Speaker 1: so he developed a theory that there are particles in
Speaker 1: the cells throughout our body that they somehow stream into
Speaker 1: the eggs and sperm and uh then become something like
Speaker 1: we the way we think of genes um. That doesn't
Speaker 1: pan out. You know, his cousin Francis Galton, tries to
Speaker 1: test it by injecting blood from uh, you know, black
Speaker 1: rabbits into white rabbits, you know, different colored rabbits, and
Speaker 1: seeing if that changes the color of their offspring. Doesn't happen.
Speaker 1: Uh and uh So it's not really until after Darwin
Speaker 1: is dead that scientists start to really understand chromosomes and
Speaker 1: then rediscover mental and it all clicks together, and the
Speaker 1: science that they that they call genetics is born in
Speaker 1: nineteen uh and and you know, the it's really you
Speaker 1: can see how exciting it is for the scientists at
Speaker 1: the time. William Bateson, who coined the term genetics, he
Speaker 1: writes at the time that you know, the science of
Speaker 1: heredity has been revolutionized. You know that finally they feel
Speaker 1: like they can they can understand heredity um in its
Speaker 1: fundamental basis. So so how do we go from this
Speaker 1: point of of of just excitement and discovery and just
Speaker 1: fall so steeply into eugenics and then ultimately the horrors
Speaker 1: of the Third Reich. Well, if you look back, the
Speaker 1: roots of eugenics UM go back pretty far. Um. You
Speaker 1: know so Uh. On the one hand, Uh, so our
Speaker 1: modern conception of race UH starts to develop as early
Speaker 1: as really the fifteen hundreds are the fourteen hundreds, even
Speaker 1: where in Spain, uh, Jews are are being considered a
Speaker 1: separate race of people, and and and noble families have
Speaker 1: to do have to draw out genealogies to prove that
Speaker 1: they don't have any Jews in their in their ancestry. Um.
Speaker 1: Otherwise they you know, they won't be able to get
Speaker 1: that good job in government or so on. And so
Speaker 1: that starts to develop this idea that that groups of
Speaker 1: people are fundamentally different in some way that is carried
Speaker 1: 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? Okay?
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 as these
Speaker 1: people who have who we believe have genes that we
Speaker 1: don't like, and we want to prevent them from reproducing,
Speaker 1: because that's going to drag down our country, and so
Speaker 1: what are we going to do to keep them from reproducing?
Speaker 1: And um, that leads to sterilization and much worse. So,
Speaker 1: in reading your chapter about Henry Goddard and the origins
Speaker 1: of the American eugenics movement, I'm struck that this is
Speaker 1: a potential example of the dangers of bad research. Like
Speaker 1: you draw a really disturbing picture of how but like
Speaker 1: sloppy or fraudulent work that became the basis of Henry
Speaker 1: Goddard's published writings on heredity can be viewed in some
Speaker 1: ways is contributing directly to real world consequences, like the
Speaker 1: horrors of for sterilization in the United States or mass
Speaker 1: murder in Europe. Do you ever think, when you see
Speaker 1: bad science or pseudoscience being being publicized today that it
Speaker 1: could ever lead to such nightmares that even its authors
Speaker 1: might not have imagined? Uh, you know, I don't. I
Speaker 1: think that we can't uh rule out those kinds of possibilities.
Speaker 1: I mean, it might be very, very unlikely, but I mean,
Speaker 1: if you look at history, you can see how bad
Speaker 1: science combined with existing prejudices led to really horrific outcomes.
Speaker 1: And it wasn't that the science was somehow appropriated by
Speaker 1: pseudo scientists or something. Uh. Eugenics was embraced by most
Speaker 1: of the leading um biologists of the time. Uh and Uh,
Speaker 1: there were different forms of eugenics, you know. So some
Speaker 1: people were very much sort of concerned. We were quite
Speaker 1: racist and you know, concerned about uh, you know, the
Speaker 1: white quote unquote race being you know, polluted by other races. Um.
Speaker 1: But then there were progressives who thought that this was
Speaker 1: going to be part of their grand plan for making
Speaker 1: society a better, fairer place. Um. And I think it's
Speaker 1: really important to look at these episodes in history to
Speaker 1: see how things go bad. Um. And I think it's
Speaker 1: I think it's arrogant for any of us to say, well,
Speaker 1: things like this could never happen again, you know, and
Speaker 1: somehow we're vaccinated from from these sorts of things. But
Speaker 1: we can draw lessons from the past, and we can
Speaker 1: see how, um, how humble we need to be in
Speaker 1: the face of complexity in in our own biology. You know.
Speaker 1: We you know, I think we're in like in another revolution,
Speaker 1: the way we were a hundred years ago, you know,
Speaker 1: a hundred years ago, genetics itself was profoundly new. That
Speaker 1: gene was a new thing. Uh. Now we're at the
Speaker 1: point where we're looking at genomes, in other words, all
Speaker 1: the genes in our in our selves, and we can
Speaker 1: we can see them down to the atomic detail. UM,
Speaker 1: but there's still a vast amount we do not understand
Speaker 1: about it, and UM, you know, we we cannot let
Speaker 1: that be an opportunity to uh, you know, card out
Speaker 1: our old biases and prejudices and say, oh, I see
Speaker 1: now science backs up what I was saying all along
Speaker 1: about those other people. UM, we can't. We just we
Speaker 1: cannot let that happen again. I think that's a really
Speaker 1: good point. And I also think you can even look
Speaker 1: at it as there's a flip side to it where
Speaker 1: modern discoveries of genomics really complicate or in some sense
Speaker 1: is undermine what many people have traditionally understood as the
Speaker 1: concept of race within humans. Right. Yeah, So the scientific
Speaker 1: concept of race UH developed in in the seventeen hundreds,
Speaker 1: and it was really UM very much spurred on by
Speaker 1: UH by what Europe was doing at the time. So
Speaker 1: Europe was in the midst of building up huge colonies
Speaker 1: UM and enslaving many many people. There was a need
Speaker 1: for sort of legal and moral justifications for doing this,
Speaker 1: and a lot of it, uh was based on these
Speaker 1: concepts of race, so that for example, you know, Africans
Speaker 1: were were claimed to be a completely separate race, uh
Speaker 1: that you know, had inherent uh inferiority to the white race.
Speaker 1: And so therefore slavery is okay. And you can see
Speaker 1: this again and again in in lots of lots of
Speaker 1: writing at the time. Uh. Now, even in the early
Speaker 1: nineteen hundreds, Um, there were there were indications that this
Speaker 1: kind that genetics was not aligning with these these uh
Speaker 1: old ideas about race. They just weren't fitting neatly. Um.
Speaker 1: You it was very it was it was becoming harder
Speaker 1: and harder to sort of draw any particularly bright line
Speaker 1: 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 we're 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 whole genomes. Um. Yeah, the whole
Speaker 1: thing with race now is is it just is it's
Speaker 1: a bit one. The way one Jenet has put it
Speaker 1: to me is, well, you know, like talking for us,
Speaker 1: like talking about races, like the way Greeks talked about
Speaker 1: 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 genets are 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 if 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 sighting possibility is what you referred to as
Speaker 1: epigenetics and epigenetics is kind of a broad term, but
Speaker 1: roughly speaking, what it refers to is the molecules inside
Speaker 1: our cells that control our genes. That that allows some
Speaker 1: genes to be switched on and to produce proteins and
Speaker 1: others that are kept silent um. And you know, it's
Speaker 1: it's very clear that this is incredibly important to our existence.
Speaker 1: You know, it's what makes your skin cells be skin cells,
Speaker 1: and you're you know, brain cells be brain cells, like
Speaker 1: they are using different genes in the same genome. And
Speaker 1: when these cells divide um, the you know, a skin
Speaker 1: cell does not normally instantly become a neuron or or
Speaker 1: you know it doesn't you don't grow a tooth on
Speaker 1: your back of your hand um. And that has to
Speaker 1: do with epigenetics um. And so what does this have
Speaker 1: to do with heredity, Well, you know, when the cells divide,
Speaker 1: there are basically inheriting the genes and the epigenetics of
Speaker 1: their mother's cell. But you know that the possibility rises, well,
Speaker 1: what if you pass those down to the next generation altogether,
Speaker 1: you know, through eggs and sperm um. And there's some
Speaker 1: evidence that that that can happen. And what makes us
Speaker 1: especially exciting is that you know, through our lives, experiences
Speaker 1: can change the epigenetic makeup of ourselves. You know, so
Speaker 1: if you if you get sick, if you smoke, if
Speaker 1: you experience stress, those all seemed 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.
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 it, and that that really
Speaker 1: is something that happens. You know, a plant goes through
Speaker 1: a drought and generations later there's still an epigenetic mark
Speaker 1: on its descendants. So yeah, epigenetics is in a really
Speaker 1: exciting area. So you just alluded to some of the
Speaker 1: controversy about epigenetics, and I guess there are other forms
Speaker 1: of ideas of non genetic inheritance, but epigenetics in some
Speaker 1: ways still remains controversial, especially in humans. Like you're talking about,
Speaker 1: if you're comfortable speculating and if you had to guess,
Speaker 1: how would you imagine our picture of non genetic inheritance
Speaker 1: might change over the next fifty years or so? What's
Speaker 1: your sense? You know? I think that it is actually
Speaker 1: possible that we'll just find that, um, human epigenetics is
Speaker 1: just not really that important. I mean, I'm actually I
Speaker 1: think there's a reason to be kind of pessimistic. Um
Speaker 1: that you know, there are these very cantalizing studies, but
Speaker 1: they're small, and they could just be the result of
Speaker 1: noise and so on, and and yet you know, we
Speaker 1: really want epigenetics to be real. Um. I mean, epigenetics
Speaker 1: has totally taken hold of the popular consciousness. And you know,
Speaker 1: I was astonished to learn not long ago that you
Speaker 1: can take classes and epigenetic yoga, which is not kidding,
Speaker 1: you can google it. And the thinking is, the claim
Speaker 1: is that you know that by doing this yoga you
Speaker 1: change the epigenetic profile of yourselves. And you know 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: the 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
Speaker 1: culture UM is actually, I I would argue, an incredibly
Speaker 1: important form of forredity, especially for our species. We we
Speaker 1: passed down not just our genes to the next generation,
Speaker 1: but all of our knowledge and and beliefs and customs
Speaker 1: and so on, and those those get propelled down through
Speaker 1: the generations UM in a very hereditary way and UM,
Speaker 1: and that's actually very different from other species. And I
Speaker 1: would and you know in the book, I talk about
Speaker 1: how you could argue that civilization itself is the product
Speaker 1: of our very special form of cultural inheritance. So in
Speaker 1: talking about non genetic inheritance, you've got potentially epigenetics, though
Speaker 1: the juries out on that, you've got, you've got culture.
Speaker 1: But we should talk a little bit about microbiology. Can
Speaker 1: you tell the story of how you found out that
Speaker 1: your belly button contained bacteria only known to exist in
Speaker 1: the Mariana Trench? Absolutely? Yeah. So I've been incredibly fascinated
Speaker 1: by the microbiome, you know, all the bacteria that live
Speaker 1: on us and in us. For quite some time, him
Speaker 1: In and I have been doing some reporting on it
Speaker 1: as scientists have found new ways to to explore our microbiome.
Speaker 1: And it used to be that you just have to
Speaker 1: scrape you know some you know, a little bit of
Speaker 1: skin or take a stool sample and taken into a
Speaker 1: lab and try to grow bacteria. And the fact is
Speaker 1: that very few of the bacteria that live on us
Speaker 1: uh or in us enjoy being in a petri dish
Speaker 1: on their own. It just it makes them miserable and
Speaker 1: they don't grow. So we had a very impoverished view
Speaker 1: of 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 there 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 their 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 dunt get in a little tube.
Speaker 1: But they gave me and handed it back. And then
Speaker 1: they went off and they looked at all the DNA
Speaker 1: there was on that cute tip, and you know, a
Speaker 1: lot of it was my own skin cells, but then
Speaker 1: a whole lot of it was not um. And actually
Speaker 1: they identified fifty three species as I recall, of bacteria
Speaker 1: just in my belly button, and uh, it was amazing
Speaker 1: to to look at, uh the information about each of
Speaker 1: those species. And so one of them it had only
Speaker 1: it's only known from a sample at the bottom of
Speaker 1: the ocean. They marry on a trench um. And there's
Speaker 1: another one that I have that's only been found in
Speaker 1: soil in Japan. I've never been to Japan, so um.
Speaker 1: But you know, this was entirely unsurprising to this scientist,
Speaker 1: because you know, he was looking at lots of people
Speaker 1: and was finding people with you know, over a hundred
Speaker 1: species just in their belly button alone and from all
Speaker 1: sorts of different places. UM. So what does this have
Speaker 1: to do with heredity? Well, you know, I I did
Speaker 1: not inherit that marry on a trench bacteria from my parents. UM.
Speaker 1: It's just you know, we have all of this, these
Speaker 1: these bacteria in the environment, um, and some of them
Speaker 1: have become very well adapted to living on our body um,
Speaker 1: and we just pick them up um through our life.
Speaker 1: But it does seem that the microbiome that there is
Speaker 1: some heredity to it. UM. The best examples come from
Speaker 1: certain animals like that passed down bacteria to their offspring.
Speaker 1: Then these bacteria can only live inside these animals, and
Speaker 1: without those bacteria, these animals die. The cockroaches are actually
Speaker 1: a great example of this. So you know, one reason
Speaker 1: the cockroaches are so successful is because they harbor one
Speaker 1: species of bacteria in a special little organ um where
Speaker 1: it breaks down some of their food and gives them nutrients. Um.
Speaker 1: And these bacteria never live outside of the cockroaches, and
Speaker 1: actually they're they're sitting inside of cockroach cells and then
Speaker 1: in the female cockroaches, those cells crawl over to an
Speaker 1: egg and rip open, and then the bacteria infect the eggs,
Speaker 1: so that cockroaches are born completely infected with these bacteria.
Speaker 1: That's that to me, just seems that's heredity. I mean,
Speaker 1: these bacteria are being passed down from millions of years
Speaker 1: from parents to offspring. Um. So the question now is, well,
Speaker 1: are is that true for humans? Um? Maybe not, uh,
Speaker 1: you know, in that particular way, but um, you know,
Speaker 1: it is possible that there are a lot of species
Speaker 1: that are very much adapted to us. You know, maybe
Speaker 1: mothers are passing down certain kinds of bacteria and the
Speaker 1: birth canal or during breastfeeding. Um. And maybe the most
Speaker 1: dramatic example of all is that in all of ourselves
Speaker 1: we generate fuel with these little blobs called mitochondria, which
Speaker 1: have their own DNA in them. And the reason they
Speaker 1: have their own DNA is because they started out as
Speaker 1: bacteria and about two billion years ago and our single
Speaker 1: celled ancestors, those bacteria infected our ancestors and then took
Speaker 1: up permanent residence in there and we cannot live without
Speaker 1: them today. So um so, so MicroB is gonna have
Speaker 1: a very powerful part in heredity. Do you think our
Speaker 1: expanding consciousness about the full scope of heredity, from like
Speaker 1: cross generation into symbionts or even to camerism, should force
Speaker 1: us to re examine our ideas about what it means
Speaker 1: to be an individual and individual animal and what the
Speaker 1: biological and categorical boundaries of the self really are. Absolutely, uh,
Speaker 1: you know, I think that uh, you know, heredity does
Speaker 1: not actually follow a lot of the simple rules that
Speaker 1: we assume it does, uh, and it and it does
Speaker 1: bring into question what it means to be an individual
Speaker 1: because you know, we think of he started out with
Speaker 1: some original genome in a fertilized egg, so we inherited
Speaker 1: half of that genome for me to our parents. It
Speaker 1: came together in this new combination and that's us. But
Speaker 1: you know that is not actually us. Um and in
Speaker 1: lots of different ways. So in one way, I mean,
Speaker 1: if you actually follow the cells that divide in an embryo,
Speaker 1: those cells can mutate and then you tate again and
Speaker 1: youtate again, so that if you were to look at, say,
Speaker 1: any two neurons in your brain, they would be different
Speaker 1: from each other because they have acquired different mutations as
Speaker 1: we developed. UM. So there is no one genome in
Speaker 1: our body because we are what scientists say call us
Speaker 1: our mosaics. UM. But then that's not the not the
Speaker 1: end of it. Um. So you know, we think of
Speaker 1: heredity is going down through the generations, but heredity can
Speaker 1: also come back up in reverse. Uh. And so one
Speaker 1: example of this is um when when and become pregnant, uh,
Speaker 1: cells from their fetus will circulate around in their blood.
Speaker 1: You can actually you can actually draw blood from a
Speaker 1: pregnant woman and sequence the genome of the fetus. Uh.
Speaker 1: We that is done in a regular basis. Now uh
Speaker 1: after pregnancy, Uh, those fetal cells may go away because
Speaker 1: of the mother's immune system is clearing them out. But
Speaker 1: surprisingly often UH those cells can establish them cells in
Speaker 1: a mother's liver or thyroid gland, even her brain. And
Speaker 1: scientists refer to uh such people as chimeras. Um. It's
Speaker 1: after the you know, the beast of Greek mythology. And
Speaker 1: you can get chimeras also from twins in the womb
Speaker 1: who are sharing DNA sharing cells uh. And so you
Speaker 1: can literally like have um. You know that one of
Speaker 1: the first discoveries of this was a woman who gave
Speaker 1: blood in the nineteen fifties and totally baffled the blood
Speaker 1: bank because she was giving two types of blood at
Speaker 1: the same time. And he said, this is not possible.
Speaker 1: You know, there must be some contamination somewhere. But it
Speaker 1: turned out that her blood was made up from two individuals,
Speaker 1: herself and a twin who had died when he was
Speaker 1: in infancy. Uh. And so you know, and this is
Speaker 1: not something that's rare. Timerism is probably quite common among humans,
Speaker 1: and it really challenges these these ideas that we we
Speaker 1: tell ourselves about heredity and individuality. One of the weirdest
Speaker 1: and most interesting types of heredity you discussed in the
Speaker 1: book is that I think you said it's eight or
Speaker 1: so lines of contagious cancer found in nature so far.
Speaker 1: Can you talk a little bit about contagious cancer and
Speaker 1: does it make sense to think of this cancer as
Speaker 1: an independent animal or organism of its own type, or
Speaker 1: as sort of an infection from an original animals genome. Yeah,
Speaker 1: this is where credity gets really weird, because you know,
Speaker 1: when when cancer arises in our bodies, it's a it's
Speaker 1: another 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 allow them to
Speaker 1: reproduce quickly and to be very aggressive and destructive. Now,
Speaker 1: UM cancer usually UH, you know, either is wiped out
Speaker 1: by the body or is lethal. In either case, you
Speaker 1: don't have cancer surviving beyond the life of its host.
Speaker 1: We we think of that as being weird, but it
Speaker 1: turns out that in fact cancer can endure UM. And
Speaker 1: this was really first discovered UM in in a uh
Speaker 1: in a case with dogs where dogs would be uh
Speaker 1: developing UM these these tumors UH, and it was very
Speaker 1: odd that they the cancer seemed to spread like an
Speaker 1: infectious disease, and so people scratching their head over this,
Speaker 1: and then they realized that actually what had happened was
Speaker 1: that the cancer cells themselves were spreading from one dog
Speaker 1: to another to another UM and so that the cancer
Speaker 1: cells were not in fact related to the dogs that
Speaker 1: they were in. And if you look at the DNA
Speaker 1: of this cancer, it goes back to some dog that
Speaker 1: lived maybe ten thousand years ago, and it has just
Speaker 1: been spreading from dog to dog ever since, and it's
Speaker 1: been mutating along the way. And it's and so it's
Speaker 1: the thing that you know, it's it's what you call it.
Speaker 1: I mean I don't know what we could call it,
Speaker 1: but you know, some have argued that it should be
Speaker 1: just given its own species name, because it's it's this,
Speaker 1: it's this lineage of animal cells that has its own
Speaker 1: genome UM, and has its own way of getting around
Speaker 1: in the world. It's it's doing just flying UM. So
Speaker 1: surely it deserves a name. UM. And then it turns
Speaker 1: out that in a few other cases, scientists have founded
Speaker 1: another species, so Tasmanian devils in Tasmania, they get a
Speaker 1: facial tumor because they bite each other when they're fighting,
Speaker 1: and they spread this cancer to each other. UM. And
Speaker 1: this this cancer has actually arisen a couple of times
Speaker 1: in Tasmania just in recent decades, so it isn't something
Speaker 1: that only happened once a long time ago. And what's
Speaker 1: most mind blowing is that some scientists stumbles across this
Speaker 1: yet again, just in the past few years, UH in clams,
Speaker 1: in shellfish UH and have discovered that there there's contagious
Speaker 1: cancer in the ocean. UM. So you're swimming. As you're
Speaker 1: swimming in the ocean, you're swimming around cancer cells that
Speaker 1: are moving from host to host. An infectious cancer as
Speaker 1: its own type of organism. What kingdom of life would
Speaker 1: that be? Would it be an animal? I yes, it
Speaker 1: 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, canus canus
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 cells. 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 years ago,
Speaker 1: that that would be weird. Yeah. Alright, time for a
Speaker 1: quick break. Then we will be right back for more
Speaker 1: of our conversation with Carl zimmer Than. All right, we're
Speaker 1: back now. We can't talk about the future of heredity
Speaker 1: without touching on crisper. How is this technology affecting the
Speaker 1: future of human redity? Well, you know, we're going to
Speaker 1: have to wait and see exactly what happens, but certainly
Speaker 1: the potential is profound. UM Crisper is just a few
Speaker 1: years old, and it's this is this technology essentially to
Speaker 1: zero in on any particular bit of DNA, cut it out,
Speaker 1: and if you want, insert a different little stretch of
Speaker 1: DNA in there. So um, this raises the possibility of
Speaker 1: being able to cure hereditary diseases by rewriting uh, the
Speaker 1: DNA in cells, you know, to repair or 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: hunting news disease. But what if somebody says, well, yeah,
Speaker 1: but I want I'm using IVF and I want to
Speaker 1: just give my kids, Uh, this mutation that we know
Speaker 1: reduces your odds of getting Alzheimer's? Could I do that
Speaker 1: as well? And then you know what if you add
Speaker 1: on other things? What if you add on things that
Speaker 1: are not don't have to do with immediately treating some
Speaker 1: pready disorder, but you know, change a trait, change, hair color, change, height, change,
Speaker 1: all these things are people who 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 I think you would.
Speaker 1: I think that it would be possible if the people
Speaker 1: doing the crisper changing um left behind, you know, a
Speaker 1: mark of what they were doing, you know, a little
Speaker 1: water mark. Think of it that way. You know, some
Speaker 1: distinctive sequence of non coding DNA nearby that basically says hello,
Speaker 1: you know this is this, this crisper alteration has brought
Speaker 1: to you courtesy of such and such hospital. You know, UM,
Speaker 1: you could totally encode a message in DNA people. You know,
Speaker 1: people have enquoded 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 companies.
Speaker 1: I know we'd end up with like thirty page el
Speaker 1: agreements in there, sure absolutely, But you know the problem
Speaker 1: is that you know that over the generations that would
Speaker 1: get that agreement would mutate and uh, you know, the
Speaker 1: legal language would would change into things that the lawyers
Speaker 1: didn't have in mind. So given the great power that
Speaker 1: crisper has to to allow us to alter our chenes,
Speaker 1: what what do you think are the best is you've
Speaker 1: heard about how to guide it in a way that's
Speaker 1: that's fair, that's uh going to have good outcomes and
Speaker 1: not bad that uh you know the people have access
Speaker 1: to in in equitable ways. I mean, have you encountered
Speaker 1: anybody who has done the best what you would consider
Speaker 1: the 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
Speaker 1: think UM and UH. Unfortunately, what that means is that
Speaker 1: people are going to want to go to other countries
Speaker 1: where there is no particular regulation one or the other
Speaker 1: and do that in you know, in UM, in you know,
Speaker 1: clinics or that are hidden from view. UM. And in
Speaker 1: my book I talk about one case where actually this
Speaker 1: has already happened. UM. A couple went to Mexico and
Speaker 1: an American doctor joined them there to uh to basically
Speaker 1: 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 uh
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 talk 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: A Brave New World is a fascinating book even now.
Speaker 1: I mean, and it's amazing when you think how um,
Speaker 1: how much uh uh was just only discovered after the
Speaker 1: publication of the book. Um and I 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,
Speaker 1: well you'll just be able to um Christoper your kid
Speaker 1: and and turn them into a genius. UM. And that
Speaker 1: it's not what science indicates. I mean, you know, intelligence
Speaker 1: is this incredibly complex phenomenon that is, you know, influenced
Speaker 1: by genes, it's influenced by the environment. It's partly a
Speaker 1: social thing, you know, in terms of like you know,
Speaker 1: intelligence really sort of gaining its meaning in you know,
Speaker 1: in a society. UM. And you can't just zoom in
Speaker 1: on a on a few genes and make a tweak
Speaker 1: here and there and say ah ha, like now my
Speaker 1: child is going to you know, get into the very
Speaker 1: best colleges. It just does not work that way. UM.
Speaker 1: And and I think that if people just go ahead
Speaker 1: with it anyway, UM, those children are going to be born, um,
Speaker 1: not just with these odd little changes to their genes,
Speaker 1: but with a whole huge set of expectations um from
Speaker 1: their parents. You know, I spent a hundred thousand dollars
Speaker 1: to change your genes to make you a genius. And
Speaker 1: why are you getting these grades in math? What's what's
Speaker 1: wrong with you? I just see a That's where I
Speaker 1: see the real dystopia emerging. Is just expecting heredity to
Speaker 1: do much more than it can possibly do, uh to
Speaker 1: to alter ourselves. That's really interesting and it raises another
Speaker 1: question that definitely comes up in the book, which is
Speaker 1: that even when we're talking about traits that are to
Speaker 1: some large extent heritable, what are some of the reasons
Speaker 1: that it can create misunderstandings for us to talk about
Speaker 1: there being quote a gene for a certain trait. Yeah,
Speaker 1: we really have come to look at genes as being
Speaker 1: all powerful and and that is a real mistake and
Speaker 1: it's but it's hard to really um get your head
Speaker 1: around the paradox of heredity in this regard um. And
Speaker 1: one of the examples I like to talk about is height.
Speaker 1: You know, height seems like it's simple, like it's just
Speaker 1: it's 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 scientist say, very heritable,
Speaker 1: meaning that if you look at the variation among people
Speaker 1: in a particular population. Why are they tall, why are
Speaker 1: they're short? Uh, you can explain a lot of that
Speaker 1: 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 law sped in and
Speaker 1: fixed that. It does not mean that you can actually,
Speaker 1: you know, finally predict um the you know how tall
Speaker 1: it could will be, just based on their genes. In fact,
Speaker 1: we didn't even know about any of these genes until
Speaker 1: the past decade or so. Uh. And now scientists are
Speaker 1: discovering literally thousands of genes that influence height, each one
Speaker 1: in a tiny little bit. You know, I got my
Speaker 1: genome sequence and discovered you know that I had. It's
Speaker 1: very interested to find that a one particular gene. It
Speaker 1: was the first gene that was ever linked to height
Speaker 1: in population. And uh, I'm I'm about an eighth of
Speaker 1: an inch taller than it would be otherwise because of
Speaker 1: the variant that I have, So you know, it's it's
Speaker 1: almost invisible. UM. But you know, the genetic influence just
Speaker 1: is the some of all of these different variants. UM.
Speaker 1: And yet on top of all of that, UM, you know,
Speaker 1: you can have, you know, all the tall genes you want,
Speaker 1: but if you're not getting a good diet when you're
Speaker 1: a kid, and if you're facing dysentery on a regular basis,
Speaker 1: you're just not going to grow that tall because your
Speaker 1: body is going to be basically channeling all those resources
Speaker 1: to fighting disease and to you know, fight defend against starvation.
Speaker 1: And you know, on top of that, even more amazing
Speaker 1: to me is that in the whole world has actually
Speaker 1: gotten several inches taller over the past century because life
Speaker 1: overall is better. You know, there's more people have a
Speaker 1: better nutrition, better medicine. Education probably plays a role in this. Uh.
Speaker 1: And so it's not that people inherited you know, quote
Speaker 1: unquote tall genes, it's that they inherited a world that
Speaker 1: favors greater height. So I've got one last question that
Speaker 1: might be kind of weird, but we'll see what you
Speaker 1: think of it. I often hear hear people talking about
Speaker 1: their relationship with their own genome, um with their own
Speaker 1: genes into 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 mentality. And then there's a kind of antagonistic
Speaker 1: kind of thing people think about with their genes, like
Speaker 1: the genes are this other disembodied force that made them
Speaker 1: and it's almost like another person that they have to
Speaker 1: 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 train 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,
Speaker 1: well that's why I that's why I like to tell stories,
Speaker 1: or 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 gens 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 sequenced 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 Neandertal,
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, like, 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 particular Like, here's one gene, Tell me
Speaker 1: about it, and the scientists be like, well, it looks
Speaker 1: like no one actually knows what this gene does at all,
Speaker 1: you know, and then that you're just left there. But
Speaker 1: with the state of the science, you know, maybe I
Speaker 1: found that I have a neandertal gene that UM is
Speaker 1: linked to an increased risk of nose bleeds. I don't know.
Speaker 1: I don't know what to do with that, you know,
Speaker 1: And it also makes me wonder why neandertals might have nosebleeds.
Speaker 1: But that's a whole separate issue. But you know, 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 like, 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 it stands for me now, all right, yeah, well, well,
Speaker 1: thank you so much, Carl. It's been a real pleasure
Speaker 1: talking to you today, and we appreciate you taking time
Speaker 1: to speak with us. My pleasure, my pleasure. I really
Speaker 1: enjoyed the conversation and I'm 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: audiobook right now, and you can check out Carl's website
Speaker 1: Carl Zimmer dot com for even more about him and
Speaker 1: his projects. That's right, go to that website. And hey,
Speaker 1: be sure to check out our website as well. It's
Speaker 1: Stuff to Blow your Mind dot com. That's who you'll
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