Science Friday - Heredity, Oldest Bread, Jupiter's Moons. July 20, 2018, Part 2

Episode Date: July 20, 2018

Have you ever taken a peek at your family tree? If you trace back along those branches, you might discover some long ago celebrities, kings, and philosophers among your ancestors. But what does it even mean to be “related” to an ancient queen when it’s hard to know what’s lurking inside our own DNA? It turns out even one generation back, the question of who we are gets made complicated. “We’re primed to think of our genomes as some kind of magical book. We just understand so little about genetics. Period.” says Carl Zimmer, author of the new book She Has Her Mother’s Laugh: The Powers, Perversions, and Potential of Heredity. Zimmer joins Ira to discuss Mendel’s Law, the history of eugenics, the power of CRISPR and the boundaries of what we understand of human heredity today. Bread is a staple food today. You can find dozens of varieties at the supermarket—tortillas and pita, naan and focaccia, rye bread and wonder bread and baguettes too. Bread is so ubiquitous that it’s hard to imagine it was once a rare commodity, a labor-intensive specialty that could be made only by husking the seeds of wild grasses, hand-pounding and grinding them, then mixing the resulting flour with water and scorching on a hearth. Archaeologists working at a 14,000-year-old site in Jordan have now found evidence of an early bakery in the form of burned crumbs, similar to the ones at the bottom of your toaster. After analyzing the crumbs’ structure with a scanning electron microscope, the researchers were able to characterize the crumbs as the charred remains of a flatbread, similar to pita, baked with ingredients like wild einkorn wheat, barley, oats, and the roots of an aquatic plant similar to papyrus. They also determined that the crumbs predate the dawn of agriculture. When Galileo first saw Jupiter through a telescope, he also discovered “stars” that would orbit around the planet in the night sky. While Galileo named them the Medicean stars—after his future patron Cosimo II de’ Medici—we know them today as Jupiter’s moons Io, Europa, Ganymede and Callisto. Since Galileo’s initial discovery, astronomers have found dozens more moons around Jupiter, and this week, researchers announced an additional 12 moons, bringing the total number up to a whopping 79. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Later in the hour, we'll get the recipe for a 14,000-year-old Peterbread, which has one very untraditional ingredient. When Galileo first saw Jupiter through a telescope, he noticed stars hanging around the planet. And as he watched those stars, night after night, he realized they were orbiting the planet. We now know these stars are Jupiter's moons.

Io, Europa, Ganymede, Callisto. And since Galileo's discovery, astronomers have found dozens of moons around Jupiter. And now this week they've entered 12 more, bringing Jupiter's moons total to a whopping 79. And here to talk about the discovery is Scott Shepard. He's an astronomer at the Carnegie Institute for Science. They've had questions about Jupiter's moons,

our number 844-8255. you can also tweet us at Sive Frye. Welcome to Science Friday. Thanks. Thanks for having me. How unexpected is this finding? It wasn't too unexpected because our survey, we're doing a survey. It's the deepest, largest survey for outer solar some objects, so we're trying to find things beyond Pluto.

But Jupiter happened to be in our fields as well in March of 2017. And our survey can cover a big area of sky and can go deeper than other surveys have in the past. So we expected we could turn up some new moons because we have an advantage over others that came before us. So you're saying that you didn't set out originally to point your telescope at Jupiter, but it happened to be there, so why not take advantage?

Yeah, yeah. We do our survey every few months throughout the year, and we knew in March of 2017, Jupiter would be near where we were looking, so we decided to make sure Jupiter was in the center of our field, so we could search for moons at the same. same time we're searching for very distant things in the solar system. So how do you know there were moons and not some asteroid or another gigantic space rock?

And what is a moon defined as anyhow? Yeah, that is actually a pretty long process. So March of 2017 is when we did the discovery observations. Then we had to re-observe the objects a few months later. And we re-observed everything that was moving at the same rate that Jupiter was moving. And that suggested it has something to do with Jupiter. And it wasn't until actually of May of 2018 when we figured out finally that 12, of the objects we were following were moons at Jupiter.

Several other objects we were following turned out to be comets or or main belt asteroids. So it did take a year to determine how many moons we had found. And so, so why does Jupiter have so many moons? 79, right? Did it last count? Yeah, so it has 79, and there's two reasons Jupiter has this many moons. One is it's the biggest plan on the solar system, so has a very big sphere of influence where

if something gets too close to it, it can control that and create a moon out of it. A second reason is a lot of these moons we're finding, the moons that we found are outer moons, so they're further away from Jupiter than the Galilean moons are. And we find these in groups a lot of the times. And what we think is there were originally just a few larger parent bodies that were hundreds of kilometers in size, and they've been collisionally broken apart over time. So we're finding a lot of fragments from collisions that have happened in the Jupiter area. Now, this may sound like a little weird question, because, you know, most of us are used to looking at one moon out in the night sky around our planet.

Are all the moons orbiting the same way? Yeah, and not all of Jupiter's moons orbit the same way. The Galilean moons, which we believe formed with Jupiter, go around Jupiter, they orbit Jupiter in the same direction that Jupiter spins. And we have two different outer kind of groups. We have the pro-grade group, which does the same as the Galangans. They go around Jupiter, the same direction Jupiter spins, and those are about 10 million kilometers from Jupiter.

And then beyond those, we have what we call the retrograde group, and they go on the opposite direction that Jupiter spins. And so we have these two outer groups that go in different directions. And one of the new objects we found actually doesn't obey those two laws. It's actually a prograde object that's in the retrograde group. So it's going down the highway in the wrong direction, which suggests it probably has collided with head-on with some of these retrograde objects in the past.

Does it have a weird shape that would tell you that? We don't know the exact shape, but it's very small. It's the smallest moon we found around Jupiter. It's about one kilometer in size. So it's probably very irregular in shape. It was probably actually bigger in the past. It was probably 10 to 100 kilometers in size, but it's been ground down to mostly dust through collisions over the age of solar system.

So what we see today is probably the remnant of a once bigger moon out there. We have a tweet coming in from Heather Hill who says, do any of Jupiter's moons seem to have an atmosphere? The Galilean moons can hold on to some very tenuous atmospheres, but nothing thick. The only moon that really has an atmosphere in our solar system is Titan, and that's around the size. Our number 844-724-8255 is our number if you'd like to join us.

Let's go to the phones. Let's go to Matthew and Pittsburgh. Hi, Matthew. Hi, how's it going? Hi there. Go ahead. So I was wondering why the four Galilean moons look so different from each other and whether these new moons are also that diverse.

Good question. Yeah, it's a good question. So the Galilean moons look different because they've had. quite different histories. I.O. or EO, it's been called either way, is the closest one to Jupiter, and it's being tidily flex. It's very close to Jupiter, so it gets pulled by Jupiter, but also gets pulled by the further out Galang satellites as well. So it's kind of like if you take a rubber band and stretch it back and forth, it gets really hot. So I.O. gets very hot inside because it's getting stretched back and forth, and that's why it actually has all these volcanoes we find

on it. It's the most active volcano object in our solar system. And so, So that completely changes its surface composition to suffer because of all these volcanoes. Whereas the furthest one out of the Galileans, Callisto, is very far out there. And it's mostly mostly ice because it's so cold. And it's for these two different reasons. One's much further away, it's much colder. The other one's getting entirely stretched that you see quite differences on the surfaces of the Galilean moons. If Jupiter has so many moons, I have 79, and then the next planet next to it, Saturn, has all these rings,

which are actually like like thousands of gazillions of tiny little moons running around, right? Why has one, you know, got rings and why has one got little planet, little moons around it? Yeah, so Jupiter actually has rings as well, but they're very tenuous and they're very close to Jupiter. And Jupiter's rings actually come from. It has four very small inner moons that are closer to Jupiter than the Galilean moons are. And these get bombarded by micrometeorites. Like if you, it's kind of like if you go out in night and you see, a meteorite in Earth's atmosphere, those things are raining down on these small moons all the time

next to Jupiter. And when they hit the surfaces, these very small moons, these are only a few a tens to 100 kilometers in size. They release particles off the surface of the moons, and those particles escape, and they start orbiting around Jupiter. So Jupiter has rings from that process as well. Saturn's rings are probably quite different. We believe we didn't know if they were very old or fairly new, and when I say new, I'm talking 10 to 100 millions of years old. But it looks like from Cassini data that came in over the last few months, Saturn's rings are new, newer than we thought. And so they could be a broken-up moon, some kind of recent broken-up moon. But that's still to be determined exactly where Saturn's rings came from.

Hey, a lot of tweets are coming, and let me get one from Joshua, who says, if Earth had more than one moon, how would it affect tides? Yeah, so Earth is special because we have one moon, and it kind of stabilizes Earth's rotation access. So it's kind of important for life on Earth because if our rotation access was able to move around, that wouldn't be a good thing. Yeah, so if we had another moon, at sometimes those two moons could align with each other be on the same side of the Earth, and tides would even be greater. And then sometimes those two moons would be on the opposite side of Earth, and they could cancel each other out. So, yeah, it would be a quite different tide system here on Earth if we had more than one significant moon. Do you think, then, that one moon is significant for the development of life on Earth?

A lot of people think a moon is very helpful for a planet because it stabilizes the rotation axis of the planet. And so currently the Earth's rotation axis is 23.5 degrees inclined, and it more or less stays near that number. and so that the seasons on Earth are very constant, very similar every year to year. But if you let that rotation axis vary, the seasons could get much harsher at other times if the rotation axis changes. And so that would be pretty bad for life here on Earth. Andrea tweets are, are they newly discovered or newly formed? The moons around Jupiter are newly discovered. We believe they've been there since Jupiter formed about 4.5 billion years ago.

And the ones that we discovered, these outer moons, we don't believe they formed with Jupiter. We actually think they were captured by Jupiter during its formation process. Jupiter cannot currently capture moons very efficiently because you need to somehow slow an object down to capture it. You need to dissipate energy from its orbit, and that currently doesn't exist. But when Jupiter was forming, there was a lot of gas and dust in the system, and that could slow an object down and allow it to be captured. Alan tweets, why are planets and moons always circular? So the biggest ones are circular. If you ever seen an astronaut in space and you see them throw water out in a non-zero-gravity environment, that water ball will go to a sphere because that's the least amount of energy for an object to have.

And so if you have a very big object where gravity dominates, it's got to turn into a sphere because that's the least amount of energy for the object to have. But these moons that we found are small. They're only a few kilometers in size, and they're likely not spherical. They're probably very elongated. or regular-shaped bodies because their surface tension, the material strength of the body is probably stronger than gravity is, and so they can keep these elongated shapes over gravity. So they're too small to be like Europa, which might have oceans or things on it. Yeah, so all the Galileans are very spherical

because they're very big objects. Ganymede, the largest moon in our source, is bigger than the planet Mercury. So that just shows you how big some of these galileans are. I want to get one quick question before we have to go about your search for planet nine. How's it going? Yeah, so our main goal is to find dwarf planets and planets beyond Pluto.

We call them way, way out there objects. And we've covered about 20% of the sky we wanted to cover, so we're still doing that survey. We found several new dwarf planet-type objects that we're tracking, and hopefully the more we find in these small objects, they can lead us to a bigger object due to its signature on the orbits of the smaller objects. So you're very hopeful you're going to still find it? We think it's more likely than not that this planet beyond Pluto exists,

but it's not a guaranteed thing, and that's kind of what in the next few years we hope to determine. Can you train your telescope on another planet looking for more moons, or would you suspect there are more there around Jupiter? We just haven't seen them. If there's 79, might not 179. Yeah, so we've actually checked in the last year or two. We've checked all the planets,

and Jupiter was the one where we haven't gone to extreme faint magnitude, stream depths for the very small ones yet, just because its sphere of influence is so big, it's hard to cover the whole area around Jupiter. But we're using the largest wide-field camera and a large-class telescope in the world that only was put on a telescope in the last few years. So we have a big advantage over people in the past,

and that's why Jupiter was so successful. Scott Chepard, thank you for, this fascinating, for taking a tap to talk with us today. Thanks for having me. You're welcome, Scott Chepard, an astronomer at the Carnegie Institution for Science. We're going to take a break, and when we come back, Emperor Charlemagne,

How much do we really know about what's lurking in our DNA? Is it possible we could be related to Charlemagne? Maybe Cleopatra. Carl Zimmer is here with his new book to talk about it. We'll be right back after this break. This is Science Friday. I'm Ira Plato. Have you ever taken a peek at your family tree?

How many branches does it have? Trace your ancestral line back along those infinitely dividing branches, and you might discover that you are related to Emperor Shepard. Charlemagne. And if you go even further back, you might run into Cleopatra, a direct ancestor, perhaps, of all living humans. I know it's hard to wrap your mind around that, but the math of genetics says it's true. But what does it mean to be related to the Egyptian queen? And what does the term meiosis mean? Where does the idea of race come from? And what does CRISPR do again exactly? And why is an under attack this week? Well, my next guest says it's okay that we still have these

questions. The field of genetics, the study of inheritance is growing and developing so quickly that, you know, it is hard to keep up. Well, luckily, he's compiled what we know so far into his latest book. So if you have questions about genetics or heredity, I'm certain the answer must be contained in these pages if there is an answer, that is, and there are a lot of pages in this book. If you want to talk to Carl Zimmer, science columnist for the New York Times, an author of the new book, She Has Her Mother's Laugh. Give us a call 844-724-8255-8-4-4-Side Talk. Nice to see you again, Carl.

It's great to be here. The synthesis for she has her mother's laugh. Why did you call it that and what was the idea behind it? Well, I have been thinking a lot recently about how much we use heredity to define who we are. And we're always thinking about it and we're looking back at our ancestors or those of us who have kids. or looking at our kids and wondering, you know, what do they have of us in them? And, you know, people will say things like, well, she has her mother's laugh. You know, and what does that really mean?

It's something that we seize on, but, and yet I think it's worth diving deeper and understanding what really is heredity and why is it so important to us? And what can science tell us about what heredity may actually be? So what is the difference between heredity and genetics then? Well, genetics was a science that was founded to answer the question of heredity. I mean, people have been wondering about heredity for a very long time, and they've been able to see the effects of heredity for a very long time. And they had various vague ideas about why that was so.

But in the early 1900s, a group of scientists rediscovered this work by some obscure monk named Gregor Mendel, and they said, aha, I think we're on to something here. And they found out a science called genetics, and what they said was the science of heredity has now been revolutionized. They thought they had it all figured out. And then they created tools to change the whole thing, to experiment with the genetics, right? That's right. That's right. I remember, I mean, one of the first things I did as a young science reporter back in the 70s was cover the Assyllamar Conference, right? Which we knew how to create these genetic engineering tools.

And then people were worried, hey, what can we create that might crawl out of the laboratory? we should stop and talk about this. Right. And there you were talking about basically taking some DNA from one species and sticking in another. Pretty crude. Now we're talking about things like CRISPR where basically you can rewrite the DNA of that species and maybe be able to write whatever you want. And we talk a lot about CRISPR on this program.

And we were thinking about talking about the CRISPR issue this week that came out. I thought, I'd say that for Carl Zimmer, he'll be able to explain it to us. There's some problem that has developed in CRISPR. Tell us about that. Well, the basic idea with CRISPR is that you design molecules that can zero in on a particular spot in DNA, cut it, and then if you want, you can replace what you cut with some new DNA. And this might be a way to treat disease. It's already proving to be a way to create new varieties of crops because these changes are then inherited. This is a way of changing heredity.

But there have been some questions about whether this is going to be safe and reliable and precise. And just this week there was a study that suggested that it could be possible to cut out the DNA that you wanted to cut, but maybe cut a lot of other DNA right around it. And if you cut out an essential gene while you're trying to rewrite something else, you've got problems. Because there are people who are waiting standing by to have to. crisp bread is an experiment. There are clinical trials that could be ready to go

now. They're spring-loaded, you know? I mean, for like sickle cell anemia. Like this could really revolutionize medicine, but we've got to make sure that it's safe. Let's talk about, delve into your book a little bit more.

There's so much history in the story of genetics, and you take us through a number of the characters. Who has who would you say as someone who has influenced the field that maybe we haven't heard of who is influential in this. You mentioned Mendel. We've all heard of Mendel. Right. Well, you know, there are lots of people who have been long been forgotten. So, for example, there was a sheep breeder in the 1700s named Bakewell who actually created an entirely new breed of sheep, the new Lester, and people were amazed. Like, how did he do that?

How was that possible? And what he had been doing was he'd actually been very carefully breeding these sheep and bringing in sheep from other farms, and he would take them into these barns where no one could see what he was doing. It was almost like magic. So one noble woman referred to him as the man who invented sheep. And he inspired so many people. Darwin was completely obsessed with how he had created a new breed of sheep, and he influenced Gregor Mendel.

And yet, you know, the story of people like him get forgotten because we have a very, we have a kind a simplistic view of genetics and heredity and how it was all figured out. But it's actually the history is really fascinating. And it was a really interesting part that you mentioned, forgotten in history, because over the years, as someone who's read a lot about, you know, heredity and about genetics, I remember reading way back, I'm sure you read the same stuff, about eugenics starting with the Nazis. And I'm reading in your book and you're saying, no, it didn't originate. With Emigos further back, which I hadn't heard about. Yeah, no, I mean, if you want to look for a place where eugenics really got off the ground,

I mean, one place that I write about a lot in the book is Vineland, New Jersey, a town in southern New Jersey where there was a school for the quote-unquote feeble-minded, and there was a psychologist there who introduced intelligence testing in the early 1900s and became convinced that feeble-mindedness was completely hereditary and created these great big family trees to prove it. And that led to legislation for sterilizing people in the United States. And then the Nazis took a look at this kind of eugenics in the United States and borrowed a lot of their rhetoric. Let me get out of the way because I'm getting questions about this because I did mention that.

We could probably all trace our history back to Cleopatra. How can we all have her as a common ancestor? Well, it's just the geometrical properties of our family trees. You know, like, you think about your family tree and it's you, and then it branches to your parents and then their grandparents. Now, if you just kept branching it like that forever, it wouldn't take very long before you had more ancestors than humans who have ever lived. So actually, your parents are not totally unrelated. They're cousins. So really, if you were to trace their ancestry back far enough, you'd get to a common ancestor of them. And that's true for all of us.

And you can actually look at the shape of the family tree just based on mathematical analysis. And you can prove that if you go back a few thousand years, if there's somebody who is alive then, who has a living descendant today, they must be the ancestor of all living people today. Oh. You generate that through a mathematical proof. You don't have to go and look at everyone's DNA.

That just comes out of the nature of our genealogy. Now, speaking of genealogy, I know you got your genome sequenced while writing this, you've got your whole genome. It wasn't like sending a little spit in a tube to somebody, right? Right, right. It was like a thousand times more than 23 me, basically. And so were you surprised about what you learned?

I was relieved that I didn't discover anything horrific in there. But once I sort of passed that, then it's like, okay, well, what now? So I got hold of the raw data and took it to various scientists and said, show me how you study genomes by looking at mine. and tell me what you can find in there. For example, I got a complete list of my Neanderthal genes, which was fascinating. Really? Yeah.

Well, you know, people who have ancestry outside of Africa are all around 1% Neanderthal. But we inherit different fragments of Neanderthal DNA from interbreeding that happened maybe 60,000, 70,000 years ago. So you have Neanderthal DNA. I have it, but we probably don't have the same. Now, mine, I've discovered, some of my genes have been a... associated with a risk of nosebleeds. I don't know why Neanderthals will get nosebleeds, but, you know, and people who have it today,

they're at a slightly elevated risk of nosebleeds. 8447248255. 8447248255 is a number. You can also tweet us at SciFRI. I remember because I've been around for a lot of the talks as genetic engineering and genes and heredity have been going on over the years. the early ideas about genes, at least in the modern day, was that there's going to be a gene that tells us about everything.

One gene, one trait. There's going to be an intelligence gene. It's going to be a gene for sex, for gender. That has not panned out, has it? No, absolutely not. I mean, that was kind of a low-hanging fruit. You know, your blood type. Yeah, one gene, sure.

But beyond that, you know, something like height, for example. Height seems simple, right? It's just, you know, you just take a tape measure to measure it. It turns out that height has been linked now to about 3,000 different genes, 3,000 different sites in our DNA that there are variants that influence how tall we get. And scientists are going to find thousands of more they expect. So even something as simple as height is influenced by all sorts of parts of our genome. And so, you know, there are genetic influences on things like our personality and intelligence.

But again, that influence is going to be so complicated. It's going to take a long time to sort out. The tweets are coming in from what you're talking about here. Ray says, no way a lost tribe from the Amazon is directly related to Cleopatra. Ask him. Look, what can I tell you? I mean, you can think about, well, all these people have been isolated. But, like, really, it only just takes one person to make contact with a group of people to connect family trees together.

And then, you know, over future generations, those family trees get more and more connected. I know it sounds very counterintuitive, but, you know, it just, that's the, it would be impossible for it to be otherwise. And you mentioned Charlemagne before. I mean, Charlemagne lived more recently, but if you look actually in Europe, you can be pretty confident that all living Europeans are probably a direct ancestor, a descendant of Charlemagne. So, you know, what I think is interesting about all that is that it, you know, it kind of shows that we shouldn't like try to make ourselves feel very special by finding a famous ancestor because we have a lot of company. 844-724-8255. You know, we are constantly balancing our nature versus nurture discussion, right? I'm sure you're familiar with it.

But does epigenetics, the factors in the environment that influence the expression of, of genes cloud that debate or does it crystallize that debate? And, you know, Lamarck, you know where I'm going with this. You know, we all talk about Darwin, but Lamarck had his counter views that the environment somehow influenced what happened. Could he be making a little bit of comeback with epigenetics here? Somehow the environment influencing, how genes are expressed and that's carried through? So I think epigenetics is one of the most fascinating aspects of heredity now.

I have a whole chapter where I talk about it. And what makes it so fascinating is the prospect that maybe experience can be passed down. I mean, maybe that can influence future generations. And, you know, there is really solid evidence in some species in plants and certain species of animals. When it comes to mammals and especially humans, I would say that the evidence is much, much murkier. Part of that's because we still don't really understand how epigenetics really works. It is really very much the frontier of biology. But it's exciting because it does raise these possibilities that what happens in your life might affect your grandchildren.

I'm Ira Flato. This is Science Friday from WNYC Studios. Talking with Carl Zimmer, science columnist for the New York Times, an author of the new book. she has her mother's laugh. Don't be, you know, lulled into complacency by that, by the title, because this book is chock full of all kinds of interesting stuff and it's 600 pages. Any question you've ever wanted, how did you limit to 600 pages? There are so many great stories. And I mean, I would, and I would just, I would just, I would discover new people and just, I'd just be so fascinated by them. people who figure prominently in the history of Redity or people who are doing science right now.

It was just so much fun to write this. So here's a tweet coming in, says, do you suppose there are more subtle hereditary things like the preference for art or music or the seaside or food or stuff like that? Well, I think that you could... If you could have your mother's laugh, why can't you have those? Well, you know, it's going to be hard for you to dissect that. like, do you have a thing for art because your parents took you to museums all the time or because there were some art gene? Like, how would you know the difference?

I mean, that's the real challenge with trying to figure out what it means for you as an individual. But what scientists do is they study entire populations and try to see, like, well, how do we account for the differences? So are relatives more similar than you'd expect compared to other people? And you know what the fact is with things having to do with, well, you know, divorce, you can actually argue is what scientists call heritable. You know, that likelihood of divorce is more similar if you're related than not. That doesn't mean there's a divorce gene. That means that there might be genes that influence your behavior in very subtle ways that we don't understand at all. And then maybe in certain situations, tip the balance a little towards taking a certain decision.

But we're so far from really having a grasp of that that it's just pure speculation. Yeah, because people, as they say, going back to the early days when we wanted to find one gene, people were looking for that single gene, you know, for either homosexuality or it's sports or something like that. Yeah, and you have to remember that genes aren't like people. They don't do things. They're just sitting there. And the effects that they have depend on your environment. So there can be genes.

you know, I have a gene I discovered getting my genome sequence that actually on average makes people a few pounds heavier than they would be without it. And I have two copies, one from each parent. And, you know, the fact is that for people who were born in the 1940s or earlier, it doesn't have that effect at all. And it probably just has to do with the fact that, you know, people of my generation are growing up in this crazy diet environment where we can eat all the sugar. and carbohydrates we want. And that just wasn't true before. And now that gene is becoming a risk for weight gain and obesity.

Yeah. Well, I'm going to talk more with Carl Zimmer after the break. He's a science columnist for The Times, an author of the new book. She has her mother's laugh. If you don't want to get in on the conversation, a number is 844-724-8255. Also, you can tweet us at Cy Fry. We'll be right back after this break.

Stay with us. This is Science Friday. I'm Ira Flato. talking with Carl Zimmer, author of the new book. She has her mother's laugh about the science of heredity. And you can give us a call. 844-8-8-255. Let me see.

We've got some calls and some tweets. Let me go to the tweets. I know this is going to be a hard one for you to answer. How would you go about? How do I go about getting my entire genome sequence Donald wants to know? You're a reporter. You could do it a little easier than most people, right? So I did it through a program that, actually, I don't think no longer,

exists. I think they discontinued it just a few weeks ago. But there are some companies. There's one called Veritas. There's another company called Helix that you might want to look into. Now, these places will sequence your genome, but I'm not clear on whether they will actually let you have the raw data. In other words, they'll look at it and tell you all about it. But if you want to play around with it yourself, that can be a challenge because genome sequencing is kind of in a gray zone right now. And there's a lot of questions about, well, about liability because genome sequencing is not a precise science. You know, it's rough and there's a lot of error correction that has to go into giving you an analysis. And so if somebody just gives you the raw data and you misread it and

think that you have inherited a gene for some incredible disease that you don't have, or or you think you're safe from some disease and you go sue them, whoo, it could be trouble. A couple of months back, the Golden State Killer brought up questions about this privacy issue for people using these family tree databases. Do you think these new tools are we opening up a Pandora's box, especially you, if you get your total genome sequence, could it leak out? We know you now are susceptible to nosebleeds. Yeah. I mean, could that bite you a little bit later from a, you know, insurance firm or something? I did, I have put my whole genome online.

Right. Anybody can take it. Scary, I would. I don't know. I'm personally okay with it. But, and, you know, a scientist who I worked with said, like, hey, this would actually be a cool teaching tool. So we're actually using my genome and analysis of it in a class at Yale where every year these students take a look at my genome and try to find something interesting. But, you know, I had the choice there.

And so I think it's important that people have control over their genetic influence. information. And, you know, if somebody uploads their own information about their DNA to one of these genealogy sites, you know, in a way, you're actually sharing, you know, some of your siblings' DNA or your cousins because you share a lot of identical stretches of DNA. And that's, we saw that with the Golden State Killer. Like, the only reason that a person was arrested is because his, some of his DNA matched some of his cousins. Let's go to the phones. Let's go to Stephen in Dalton, Ohio. Hi, Stephen. Welcome to Science Friday. It's in Dayton, Ohio. Oh, I'm sorry.

No problem. My question is about the mutability. They're just flying overhead right now. The question I have is about the mutability of the genome in regard to environmental stressors, about turning on or turning off genes. How does the environment turn on or off the genes? How does epigenetics work? Well, basically, you know, you have the same set of genes, basically in all your cells.

But obviously, you know, a skin cell is a lot different than a cell in your brain, and they do different things. And the reason is because they are keeping certain cells shut down and certain ones turned on. And they started doing that when you were an embryo, and that has continued ever since. But on the other hand, we do have genes that we use to respond to things in the environment, and we have switches that can turn them on, and then in some cases keep them on. And so there can be experiences early in life that may possibly be able to trigger long-term changes that stay that way later in life in ourselves. And so this might be an explanation for how experiences early in life can have effect

decades later in terms of your health and behavior and so on. So, you know, we need to be able to respond to the environment, and epigenetics seems to be a really important part of that connection. And we're thinking maybe some of those epigenetic changes can be passed down, perhaps, from generation to generation? So that's the big question is, like, could somehow epigenetic changes in your own body get passed down to the next generation? Obviously, they would have to get into sperm and eggs,

and then they would have to survive into that embryo and then the next generation. And I don't think that the evidence is really there for our species. For some other species, yes, which is fascinating. This is a fascinating book. We've just scratched the surface with Carl Zimmer, author of She Has Her Mother's Laugh

about the Science of Heredity. It's a great, great piece of work. That's why I can see a lot of work went into that, Carl. Thank you for taking time to be with us today. Thanks so much. Our next subject is about bread. Bread is such a staple food today, and every culture has their own. There's tortillas and pita and nan and faccacho, rye, wonderbread baguettes.

Bread is so ubiquitous, and it's hard to imagine it was once a rare commodity of food for special occasions, maybe. We could only make it with a lot of hard work, husking, hand-pounding, wild grass seeds. Archaeologists working in Jordan have now found the burned sort of toaster crumbs of an ancient batch of bread, a primitive pita that predates even the dawn of agriculture. Here to give us the recipe as Amai Aronza Otaegi, he's a postdoctoral researcher in archaeobotany. I don't think we've ever used that word before. Archaeobotany at the University of Copenhagen in Denmark and published a detailed ingredient list of that bread this week in the proceedings of the National Academy of Sciences. And she joins us by Skype from Iran.

Welcome to Science Friday. Hello. Okay. How many crumbs did you find? Well, we found more than 600, actually, but we only have analyzed like 24, so we still have a lot of work to do in the future. Why didn't anyone see any crumbs before? That's a good question. Well, because as an archaeologist, I think we have always focused on, you know,

architecture, pottery, bones, flint, and all these big things, right, that we can see with our naked eyes. And small things like seeds and food remains have been long ignored. So I think that this paper will help, you know, will help improving the visibility of this long, ignored remains. And so once you got hold of the crumbs, you put them under an electron microscope. and we have a photo of that microscopic bread structure on our website at Science Friday.com slash bread. But once you looked at the structure, what did you find? So when we look at the structures, when we look at the food remains under the microscope, we see two things.

We see on the one hand we see plant particles, plant tissues microscopic, very small, that inform us on the ingredients of the food. And then we also see the texture, right? and if you see that image that it's in the website, you will see that it's very porous, right? Very similar to bread. So these two things are giving us the ingredients and the food product, like the final product.

Yeah. To, you know, to know. So give us the recipe. What are the ingredients in this bread? Well, it's not easy, actually. It's a multi-seated or multi-ingred, I would say. So it has some cereals. We know that these people were using wheat

and we're using barley and oat, for example. All of them were wild species that were growing naturally in the area. And then they are using something quite interesting, which are chevers, which are the part of the plant that grows under the ground, like a root. So they were using a plant that grows in lakes and it's an aquatic plant of the family of Papyrus,

and they were using these tubers to make a flower with them. So I think it's an exciting thing to see, actually, because tubers have also been ignored in archaeology, so it's good to see these evidence, actually. Did it take a lot of work to make this bread? Well, for them, it must have been a really hard work. First, because they had to find the ingredients, especially cereals.

We don't really know where they were growing at that time. The chevers, this club rush chevers, must have been growing quite close to the site. But the cedias, we don't really know. So imagine that they have to find them. They have to walk perhaps, you know, tens of kilometers to find them. And then they have to harvest them and then process them, which is, you know, the husking. All these wild cidias is a very hard work, actually. The grains are very well protected.

it. It's not like the wheat we have nowadays that it's very easily, you know, processed. So the grains are really easily released from the plant. But this wild species were really, really well protected. So it must have been a really hard work for them. And then, of course, they had to make the flour. So grind the cereals, grind the truvers, and then, you know, make dough and bake it. So it must have been quite, you know, some hard work. You know, I know that we say aggregate. This is, 14,000-year-old bread, and I'm blown away by the fact that there's still parts of it left over that haven't oxidizer. They just haven't disintegrated. No.

But besides that, we know we think that agriculture, at least farming, came years and years later after this. So you're saying there's a hunter-gatherers who just would go out and find the wild grains growing. They're not. I guess I'm asking, maybe we should move that timeline back. So agriculture, and you're saying no, they were just wild gatherers? Yeah, they were wild gatherers. Yes, that's something that we know for sure, actually. We know that they were not cultivating these cereals at this site.

And cultivation comes like, let's say, 2,000 or 3,000 years later. Well, that's for now, you know. Well, that's what I'm asking. Maybe that timeline is wrong. I mean, you're making a discovery, and maybe, you know, We've heard this numerous times about Neanderthals, all kinds of discoveries. We've moved the timelines back and forth. I mean, which is the evidence and which is the symptom, you know?

Yeah, the thing with the cedials is that when we look at the seats, we actually are able to see that they're morphologically wild. So we know that these wild plants were reproducing by themselves. So that's for sure. And when we look at this site, we also found this wild cereal. So we know that they are not domesticated at all. So that's something that we know. But the question is, like, why they were doing bread and why they were using these cidias

and why they were taking all this work to do bread? So that's a big question that we would like to answer in the future. Amira Flato. This is Science Friday from WNYC Studios. talking with Amaya Aranzoateegi, who is a post hoc researcher in archaeobotany at the University of Copenhagen. Why do you question this? I mean, what is there about? Is it just so labor intensive you're saying that you would have to spend so much time making the bread that maybe you should have been hunting something else that might be easier?

You're using up a lot of energy for that calories you're getting? Yeah, we think so. We think that it must have been easier. to, for example, the tubers, we know that they were using these tubers that were at hand. You know, they were very close to sod and they are quite easy to process. So we know they were using those. But why were they using the CDias that are really time-consuming to process? So there are some, you know, there are some researchers that say that products like bread and beer could have been something special, you know, something that you all.

only consume in a specific, you know, occasions or, you know, ceremonies or fistings and things like that. So that's something that we would like to explore, you know, because that's a possibility. And yeah, I know that, you know, there are some authors, actually some from the States like Brian Hyden that suggest this type of, you know, hypothesis. So I think they are actually very happy with our evidence to see that,

you know, bread was made before agriculture. You know, because I'm looking at a Science Friday.com Slate, bread. I'm looking at the photos on our website of what was discovered. And this was a very well laid out oven and processing place there. This wasn't just something haphazard, you know, that they had a rock bowl on a rock. This was not that. This was, so that's what makes me think that this, you know, they used this more than just occasionally. Yeah. Actually, I mean, the site itself is quite special. If you, if we look at the, at the, you know, at the fireplaces, yeah, two of them, they are huge. They are like one meter, you know, in diameter, very big, and they have tons of

food in there. They were gazelle, they were hares, they were sheep, there were birds, they were all these chevers, thousands of them, more than 65,000 plant remains that I found. So there was a lot of food in these fireplaces. And the structure. actually itself is not that large. You know, we tried to feed like 20, not 20, maybe 15 people inside the structure. And we think like, okay, this was like too much food for 15 people. So we don't really know, but it's an interesting site. And we would like to continue and see what, you know, what their research tell us.

You know, some, right now you have n equals 1 sites. Would you be looking for more sites to figure out? to figure out, you know, gather more data? Absolutely. I think that's what we need to do. Actually, in this area where we are working, it's a black desert. Imagine like a desert with a black carpet of, you know, stones, basalt stones. There is nothing nowadays.

But that's very good for us because the preservation of the sites is incredible. There are many sites around this one. And we are actually digging them. So we have another site, which is a, called Cheveka 6, which also dates to this time period and continues. So it goes into the next 2000, 3,000 years. So I think this one is going to give us more evidence to confirm our hypothesis. And the Iranian government's very happy with you working there. Well, I don't know. I don't know. I haven't asked them. We won't tell them that you're there, okay?

Yeah, all right. You better. Yeah, you better. Thank you very much for taking time to be with us and stand up so late for us. Amaya Ronsotahegi is a postdoctoral researcher in Arcoeo Botany at the University of Copenhagen in Denmark. BJ Leiderman composed our theme music. If you missed any part of our program, of course, you can subscribe to our podcast. You can also ask any of your smart speakers to play Science Friday. You can hear Science Friday, you know, five days, seven days a week, if you like.

Every day is Science Friday. And, of course, we're active on all social media, Facebook, Twitter, Instagram. If you'd like to send this email, you can send email SciFri at ScienceFriety.com, and we'd be happy to talk to you. Have a great weekend. We'll see you next week. I'm Ira Flato in New York.