Science Friday - Gene-Editing Humans, Asymmetry, Ancient Whale Ancestor. Nov 30, 2018, Part 2

Episode Date: November 30, 2018

The first CRISPR-edited babies are (probably) here. The news raises social, ethical, and regulatory questions—for both scientists and society. Then, why are human bodies asymmetrical? A single protein could help explain why. And finally, ever wondered how whales got their mouth bristles? It's possible that they went through a phase where they sucked up their food like vacuums before they evolved baleen. 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. This week, a Chinese scientist made a stunning announcement. He claimed to have used CRISPR to edit the genome of embryos to alter a gene that plays a role in HIV infection. And then twin girls were born earlier this month from these embryos and their maybe more babies. The Chinese government halted research in this area and the Committee of the Second International Summit on Hewerews. human genome editing, which happened this week in Hong Kong, released a statement that said, quote, it would be irresponsible to proceed with any clinical use of heritable germline. Is this taking CRISPR too far?

What are some of the ethical, social, and regulatory ideas that we should be thinking as gene editing technology moves forward? Where would you draw the line with gene editing? What questions do you have about CRISPR and what it's? can do. We want to hear from you. Our number, 844-724-8255. That's 844-724-8255. You can also tweet us at SciFri. That's what we're going to be talking about with my next guess. Josephine Johnston is a bioethicist and director of research at the Hastings Center in Garrison, New York. Welcome to Science Friday. Thanks for helping me back. You're welcome. Paula Cannon is a professor of molecular

microbiology and immunology at the Keck School of Medicine. That's at the University of Southern California in Los Angeles. Welcome to Science Friday. Hello, Ira. And as I say, number 844-724-8255 if you would like to chime in. Paula, the scientist, doctor, he did not publish a study or show the data, so right now it's still a claim, but you think he actually did gene edit these kids? I think so, yes.

certainly from the data he's presented, if one assumes he isn't falsifying anything, it looks pretty compelling to me that he has done what he's claimed to do. But of course, I'm going to wait to see the actual data when he submits it and indeed when it gets published. But I think most people would probably think that he has done what he's claimed to do. Josephine, you know, CRISPR hasn't been around for that long. Were you surprised that this happened? Not that it happened at all, but I wasn't expecting it to happen this week or even really this year. So it does seem like the kind of thing that you know certain people are going to want to try to do,

but I hadn't been expecting it yet because the safety questions do seem rather large and that makes using it to create children seem quite risky. Well, let me ask you about that because what line was crossed here? I mean, because this type of research being done in embryos is done all the time. What was the line, the ethical line that was crossed? So there has been some research using CRISPR in human embryos, but not embryos that would then transfer to a woman's body for gestation and birth. Like they were in a lab, they were laboratory research.

And this is as far as I know, the only time that anyone has actually taken the embryos that have been edited with CRISPR and actually tried to generate a pregnancy out of them. and there's no other known cases of that in the public domain. So there were really two lines crossed at least. One is that pretty much everybody that I've heard comment on this agrees that one of the lines is that he prematurely leapt into a clinical use to create babies so that that's like just going far too quickly. And you said it was how farward should we go with CRISPR,

but the other question is how fast. And he prematurely moved into clinical research. And most people I've heard, comments agree about that. The other line is a little different and the other line is doing what's called a germline change. So making a change that can be inherited, that can be passed

on generation to generation. And that's another line in the sand that a lot of people and a lot of countries actually think it should not be crossed. And so that's the sort of second way in which this was big news. Let me ask Dr. Cannon, why would he cross that line? And if no one else

is doing it, why would he do that? Oh gosh. You have to ask him. wouldn't you? I mean, I think the line that he crossed, I think I want to stress that it wasn't really that much of a technical line. You know, this sort of embryo editing using CRISPR had already been demonstrated

in multiple different animals, including, you know, producing edited monkeys, for example, and we'd already seen that people had developed the technology to edit embryos that had not been transplanted. So the technical line

that he crossed, if you like, was a relatively small step of then taking those edited human embryos and implanting it into a woman. Why he chose to do that, you know, his, you know, having listened to his explanation, he really seems to think that he's doing something for the good of humankind, that he's trailblazing that this needs to be done, and he is demonstrating in his mind, I think, that this can be done safely. Well, we won't, we don't know if it's safe, safely done. Do we not? No, absolutely not. You know, there's a number of things to consider when you think about safety. First of all, the technology, the goal is to change in this case one gene, but we know that although CRISPR can be highly accurate, it's not 100% accurate.

And so there is always the risk that there will be other genes that are, you know, by accident changed at the same time. and we don't know what the consequences of those could be. And in addition, you know, Dr. He chose this gene CCR-5 for what I think were very, you know, not-convincing reasons. And I think one of the reasons he chose that is because certain people, about 1% of the population, mostly Europeans, naturally don't have this gene. So the idea that he could, you know, knock it out or destroy it, in these embryos, you know, he would argue that that was an innocuous change, but I really think

that that has not been definitively shown at all. So on a number of levels, the, you know, the safety really was not yet demonstrated. Dr. Johnson, would you agree? That is my understanding. I'm not a scientist or a clinician, so assessing the safety is not my forte, but everything I have heard says the same thing. And it showed a question for Dr. Cannon because I also heard that people without CCR5 are more susceptible to the flu. Is that true? And if so, that makes the trade-off even more, sort of less convincing.

Yeah, no, that's definitely some consideration about what not having CCR-5 might do to you. While it's clearly associated with being profoundly, although not completely resistant to HIV, which was the positive attribute, if you like, that Dr. He was going after. This is a molecule that's important for a lot of the way that our immune system responds to viruses. And for example, people who naturally don't have CCR5 are much more likely to have a bad outcome if they're infected with certain viruses. The most significant one that I know of is West Nile virus, which most of the time causes an asymptomatic infection. But people who don't have CCR5 are much more at risk of having. a very devastating neurological complications from this disease.

And certainly I've also heard the flu story, although I think that's only been demonstrated really convincingly in mice that have been engineered not to have CCR5. Dr. Cannon, what are the guidelines in place here in the United States right now about using CRISPR and embryos? Sure. So there's multiple levels where this is regulated. You know, the United States, along with, you know, many nations have just guidelines,

lines in general about how you could do any sort of experimentation, if you like, on humans at any stage of their life. And, you know, when we have even new drugs or new therapies, you first of all have to get approval at multiple levels. First of all, from the FDA. And then secondly, within your own institution, there will be a board referred to as the Institutional Review Board, which is typically a group of clinicians, scientists, and members of the community that also evaluates whether what you're doing is safe and appropriate. And with the special case of doing any sort of genetic manipulation, including gene editing, the United States also has a review body called the Recombinant DNA Advisory Committee that looks at this. So multiple, multiple levels. Dr. Johnston, can you get international consensus on?

of these guidelines? Well, there's, so it depends how many countries you want in your group in order to say you have it, but there's been a good amount of international consensus on research ethics, on how to do research in humans and what the appropriate safeguards need to be. I think that the summary statement from the World Summit that just happened in Hong Kong, which is the second, the first summit being in D.C. in 2015, you know, that's a consensus. a statement essentially from those groups and they're representing three countries

and they don't, I'm sure, don't agree on everything and even in the document they note that different countries will ultimately probably want to have some of their own specific rules but they're certainly pretty clear that they all agree that the work is not able, you shouldn't be doing this kind of germline gene editing just yet. And actually I wanted to add that the US government,

the Congress actually has actually passed a piece it's a budget rider that was passed first in 2015, but has been passed since, that prohibits the FDA from looking at any application to do clinical work that would result in inheritable change. So that would cover this kind of study. And so, as Dr. Cannon said, you would have to go to the FDA if you wanted to do this kind of experiment in the United States, but Congress has actually prohibited the FDA from looking at those

or from entertaining. So you couldn't get permission right now. would actually be against the law. I have a quick tweet I want to get to before the break about a minute. Adam writes, as a type 1 diabetic, if gene editing had been around when I was conceived, I wouldn't be suffering today. How do you answer that? Well, that's not strictly correct, I would guess,

because type 1 diabetes was still not sure what triggers that in many cases. So it would be really hard to sort of make a change into an embryo to make you resistant to that. However, you know, there are lots of other potential new types of therapies that are being developed to treat type 1 diabetes that use gene therapies and cell therapies. So there's some positive things, I think, coming down the line that can treat people who have type 1 diabetes. But the idea that we could predict this at the embryo level and make changes to protect is not correct. All right. Sadly. Yeah.

We're going to talk a quick break and talk more about this when we come back with my guest, Josephine Johnston, bioethicist. and Director of Research at the Hastings Center in Garrison, New York. Paula Cannon, Professor of Molecular Microbiology and Immunology at USC in Los Angeles. Our number 844-724-8255. We'll take your calls and some more tweets. You know, I don't want to use the Christmas tree analogy, but the board is lit up. We'll be right back after this break. This is Science Friday.

I'm Ira Flato. We're talking this hour about using CRISPR gene editing to alter embryos. So my guests are Josephine, Johnston, and Paula Cannon, our number 844-724-8255. Let's go to the phones. Let's go to Denver. Alex in Denver. Hi, welcome. Hi, Ira.

Hi, there. Go ahead. Yeah, so my question is, regulatory issues aside, if we could imagine a future where this is assumed to be ethically okay, why is that future not here yet? What are the ethical issues around the timing of this that need to be addressed before we could reach that future state? there's a lot of excitement about it. Yeah, good question. Dr. Johnson, you want to tackle that?

Well, the big issues are safety and efficacy, does it work, and is it safe, and how safe is it? Because nothing's usually 100% safe. But the other big question, I think, is this question about whether or not it's appropriate to make permanent changes to future persons' genomes? And if it is appropriate, is it appropriate to make any kind of change whatsoever, or are there only certain kinds of things that ought to be changed? And the kinds of things that people might argue is that we should,

just make changes related to lethal conditions or very serious genetic diseases. Some people would like to see some disabilities, but not others, be subject to this kind of editing. Other people are really looking forward to being able to edit genes associated with tiny increases in IQ or height or athletic ability, controlling eye color, etc. So none of those, the scope of the appropriate targets, even if we could do those things, the scope how appropriate. read it is and how much how much leeway to give to prospective parents versus how much to control at a regulatory or legal

with legislation. Those are all questions that have not, just haven't been worked out. Dr. Cannon, any comment? Yeah, and I actually think that the gene that was chosen in this case, the CCR5 gene, is really a perfect example of how the choice of the gene

and the appropriateness of it is really in the eye of the beholder. Dr. He claims that he disrupted the CCR5 gene because this would give these little girls the ability to be resistant to HIV. And he seems to think that that's an appropriate thing to do. Whereas, you know, I think a lot of people would argue that there are much easier ways to prevent yourself getting infected with HIV. You know, we have safe sex. We have drugs people can take that really this was like a sledgehammer approach to do something. So I think, you know, he's maybe inadvertently created almost like a perfect textbook example of the complexities around discussing what would be appropriate uses of this technology.

And how did those discussions happen? Gosh. So, again, you know, the main people sort of discussing this right now, and I think up to this point, have largely been people in the community who are the gene editors. I'm not entirely convinced we're the right people to be having these discussions, but certainly we understand the technology behind it. Even the sort of international summit that's going on this week and the prior statements from the national academies tend to come from people who are experts in the technology. And you could argue that we're a slightly biased group,

maybe one way or the other. I think the public needs to have a greater say and what should go forward. And one of the challenges there is how to help the public to understand, you know, the reality and the potential, including, you know, things that are not realities for this technology. Dr. Johnston, you agree? Yeah, although I do note that both the summit and the National Academies here, those panels had non-scientists on them as well.

So people from sort of the bioethicists, actually, I wasn't on the panels, but bioethicists, and people from religious traditions or people who work in other sociology or patient advocate. So it's not just the science community. And in fact, one of the inventors of CRISPR Jennifer Dowdner, very early on, right after the initial papers were published, came out with a paper saying, like, we can't just have this conversation in the scientific community. This has got to be a more open conversation. I think having that conversation at a granular level is difficult. But here we are right now having this conversation on the radio.

So getting some people talking about it and reading about it, people talking with students. So the Hastings Center ran a workshop this summer for high school science teachers to equip them to actually teach the stuff in their classes and to encourage their students to reflect. So there's a lot of work to be done at multiple levels. Yeah, because I have a tweet from Kerry says, I think, CRISPR is incredible. Someone had to take the risk.

If both parents are well-informed and not being coerced, And I see no moral issue. I only have my own two incredible children, thanks to the, quote, miracle of science. So the one thing I wanted to say about that kind of, I really understand why people would like to leave these decisions with parents. And at the end of the day, I actually agree with that. But I want to note that we all know that there are many social pressures bearing down on people as they make decisions about this kind of thing. So if you started to see a pattern, for instance, of American parents choosing, genes associated with lighter skin color, you might think, oh, that's just parents making

their own free choices, or you could understand that that's a result of a persistent racism in the country. So there really are social issues and cultural context that shape the kinds of decisions people make, and it's important to also be addressing those in so far as they represent unjust situations. So I really value autonomy and individual decision-making, but I want us to not forget that there are injustices and inequalities that can put a lot of pressure on people to make choices they might not otherwise make.

Do you think that this news about this will begin a conversation like we're having and make one a lasting conversation? Do you think that's going to happen? You know, actually I think what's interesting is to my mind it's sort of shifted the conversation a little because up until this point I think there was possibly a naive view that we could draw a line, that there would be a very bright line between applications of gene editing that might be appropriate, treating embryos from parents who are carrying an inherited genetic mutation, for example, but that other applications, which are broadly considered personal preference or

enhancement, should not be crossed. And I think, if anything, I've been thinking this week that now that the gene is out of the bottle, so to speak, it's just completely ridiculous, I think, to talk about only having, you know, sort of therapeutic applications. If this goes forward, even with the sort of best of intentions to treat, you know, truly terrible genetic diseases, then this is going to sort of, you know, further develop the technology, make it safer, make it easier. And then, you know, I don't see how you can draw the line at all. All right, we're going to leave it there and come back to this very important topic.

Josephine Johnston is a bioethicist director of research. at the Hastings Center in Garrison, New York. Paula Cannon, professor of molecular microbiology and immunology at the Keck School of Medicine at the USC in Los Angeles. Thank you both for taking time to discuss this with us. Thanks for having me. Yeah, thank you. Think of something symmetrical in the natural world,

meaning you can reflect them in a mirror and they'll look the same. For example, the two wings of a butterfly, the two sides of a leaf, the two sides of your face. But surprise, surprise, many things you'll encounter in biology are built on a foundation of asymmetry, even down to the cellular level. Your tissues tilt and twist and take on shapes that no amount of reflection will make into mirror images. In fact, your heart is solidly on the left side of your chest, right? And even your lungs are two different sizes.

Where does this come from? Researchers writing in science are on the trail of one mechanism, a single protein that seems to twist cells in fruit flies, bodies until the entire animal is warped. Here to explain is Dr. Michael Ostap, a professor of physiology, University of Pennsylvania's Perlman School of Medicine in Philadelphia. Welcome to Science Friday. Thanks so much for having me. Jule down for us. What are the different ways organisms might be asymmetrical? Okay, so if you take our body and you look at us from the front, as you just said, we have this symmetry. You put a mirror down the side of us, the left looks like

the right. But as we go a little bit deeper, you will see there's an asymmetry. As you just said, the heart is on the left. The organs are scattered around. But what's really interesting is even though it's asymmetric, we're all the same, except for very rare instances we all have this same type of asymmetry. Interesting. And I understand there's this term chiral, another kind of asymmetry. How is that special? So the chiral is if you have a similar shape but an opposite orientation. And a really good example is if you consider your hands. So your hands are symmetric, as we just talked about, but you can't put your right hand in a left-handed glove.

So this is this chirality. So something in biology happened that allowed this chirality to occur. Let's talk about the fruit flies. Take us to the fruit flies. What is this protein doing to them? So it's actually setting up some of this chirality. So if I can take a second, I just want to tell you about this previous experiment that our collaborator, Stefan Nasseli, did, in order to address this question of corality. So in fruit flies, they're symmetric, just like we are, the left and left sides.

But if you look at their internal organs, you'll see. that some of them have a twist. For example, the reproductive organs and the intestine has a really well-defined directional twist. And so the Nasseli group wanted to ask, what is responsible? Can we identify a gene that's responsible for giving this specific handedness, this specific twist? So they used the fruit fly to start modifying genes to ask specifically which one, are important for making this twist. And they discovered a molecule called Myosin 1D,

so that if you knocked it out in the fruit fly, all of a sudden these organs would have the completely opposite twist. So this particular gene, the protein expressed by this gene, gave a specific corality. So to the fruit flies, do we have anything similar to that in us? We do. We do have myocins. So myison is my favorite protein.

So it's a really incredible, literally a nanoscale molecular motor. It's a protein that interacts with cytoskeletal filaments and is able to walk along these internal filaments inside your cell and transport membranes and other components. And we absolutely have this myosin. So are they twisting and turning our cells, the myosin in there? So it is. That's cool. So where my lab came in is we asked, so my research specialist, Serapian Proposopolis, asked, okay, this myison is a protein we know.

Can we actually learn something about this molecular motor that tells us why this corality could emanate from it? And so he did an assay where he looked at the gliding of these cytoskeletal filaments. He put the protein down on a cover slip, and he labeled the cytoskeletal filaments, and what he saw was that these filaments turned in circles. So this particular myocin gives corality to the cytoskeletal filaments, which is really quite amazing. So they're like little motors? They are exactly motors. They're little transporters.

They're nanometer-sized transporters that use chemical energy to do mechanical work. They're very similar to the proteins that make your muscle fibers contract. Wow. I'm Ira Flato. This is Science Friday from WNYC Studios. Talking with Michael Ostap, a professor of physiology at the Proven School of Medicine in Philadelphia. Why is asymmetry so mysterious if it's also so common, Dan? It's because the asymmetry occurs very early in development, and it's been very difficult to figure out in different cell types where the asymmetry comes from. And so because of that, this current paper addressed that point correctly.

So the question is, can this particular myocin, this Miocin 1D, can it make a tissue that's not normally chiral? Chiro. And so what this paper is all about is taking this protein and expressing it in the epidermis, just the outside skin layer of the trosophila larvae. And what happens is this non-chiral tissue all of a sudden twists. So this whole body of this fruit fly is now twisted. And in fact, if you take the protein and you extend the gene and you express it in another organ, for example, the trachea, the breathing tube of the trosophila,

If you just express this protein in the trachea, that as well will twist. Well, we need to call it the chubby checker protein, I think. Okay. So everybody can get with it. Could we harness this protein in some ways besides just making weird-looking fruit flies? So could we, well, could we harness it? So, well, what we can do is we could study it in a more complicated system, and people have been doing that.

So the gersophalus system is a bit different than a vertebrate system. So corality occurs in a slightly different way in a human or a mouse or a chicken. And there's another molecular motor called dynine, which I guess I'll say is my second favorite protein, that causes these hair-like projections from cells to twist and scatter growth factors around the inside of a development. developing organism. So it turns out, though, that this Myosin 1D may be important for the establishment of those cells that have those other types of dine-twisting mechanisms.

So where do you go from here? Okay, we've got your two favorite proteins down now. Where do you – what – where is the research head? Ah, so, okay, so we know the genes. We know the gene products. and we know some of the cells that they're in. Now, the really interesting question is, how are they actually working? So I'm a biophysicist, and I'm really interested in the specific molecules

and how they interact with their filaments and how they're controlled. So how does this molecular motor that does twisting affect cell morphology, so just the cell shape? How does this protein affect the cell shape that allows these larger order twists? to occur. So I'm just really interested in getting in there and dissecting the cell and asking when these myisons make force, what are they interacting with? And we already have some really nice clues that these motor proteins are binding to proteins that connect cells together. So these motor proteins may be biasing how these cells connect and causing overall, just the overall

large cell sheets to twist. Well, just like a sheet, you know, a sheet of molecules or a sheet of cells together, they just twist them around. That's right. So if you look at a sheet of normal epithelial cells, it kind of look like a bunch of hexagons that are packed together.

Really beautiful. When you overexpress the myosin-1-D, these hexagons all distort, like you pull from opposite corners and you form the shape. And so that deformation is allowing this overall epithelium to change in shape. Now I see why you find this interesting.

It is fascinating. Thank you, Michael, for taking time to be with us today. Oh, it's great being here. Thanks so much. You're welcome. Michael Ostop, Professor of Physiology at the Prolman School of Medicine in Philadelphia. We're going to take a break and talk about something else amazing. Balleen whales like the humpback feed on the tiniest of ocean prey with the help of fibers in their mouths.

No teeth needed, but they evolved from a, well, interesting. They sucked years ago. We'll talk about what happened. This is Science Friday. I'm Ira Flato. Humpback whales, blue whales, great whales, gray whales, they're all giants of the ocean, some of the largest animals ever to live on Earth.

And they've gotten that way while filtering the seas with their bristle-like baleen for the tiniest of prey. Balleen, big draping mats made from the same material as hair or fingernails. But how did Baleen evolve in the first place? We know from fossil skulls of whale ancestors, teeth came first, but did they lose their teeth before developing Berlin? Or was it a gradual phase-out? Paleontologists with the Smithsonian National Museum of Natural History described a new species in current biology this week that might have an answer. A 30 million-year-old skull that had neither teeth nor baleen and it ate by sucking up its prey.

That's what I said, sucking up its prey. Here with more is co-author on that new research. Carlos Pareto, a Ph.D. candidate in paleontology at George Mason University. He's a pre-doctoral fellow at the Smithsonian. And we wish you good luck, Carl's. Welcome to Science Friday. Hey, Ira, great to be here. How are you today? Fine. How are you?

Doing well, doing well. Good. Tell us about this suction feeding wheel. Like spaghetti, slurping stuff up? Yeah, not too different. This whale, Maya Belina, is about 33 million years old, and it doesn't have any teeth. It doesn't have any baleen either. It basically fed like a vacuum cleaner under the sea. And how can you tell them from just looking at the skull that the baleen, you know, was not there?

Yeah, so baleen, of course, does not fossilize the way bones do. We wish it did because I would tell us a whole lot more about how it originates. but baline, because it isn't made of bone, it's sort of rare in the fossil record, and you're always kind of looking for a little bit of evidence or a little bit of any kind of sign that baline may or may not have been there. In the case of Maya Belina,

one of the things that really tells us that baline is missing is that the roof of the mouth where the baline would normally attach is very, very thin, and so the bone there is not robust enough to actually support attachment for a structure so complicated like baline. So how do we know there weren't teeth there instead? Well, teeth are much easier.

In order to have teeth, you either need to find teeth or you need to find tooth sockets. And in the case of my ablina, we have a complete skull and a very complete lower jaw as well, neither of which have any tooth sockets or any teeth at all. So that one's a much easier one to figure out. Okay, so tell me why it's so important that this whale didn't have baline or teeth. Well, the reason it really is important is because, you know, We've known for a very long time that even though baleen whales today don't have any teeth, we've known that they came from toothed ancestors.

And that actually goes all the way back to the 18th century when we were first starting to do things like wailing, and people were finding in embryos of whales and fetuses of whales that they had teeth when they were in utero. And so we've known that they've had toothed ancestors for a long time. But understanding how you go from having teeth to suddenly not having teeth and having baleen instead is a really complicated story. And so what our study does for the first time, it really shows us that you have this extra step in the middle here where you don't have either structure at all, and instead, you're feeding with suction. Wow. So what is the advantage of the suction over either one? Well, suction is a very successful feeding mode for a lot of animals in the water, and that's not

just whales. There are lots of other marine mammals. If you think about a walrus, for example, they're very effective suction feeders. Other kinds of whales, such as beaked whales or beluga whales, even the gnar wall. These are very effective suction feeders. And so one of the things we think is that it's energetically more efficient because instead of having to chase down your prey quite as quickly, you can instead use a little bit of suction to help bring it towards you. So if you're going to evolve into a big giant whale,

does that mean you need the baleen to be able to suck in all those little tiny creatures, make you big and strong? Well, that's an excellent question. And the relationship between baleen and body size is something that has really been, We've been trying to figure this out for a very long time. And as best as we can tell, baline definitely is a good first step.

But one of the things that you also need in order to get really massive, like some of the biggest whales today, is you need a very high density of prey as well. So it's not just having the baleen, but you also need your prey to be very, very compact, very dense in one location so that when you are doing something like filter feeding, you're getting huge quantities of prey as well.

If you think about a blue whale, for example, you know, up to 150 tons, sometimes as much as 100 feet long. Even if you have Baylene, if you're going to get enough energy for an animal that large, when you do lunge, when you do take in a big gulp of seawater, you have to have massive quantities of prey in order to actually make that efficient. Yeah. Our number 8447248255, 844 SciTalk, you can also tweet us at Cyfry. If you've ever stood under the Big Whale at the American Museum of Natural History

and wondered how does it feed and all that's not. And how did it get all that, Baleen? That's what Carlos Pareto is. How did you get involved in this, Carl? That is an excellent question. You know, I think for most paleontologists, there's some love of whatever animal they study, right? So for most people, it's dinosaurs.

They're very much enamored with the fossils and with the dinosaurs for most people. I'm a little bit different. I didn't quite take that same approach. I do love whales, of course, but that isn't actually quite why I started getting into whale paleontology. I'm driven more by sort of the unusual or the bizarre when we think about evolution.

And so if you imagine a whale, you imagine a terrestrial animal that has teeth and not only has teeth, but it uses them. It's feeding on land and it's chewing. It's using its teeth very actively. And then you imagine what it must take to put that in the water and have it lose its legs and have it become an efficient swimmer and have it be able to hold its breath for hours at a time and have it be able to eventually filter feed. You know, whales to me are just an example of so many unusual and very extreme transformations that, to me, they're a perfect animal to study because they really teach us about evolution and how evolution actually works in mammals. That's a good point. I'm glad you brought that up because this is, excuse me, ocean mammals are something that I'm really fascinated by. Do we know what mammal was on land, as you pointed out, that evolved and went into the ocean?

What did it start out as? Sure. So the oldest ancestor to a whale that we know of right now is an animal called Pachycetus. It's from the Indo-Pakistan region. And when I try to describe to people what it's like, it's about the size of a large dog. It's very hyena-like, and it's probably in the way it ate, in the way it operated. But it's actually not related to dogs or carnivores in any way. It's actually related to our hooved mammals. It's actually most closely related to cattle or even hippos or deer, any kind of hooved animal like that. And so as unusual as it is, I always try to tell people, imagine you have like a dog-sized hippo kind of hanging out in the near-shore waters, and that would be sort of the precursor to what would eventually become the giant whales that we know today. Do we know what the catalyst for sending our dog-sized hippo is going into the water? Okay, why give up that life and say, hey, you know, I'm going to develop flippers and things.

and become an ocean mammal. Yeah, of course. So, you know, the Y is always the hardest part for paleontologists. It's always the part where we get a little speculative because we can never truly know. But one of the things that we know about this time period when whales first started going back to the water is that the Indo-Pakistan region at the time was a tropical archipelago.

There would have been high seas and there would have been a lot of water available at the time. And one of the things that we think is that there were resources available in the ocean at that time that other mammals were not exploiting. Mammals were not at that time in the water at all, and so it would have been sort of new resources that no one else could have tapped into.

And so if whales started hanging out in the near-shore environments there, they would have been readily able to sort of start taking in those resources that no one else could get. But we have so many different kinds of whales. Were there many different dog types of mammals that they all evolved from a single one or many different ones? Well, at some point there is one common ancestor for all modern whales today. And so yes, yes.

Wow. Let's go back to your discovery and you're talking about suction feeding whales and the baleen. How is a scientific community, your fellow researchers, taken to this idea? Is it a controversial one amongst your peers? It's a little bit controversial. I would say it took a little while for us to convince even ourselves. know, for a long time, the going assumption had been that any time you found a whale, especially a whale fossil, that it must be in either or, it must have teeth or it must have baline. That had been

the going assumption for a very long time. And so when we started working on this whale, we could pretty quickly tell that it didn't have teeth, because like I said, there's no teeth and there's no tooth sockets anywhere in the bone. But we really wanted to challenge ourselves to not just assume baline. We didn't want to assume baline from a lack of evidence. We wanted to look for evidence for Baleen. And so we spent a lot of time really coming up with all the different ways that we could test for it. One of the things that we did was do very high-resolution CT scanning on this fossil so that we could actually visualize what the inside of the bone looks like.

And that tells us a lot about whether it could have supported Baleen, and in this case it could not. And so at first, there was very much this, even amongst ourselves, we had to really think, like, could this really be possible? And the more work on it we did, the more we started to convince ourselves. And that led us to looking at these other whale groups, you know, looking at other groups of whales and asking ourselves, are there any other whales alive today that feed like this? And the answer is yes, overwhelmingly yes. Things like narwhals, things like belugas, things like beaked whales, even sperm whales. They are all examples of whales that either have no teeth at all or have teeth that they don't use as part of feeding.

And so once we kind of re-looked at our whale, we re-looked at Maya Bolina within that context, we realized this isn't so far-fetched. And not only is it not far-fetched, it actually makes a lot of sense because this sort of toothless suction is something that whales do repeatedly in their evolutionary history. It's actually a very effective method of feeding. And once we started compiling that argument, that's where, you know, most of our colleagues started to kind of come around and realize, okay, yeah, that actually makes a lot of sense. Are there any clues in living whales that can give us about how this might have happened? Clues in living whales about the transition from teeth to baline. I mean, that would say, yes, this did happen. So the biggest thing that you can look at in modern whales is you can look at the fetal development.

So we know that when whales are in utero and they're going through the gestation cycle, they actually start to develop teeth. So they go through three of the four key stages of tooth development. And then there's a point in the womb where the whale embryo sort of stops growing its teeth and instead starts developing baleen. And that, I think, is a really key place in the modern whales where we can really start to ask ourselves, just how does this happen? What are the genetics that control this? What are the molecular components that control this? The fossils are a really great single puzzle piece.

But when we put it all together, that's going to really tell us a lot more about what's going on here. Amira Flato, this is Science Friday from WNYC Studios, talking with Carlos Pareto about his study of Baleen Wales. It's got to be very hard then, right, to find Baleen in the fossil record because it doesn't, right, doesn't fossilize very much. Does that make your job very hard? In some ways it does, absolutely. So, you know, it's not that it never fossilizes. there are a few instances where, you know, we're fortunate enough to have Baleen fossilized, but one of the things that you really need in order for that to happen is you need very rapid burial.

So because Baleen does not physically attach to the bone itself, Baleen is anchored to the bone via the gums, via the gingiva. And so what happens is after a whale dies, very quickly after death, the soft tissue begins being picked apart by scavengers, and the baleen itself tends to sort of come off in a sheet. they comes, it separates itself from the bone. It's almost like pulling up carpet. And so unless you have a very, very rapid burial,

the baleen will actually come off very quickly. It's very difficult, very rare for you to find baleen in the fossil record for that reason. But in a few cases, we are fortunate, and we do find some. You're always hoping when you go out in the field. Absolutely. Speaking of going out in the field,

let's go out on the phones to Denver. Laurie and Denver, hi, Lori. Hello. I understand that flamingos are also baleen feeders, and I was wondering if there's any correlated development with their baleen and the whales baleen. Hey, Lori, that's an excellent question. Flamingos are filter feeders, but they don't quite use baleen. They use a similar but unrelated structure.

It does the same thing. It almost works like a hair comb or like on the bristles on a hairbrush. It does a very similar thing. It also strains food from the water like a sieve or like a colander, but it is unrelated to Baleen. It's actually a separate structure. Good thinking, though, Lori. I like thinking about that kind of stuff.

Thanks for calling. Is that kind of feeding the filter with Baleen an efficient way to gather food? I mean, is popular? Is that why it's so popular? As far as we can tell it, it absolutely is. And one of the reasons for it goes back to what we were talking about with the density of your prey. If you think about both feeding modes like feeding with your teeth or even a suction feeder, those are both feeding modes that target individual prey items, right?

So if I'm going to, if I'm a bottle-nosed dolphin, for example, and I want to catch a fish, I'm catching a single fish at a time and swallowing it, even if I'm a suction feeder, I'm probably targeting one fish or one squate at a time. One of the things that filter feeding lets you do is it lets you feed in bulk. It lets you kind of just go through the buffet line and have as much as you want to. as you possibly can. Well, if you're gulping in all this water as a filter feeder, and this is salt water, and you're a mammal,

and you can't really absorb all that salt water, can you? What happens to all that water? That's an excellent question, and that's where the baleen comes into play, right? So the baleen allows you to separate the water from the food sources, in this case, krill or plankton, or even in some cases, fish. But it lets you kind of tease those two things out. It's only like when you're, when you strain pasta, right? after you're done boiling your pasta and you put it through the strainer.

That's what the bailine is doing there. It's removing the water from the food source. There was a skull that you're talking about was sitting in a museum since the 1970s. Are there other skulls waiting to be discovered? Other things are museums the answer here? Their collections. The short answer is yes. For a long time, museums have been collecting a lot of fossils, and it takes a lot of people power

to actually go through that and take a fossil from the day you dig it up to the day that you're able to study it, it takes a lot of people power, mechanical processes and chemical processes that have to continue to separate the bone from the rock in many cases, or like in our study where we did the CT scanning, because in some cases the bone was too fragile and it couldn't be separated mechanically. And so that's where the CT scanning lets us digitally separate the two. And so once you're able to do those things, you're able to study the fossil, but there's a big bottleneck there. And so yes, absolutely museums are a treasure trove of new

information, and there's always another specimen to start getting into. All right, museums be aware. Carlos Parada is on the hunt to your museum. He's a PhD candidate in paleontology at George Mason University and pre-doctoral fellow at the Smithsonian National Museum of Natural History. Thank you

and good luck on your quest to be at PhD. Thank you so much. One last thing before we go, we need help from you, our listeners, for a new project. We've teamed up with the group flu near you to track your flu symptoms all season long, using your crowdsourced data epidemiologists, contract the spread of the flu this winter, and get that information back to you,

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