Science Friday - 2020 In Review, Charismatic Tubeworms, Dog Evolution. Dec 25, 2020, Part 1

Episode Date: December 25, 2020

2020: The Year In Science, With Wendy Zukerman It’s the end of the year, and time to reflect. While there’s no doubt the coronavirus and efforts to combat it led the science pages this year, there was more to this year than masks and hand sanitizer.  Wendy Zukerman, host and executive producer of the Gimlet podcast Science Vs, joins Ira to talk about this very strange year, and recap some of the best science—from the rise of COVID-19, to climate change and wildfires, to the discovery of fluorescent platypuses. Plus, check out some of Science Friday’s favorite stories from the year. These Worms Are Superheroes Of The Sea If winter has felt gray and colorless for you lately, cheer up and join us for a special, festive edition of the Charismatic Creature Corner. This month, we’re looking not at one creature, but a whole class of them: Meet the polychaetes, also known as bristle worms. (“Polychaete” translates to “many bristles.”) Yes, they may seem short on charm—they’re worms, after all. Many, like the bloodworm, the bobbit worm, and the bearded fireworm, pack either razor-sharp jaws, or a painful venom.  But they’re also both gorgeous and mighty. Polychaetes come in iridescent colors, with feathery fronds or intricate patterns. Just in time for the holidays, consider the cone-shaped branches of the Christmas Tree worm, which makes its home on coral reefs. Others, like tube worms, produce energy for whole ecosystems from chemicals in the deep ocean’s hydrothermal vents or even the bones of dead whales. Still others, like alciopids, have remarkably human-like eyes. Gossamer worms can shoot yellow bioluminescence out of their arm-like bristles. And thousands more species provide lessons in marine evolution and invertebrate biology for the eager explorer.  This week’s Charismatic Creature Correspondent, producer Christie Taylor, asks Ira to consider polychaetes—all 10,000 known species—for entry to the Charismatic Creature Corner Hall of Fame. Helping make the case is Karen Osborn, curator of marine invertebrates for the Smithsonian National Museum of Natural History, and a seasoned ocean explorer and discoverer of new species. How Did Dogs Evolve To Be Domesticated? Human DNA ancestry kits have become very popular in the last few years—and now, the trend has arrived for canines. A group of scientists recently mapped out the genomes of twenty-seven ancient dog genomes, looking back as far as 11,000 years ago to trace the evolution of the domesticated dog. Their findings were published in the journal Science.  Producer Alexa Lim talks to two of the study’s authors, evolutionary biologists Anders Bergstrom and Greger Larson, about what this tells us about the origins of the domesticated dog, and how they evolved to be pets. 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. Merry Christmas, to those of you celebrating. Later in the hour, a strangely charismatic creature, the tubeworm. A look at the evolution of dogs also. But first, it's the end of the year and, of course, a time to reflect on some of the stories from the year and some of the stories that didn't get as much attention as they might have in this kind of weird year, of course, right? And here to help navigate through the year in review is Wendy Zuckerman. She's host an executive producer of the podcast, Science Versus, from Gimlet, a Spotify studio. Welcome back to Science Friday. Thanks for having me.

You know, it's been kind of a tough year for science stories to leak through all the main, right? The main science story has to be COVID. It has to be COVID. I mean, it's been a hard year for other science stories, but it's been an exciting year for science and getting people to appreciate and understand science and care about science. on the other hand, it's been a very difficult year to be reporting science. Yeah, let's begin by talking about how the coronavirus story developed over the year. When we first reported on it, it was just an unusual outbreak in part of China, right?

Yeah, I mean, it's interesting. The way I first heard about it was actually from a doctor in Hong Kong. In January, I get this email. And it was just really very sparse. It just said there's been a respiratory virus spot. in Wuhan, China, we're keeping an eye on it. And I really didn't think much of it. The bushfires were on. I had other things to be thinking about. And it really wasn't until several weeks later that we started to see how bad the outbreak was in Wuhan. And then it really took several

months later, I want to say March before we knew how bad it was in the United States. And we really didn't know where it came from in those early days. And we really didn't know where it came from in those early days, did we? I mean, there was a lot of talk of the wet market. You'll remember those headlines, the wet market, the wet market. Even though actually from very early on, there was a Lancet paper that had noted that there were cases before the outbreak at the wet market. So even, I think, in January in China, we knew the outbreak didn't start at that, you know,

now infamous wet market, but we knew that there were obviously a lot of cases and there was a big spreading event that happened there. But in terms of the very first human to get infected, that remains a mystery. Your podcast Science Versus won the AAAS Kavli Award for your coronavirus coverage. First, let me say congratulations. Thank you. What have been some of the challenges in covering this story? Oh my goodness. I mean, the misinformation and the myths about this coronavirus have come up like a 10-headed hydra. I mean, we'll chop one down, 10 more, show their face. It's been kind of unbelievable.

And then from our perspective, you know, on our show, we try and spend as much time researching as possible, so we're not just pumping out stories. We really had to pick and choose what were the myths that really needed covering and what were the things that were just going to die down on their own. focus our attention on what are the big myths that are actually going to be helping people right now? And what can we actually tell them? Because another big issue was at the beginning of this pandemic, even though the science was coming out at this amazing rate.

I mean, it has been phenomenal to see from a public perspective who perhaps aren't used to the slow, graceful grind of science, it wasn't fast enough. And so they needed answers and they needed them yesterday. and lab work takes time. And so being able to explain that and to sort of say, look, in the meantime, while we don't know everything based on the information we have at the moment, this is what we think, both be explaining the scientific process

and helping people live their lives. Yeah, being in the intermediary on this to the public is, I noticed from our coverage really is difficult. Let's move on a little bit because we know, as I mentioned earlier, there were a lot of other stories that were very interesting and very relevant and very important. For example, the fires in the American West. And when we spoke around this time last year, you were heading back to Australia where the fire

situation was awful there also. Yeah. And it just got worse after we spoke. What did you do? It was truly, truly awful. I mean, I went back to my home city, Melbourne. And the smoke on some days was just awful, you know, worse than I'd ever remembered as a child. And it was devastating. I mean, the sort of good news is, you know, now we've switched. So what was happening in Australia, it wasn't just climate change. Climate change is obviously a big part of this picture, but there were other climate systems at play that made that fire season really, really bad.

So we were in this sort of more dangerous cycle of El Nino. So that meant there was sort of drier conditions across Australia, less rainfall, it doesn't take a genius to see that that's going to bring sort of climate conditions more likely to start a fire. Now we are in a Latinña cycle, which is good news. So we should expect to see more rainfall. And I mean, already, while we have seen some fires throughout Australia, we are not in the position we were in last year.

And, you know, one of the realizations about climate change is it's not just the fires, it's not just the hurricanes, but it is the heat. Tremendous heat, and no country should know it better than Australia, which if I remember correctly, you had such high heat once summer. They had to change the map to put another color in it. That's right. We got purple in my lifetime. Red used to be at the top.

And then all of a sudden there was purple in there. I mean, it's just... So this must be the new normal now, right? If you've changed the map. It truly is the new normal, because even in a... in a fire season where we see this, and it kind of La Nina, which should make it nicer. We're already seeing quotes from the fireies over in Australia saying, like, we don't know what to expect. So, I mean, definitely the underlay of climate change here has made things quite scary.

And it's changed summer for Australians. I mean, now it's a discussion. You know, when you're planning your summer trips, it's like, where are you going to be? What might the bushfires be doing? And we're seeing that out in the west here and the southwest of the, in the state, we're seeing these temperatures that go up to like in Australia, 110, 120, and realizing that this is dangerous stuff now. And it's, and it is, what you said as the new normal. I mean, that was the realization when I was in Australia, it really hit me that after being a science journalist for, you know, more than a decade now and reading these graphs of what to expect from climate change, I was, I was just thinking, oh, it's here. it's here all those I mean we've known it we've known it intellectually for so long but when you live in it when you look outside your window and there is smoke when you're not supposed to leave the house

and this was not how it was before it really really hit me that I was like oh all those predictions all those graphs where I just saw the lines going up and up and up it's here it's here and it's very sad one of the stories that came out of this year's election and I really was surprised by this there was a widespread shift of drug policy in the U.S. This was amazing. In every state where it was on the ballot, the drug laws were changed and liberalized, liberalizing where marijuana could be used, even heroin and mushrooms in some of the states. Amazing.

Did you see this coming? I did not. You know, and the interesting part is that it crossed party lines. It didn't matter which state it was it, if it was red, if it was a blue state. they all voted to liberalize the laws there. It's very, very interesting the direction we're going in. I mean, I guess people are just seeing that this way that we've been tackling drugs, the war on drugs, the way we're doing it isn't working.

Well, and to also see sort of experimental drugs like psychedelic mushrooms to be okay, I think in Oregon it was past, you could use that? That's right, that's right. And there was a really sort of a small but exciting study that came out this year. They got a little bit of attention that we reported on on the show about using psychedelics for depression to help with depression. And they're not using magic mushrooms. They're not using shrooms, but they use the active ingredient in it, which is called psilocybin. And as I said, it is a small study that got this attention to just 24 people. But we spoke to the head of that trial, and he was just so excited by the results he was seeing.

You know, it's not a magic bullet, but in his trial, more than half of the people. 13 said that their depression, which in some cases was sort of depression that had lasted decades and they'd tried other things, other medication therapies, things like that. None of that worked. But in this case, 13 people said that after taking these very hefty doses of psilocybin, a month later, they said their depression was gone. And he said when you compare that to the effectiveness of some of the treatments that are currently on the market, this is just out of this world. So he was really excited about where this might go. And the fact that Oregon legalized psilocybin therapy. You can't go to CVS and grab your shrooms from the store,

but in the future, you possibly will be able to go to a licensed therapist and try this. It is really exciting because we're not just closing the door on these substances that have been a taboo. We're kind of opening our minds, so to speak. I don't want to end without talking about one of the stories that maybe didn't get the attention. It deserves this year, Muggan, the chaos. you picked out a story about glowing animals. Please tell us more about that. This story came out around the time of the election, and I just thought it was so beautiful.

So scientists have discovered that when you flash UV lights, a black light on a platypus, it glows blue. And just the most beautiful blue that you want to imagine, kind of like a starry night just at dusk. And this is something that kind of shocked the reason. researchers because we know that this process is called biofluorescence and we see it in animal life. We see it in coral and fish. But in mammals, it's super, super rare.

And so to see it in a platypus just sort of opened these researchers' eyes to think, wait a sec, if these guys are glowing blue under UV light, who else might be? And since that study has come out, it seems like it's become quite a fun thing for researchers to do, just grab their UV lights, go in at night and just shine lights on their samples, whether they're in a museum or a zoo. And so we've also discovered the Tasmanian devil also glows blue, just a little bit around its snout and its eyes and its inner ear. Wombats, bilbies.

And I am, I don't know why, I have some suspicions why everyone's running on the Australian animal front. But I reckon if you start putting some UV light on your mammals too, you're going to find some exciting findings. Wow, wow. So you think this could be the hot news story of 2021? I think so. Biofluorescence. Bring it on, right?

You know, 2020's been the year of the coronavirus. 2021, vaccines and biofluorescence. I want to thank you very much for taking time to go down memory lane this year with us. Thank you so much. Wendy Zuckerman is the host and executive producer of the podcast Science Versus. We're going to take a break and let me come back. the charismatic creature corner has some new contenders, tubeworms and bristleworms. You'll see, you'll see, stay with us.

Doesn't sound appealing, but you'll find out after the break. Hey there, folks. It goes without saying this has been a challenging year, no. And if there's one thing we know for sure, it's that the need for fact-based journalism and the need for science are stronger than ever. At a time when science is continually called into question, science for, Friday remains committed to filtering out the noise and discussing the evidence supporting the science that you need to make informed decisions. You know that demand for Science Friday this year

was higher than ever, but you may not know that your donations are what's keeping us running. And right now, Science Friday has a dollar-for-dollar donation match, which means that any donations will be doubled. So, if you have a few dollars to spare and agree that this world could use more science, please support Science Friday with a donation. Any amount makes a difference. Go to ScienceFriday.com slash give. That's science friday.com slash give. Thank you and stay safe. I'm Ira Plato and this is Science Friday. It's time for another charismatic creature corner. Joining me is this week's charismatic creature correspondent producer Christy Taylor. Hey there, Christy.

Hey, Ira. All right. I know this is your first time on the charismatic creature beat, but remind our listeners of the concept, if you will. Yep, what we do here is pretty simple. I bring you a creature. I bring in a scientist for backup. And we together try to convince you that this particular creature is worthy of entering

the hallowed charismatic creature hall of fame, which means it gets to sit at the same imaginary charismatic table as some of the more popular creatures out there, like your red pandas, your sugar gliders, your blue whales, et cetera. All right, I got you. Go ahead. Yeah, and as you probably remember, we like to challenge ourselves here at SciFry.

We have tried to convince you of the charisma of everything from slime molds to vampire bats. And somehow I have been sweet-talked into liking both of those creatures. Okay. So what is today's offering? Well, Ira, I want you to think of it as a belated Hanukkah present,

or perhaps it's a Christmas present that I am giving myself. But either way, we're going to debate marine polychaetes, which are also known as bristleworms. What does that evoke for you? Well, I got to tell you that as a saltwater aquarist, I know what they are. And I have seen people keeping them in tanks. They're like crawly things sort of covered in bristles. I have the feeling that you may have to do some real fast talking to convince me of their charisma.

All right. That's fair. I will say, after looking at dozens and dozens of photos of these things, I think they're enthralling. And to convince you of their charisma, I am calling in a scientist for backup, Dr. Karen Osborne and Marine Scientist at the Smithsonian's National Museum of Natural History.

Welcome to Science Friday, Karen. Thanks for having me. Before I start to make my case about cuteness, I do have to get the bad stuff up front. We have to acknowledge that we have some really noxious stuff going on. I mean, some of the polychaetes that we're talking about are blood worms, fireworms, bobbit worms. Tell us about that, Karen.

Yeah, so there are some pretty nasty characters. out there in the polychaet group. The blood worms have four big hook-like jaws in their entire mouthyverts. And as the mouthyverts, those jaws come out and latch on to something. A lot of the polychaetes or the bristle worms are predators, right? They need some way to catch their prey, and that often equates to big jaws. The bobbot worm is a really cool worm that lives in coral reefs, and it has these huge jaws that are about twice as wide is its body and it sits there and has them spread open like a bear trap or something. And if a fish or something goes by, they snap clothes and catch it. Wow. So there's some pretty tough characters out there. Okay, one minute. Time out. For those of us who may not ever have heard of these creatures,

can you just tell us more about what makes a polychaete, a polychaid, do they have other names? Polyketes are a group of marine worms. They're segmented worms. They're related to earthworms and leeches. but the marine worms are co-polikeets or bristle worms. And the reason they're called that is because they have many bristles all the way down the side of their body. If you rub your fingers down the side of an earthworm, you'll feel that they have some little, really stubby little bristles, just a few of them on the side of their body. But marine worms, many of them, have lots and lots of these bristles, and oftentimes they're really long and you can see them. They're even really beautiful the way they reflect the light. But their name, polyquite, it means many bristles.

Now you've learned a new term. Thank you. I feel much better about that. And Karen, I know that there are many, many, many different kinds of polychaetes. So I feel like our best strategy for winning IRA over is to go through a few examples of species that are especially charismatic. And there's one I actually know IRA that you already like, which is deep sea, two worms. Two worms. Whoa.

Now you got my attention. I love two worms. One point for you guys now. Well, these are some of the long. largest and most charismatic worms in the polychaet group. And the tube worms that we find at hydrothermal vents can be as big around as your forearm. They have these big red, velvety-looking plumes that stick out of a tube. And they have millions of bacteria that live inside their body and help them make energy from the chemicals that are seeping up out of the ocean or bubbling up through the

hydrothermal vents. But there's a bunch of different kinds of tube worms in the polykeet group. and they are fantastic, and they live in these really extreme habitats, and they're really important parts of their communities, because all the other animals that live around these hydrothermal vents hide in between their tubes or live on the side of their tubes or try to eat the worms. So they're really cornerstone members of those communities and really important. You know, you really know how to get to my soft spot because you hit it when you said that they had a giant microbiome living inside of them. Absolutely. They are the kings of that. So almost their entire body is made up of these chemosynthetic

bacteria. They provide the sulfur that they pull out of water and they also provide the oxygen that they pull out of the water. And all those bacteria in their special organ that fills most of their body make energy for them. Not to mention that they're really beautiful with those big red plumes and the way they come in and out of their tubes. On the other hand, though, don't some of them still kind of, I know this term isn't very scientific. Do they just gross you out? Of course. Of course, they're worms after all, right? Absolutely. I mean, I spend most of my time trying to convince people like you that polychaet worms are absolutely beautiful, amazing creatures. And if you take a close look at them, they come in all different colors, they come in all

different sizes, the way that they move, then you kind of start to see the beauty in them. And that's really easy to do with some of the worms. Some of the worms are just absolutely gorgeous. One of my favorite ones are the gossamer worms or tamopterus. Think of like a palm fron or a fern frond that's completely transparent, a little bit shimmery blue maybe, and just weaves its way through the water and does it in an incredibly graceful way. And as a bonus, they can also shoot yellow bioluminescent light out the tips of their arms. Wait, wait a minute. Wait. Wait a minute. Say that again? They can shoot yellow biluminescent light out the tips of their arms that they use to swim.

Wow. Wow. That's one of those features you'd like to have yourself, right? I also know if there's also a Christmas tree worm, right? Seasonal now. Exactly. Christmas tree worms are one of the most beautiful worms, actually. One of the ones that hooked me when I was just a college student and I was diving on a reef and looking at these beautiful little multi-colored Christmas tree shapes that would stick out of the coral, and if you waved your hand over the top of them, they would instantly disappear. And then they'd come back out again in a few minutes.

Those are subelid polychaet worms. Absolutely beautiful little animals. Also tube worms, right? They have a tube that goes down into the coral that they retreat into when they feel like they're in danger. They're also really cool because they have eyes on the tips of each of those branches that you see. Can you imagine your Christmas tree with eyes on the tip? of all the branches. That's the only way I want to decorate my Christmas tree now. Okay, so you're sort of describing great superheroes. They have all this wonderful stuff going

for them, especially the light shooting. But what other special abilities do they have? Can they really be super? I mean, other than capturing prey in amazing ways, oftentimes prey bigger and stronger than themselves, there's some scale worms that live symbiotically on things like sea stars or corals. And they live. on the animal and they run around and clean it, they tend to be like a chameleon and match their whatever animal is that they're living on. There's alciopids, which are another one of the worms like the gossamer worms that lives up in the water column, not at the surface, not at the deep sea floor, but all that water in between. But one of the groups of worms that lives, there are

alciopids, and they, this is another eye story. Their bodies can be up to a meter long, so like three, four feet long, but only about as big around as a pencil. But on the front end of that pencil, they have eyes that are as big as the eraser on a pencil. And they're actually lensed eyes. They can see about as well as we can, which is just not really what you want to think about when you think about a worm, right? I'm thinking, yeah. So, Karen, I feel like you're undermining your case now suddenly. I mean, as a person who works on how vision has evolved, it's really, really interesting to look at all the different ways that all these different types of polychaetes have figured out how to survive in their habitat and to get the things that they need and to keep themselves safe, right? And so just

the thought of thinking of them, them looking at you is a little bit weird. But if you actually look at the animals themselves, they're so beautiful. And those big eyes with their crystalline lenses at the ends are just really nice. I think I'll leave you two together to look at each other. I'm still a little creeped out by a worm that can look at me as well as I can look at it. But going back to how they're adapted for so many habitats, isn't it true that we can find polychaetes basically anywhere in the ocean, including like ice flows? Yep. Anywhere in the ocean, we find polyketes all the way down to the deepest places that we've sampled. We find them in the ice in Antarctica.

We find them in methane ice as well, which is pretty awful stuff to live in. Pretty much every habitat, even up in freshwater, we find polyquite worms. Well, and here's one I find really fascinating. There's this kind called zombie worms, which Halloween wasn't too long ago, and they literally help us recycle dead whales. Tell us about that. They do. The zombie worms are fantastic. And I was actually involved in the discovery of them, which was really fun and exciting at the time. And they brought me this worm and they said, we don't really know what this is. And I looked at it and it looked like a worm on top. But on the bottom half, it had this lumpy body that had roots growing out of it in different directions. And I was like, well, it looks like a worm on top, but I don't know what's going on on the bottom there. What they are is they're polychaute worms. They make gelatinous tubes. And basically, there's larvae floating around out in the ocean. And if there is a whale that dies and sinks to the bottom, and one of these larvae hits that whale, it turns into a female,

and it settles on the bone, and it starts to grow roots down into that bone. And again, they have a really super cool, helpful microbiome that helps them digest the bone and turn the sulfur in those bones into energy. And so they have that big globular part of the body and all the roots. is the organ that all the bacteria are in, and they just grow continuously through the bone and digest it. And the worm has a pretty red plume that sticks up into the water and gets oxygen for those bacteria and for itself.

It's called a zombie worm. Did you name it? I did not. I did not name that one. Okay, okay, okay. We've definitely got some neat traits here, but can polyquites get beyond the G-Wiz factor? There certainly is the G-WIS factor. certainly is the G-Wiz factor.

And what I mean by that, can we learn anything from them? Oh, absolutely. So the zombie worms are a nice example of something that we didn't understand how these things happened before the zombie worms were discovered, right? So, you know, in the past, there's been lots of whales.

What happens to their carcasses when they get the ground? Pretty quickly, scavengers come in, right? And they get all the flesh and all the blubber and all of that off. But then the bones could potentially just sit there. But what happens is these zombie worms, they grow through the bones and they digest them slowly. And as they make them more brittle and more wholly, other animals can come in and break pieces off and then can access the nutrients there.

There's an entire succession that happens on a whale as it breaks down in the ocean over a couple of years and provides this really huge source of nutrients for things that live in the deep ocean. And so as we've been learning more things about worms and other animals out there in the ocean, we better understand. how carbon flows in the ocean and how important the diversity of animals is that are out there. We also can learn lots of cool things like how they move. So one project that I'm working on is looking at actually gossamer worms, and they swim really fast and they're really maneuverable. But what we know about how animals that have long bodies with lots of segments, what we know about how they swim, the gossamer worms should not be very fast.

They shouldn't be maneuverable and they shouldn't be able to swim for long periods of time. But we watch these things with the submersibles and the ROVs and we see them outrun us and outmaneuver us. And that's really embarrassing, right? When you've got like a $2 million machine and this little worm just outran you and you can't catch it. It makes you wonder, right, how they do it. And so we've started collecting them and videoing them with high speed cameras and looking at the mechanics of how they actually move and how. how they're able to be so maneuverable and move themselves through the water. And there's lots of really interesting things that we can then use for things like building a robot

to, say, swim up one of your veins to look at, you know, something that's obstructing there. Once you pick those animals up and you bring them back into the lab and you look at them under the microscope and you see what fantastic structures they have to solve their challenges in life, it's really cool. Like the bristles on bristleworms, they come in, I don't know, thousands of different shapes. There's 10,000 different types of polychaetes that have been described so far and probably about that many that haven't been described yet. And there's at least, I don't know, a guesstimate would be something like 500 to 1,000 different kinds of bristles on those different worms. And they're all to do different things. Some of them are to be able to crawl around in their tubes.

Some of them are to be able to cut holes in their tubes so they can make branches on them. Some of them are to be able to catch things. Some of them are to be able to dig into the type of mud that they're crawling around on. Amazing, yeah. So they're really all these cool mechanical things going on with these animals. I'm Ira Flato, and this is Science Friday. If you're just joining us, we're debating marine bristleworms or polykeets with Dr. Karen Osborne and this week's charismatic creature correspondent, producer Christy Taylor.

Karen, Ira, let me see if I can summarize the case for charisma with these polykeets. We have things like 10,000 species. They can shoot yellow bioluminescence. Some of them have human-like eyes. They have cool microbiomes. Ira, you love these. They also do things like help keep their friends clean. And they can live anywhere.

They're vital to marine ecologies. They live in the bones of whales. I mean, Karen, is there anything else we could possibly be missing from this list of amazing traits? Well, I don't know. How much time do you guys have? You've already convinced I have to just admit

going into this knowing the bristle worms I wasn't too crazy about it but Christy you rattled off all those great things especially the light shooting out from the arms and the microbiome Everyone loves a laser show

Yeah these are like the superheroes Of the ocean to me You know they can do all these kinds of things And the environment that they live that How far down in the ocean do they live some of these? As deep as we've ever gone on. So down at the bottom of the Mariana's Trench, we can find them too. These are the superheroes, I think, of the ocean. So, okay, you've done it again. You have

turned around. They must be included. Maybe a special spot in the Hall of Fame here. Oh. Wow. Okay. So Karen, does this bring you joy? It does bring me joy. I mean, it's a little bit of a cheat, right? Because there's 10,000 species, right? There's a lot of room there to describe a lot of cool, different things. And we could keep talking about them for a long time. But, but yeah, there are some really Okay, name all 10,000. Go ahead. I've got time. Can I just make up a bunch of weird-sounding words? All right. Well, thank you so much, Karen. Dr. Karen Osborne is curator of marine invertebrates of the Smithsonian's National Museum of Natural History in Washington, D.C.

And a polyquite champion. Thank you so much for joining us, Karen. Absolutely. It was really fun. And Karen, let me add to that. Thank you so much for helping me see the charisma of polychaets. And thank you, Christy. Christy Taylor, a Science Friday producer, and this week's charismatic creature correspondent. Thank you, Ira. If you'd like to see some of these polychaetes we've been talking about, by the way, you can go to our website, sciencefriety.com slash worms, just in case you need a bit more proof

that they are truly beautiful. We're going to take a break, and when we come back, dogs and humans have a long history of friendship. You know that, but how did that friendship first begin? the evolution and domestication of your friendly doggies. Coming up after the break, stay with us. This is Science Friday. I'm Ira Flato. DNA ancestry kits have become very popular in the last few years.

Even for one of the most beloved members of the household, your doggy. We've talked on the show about what these tests can tell you about your pooch's genetic history. And now a group of scientists went way back. They've mapped out the genome of the genome of dogs going as far back as 11,000 years to map the evolution of our furry friends. Producer Alexa Lim has more.

When you look at your Labradoodle, you might think to yourself, where did you come from? The family pet napping on the end of the couch can seem very different from their wild, wolfy counterpart. A group of researchers wanted to map out this relationship. They sequenced 27 genomes of ancient dogs to make a family tree of domesticated dogs and their prehistoric lineages. So what can this tell us about the evolution of the dog and our own human association with these pets? Their findings were published in the journal Science. My next guest are here to talk about that. They're both authors on that study. Anders Bergstrom is a postdoc researcher in the ancient genomics lab at the Francis Crick Institute in London, England. And Gregor Larson

is the director of the paleo genomics and bio-archology research network and a professor of Archaeology at the University of Oxford in Oxford, England. Welcome to Science Friday. Thanks very much. It's nice to be here. Thank you. It's good to be here. Anders, you study ancient genomes to understand human populations. So why I look at dog genomes? Why is that interesting to you? Well, I mean, I'm broadly interested in biological evolution and diversity. So in my past research, I have mainly studied humans and trying to understand human history by looking at genomes and genetic variation. And of course, domesticated animals have a particularly close link to humans. And so understanding their history also allows us to understand more about our own history.

Then, of course, dogs and other animals, they are interesting in their own right as well. You know, if we think about dogs starting out with this wild carnivore and transforming it into all the diverse dogs that we see today, that's an interesting instance of biological evolution in itself. When do we think that dogs split off from their wolf ancestors then? Well, I'm sure Anders would agree with me on this is that the short answer is that we're not entirely certain. The longer answer is that we have some pretty good bounds that we're establishing. So we know it was unlikely to be any earlier than, say, 40,000 years ago or any more recent than 10 to 15,000 years ago.

So somewhere within that gap is when this process, and we're not even sure how long the process took, but we do know that it was an interaction between wolves and humans that led to this kind of emergent product, which is the domestic dog. And that's kind of what your study is trying to pin down and get to. So, Anders, let's talk about this study. The entire dog genome has been sequenced, and you sequenced 27 genomes of ancient dogs. Can you talk about that, what you found? So we have dogs in the study from a number of places, from Europe, from the Near East, from

Siberia, and we can look at these early dogs and how they relate to each other. and try to reach an understanding of how they diversified and spread across the world. So what we found was that our oldest dog is 11,000 years ago. It's from northeastern Europe, in Europe, in the Near East and Siberia. They had already diversified at this point and likely spread across much of at least the northern hemisphere, including North America, such that we're looking at a quite early process. Of course, as Gregor mentioned, diversification probably was even earlier than this. It's interesting to compare this to other animals where they were mostly domesticated in the last 10,000 years after the advent of agriculture.

But with dogs, we have a situation where already before any other animal had been domesticated, we had multiple different types of dogs or genetic lineages that were spreading across the world. Much of our study is about kind of tracking those lineages over time, see how they mix and move and combine in complex ways. but it's worth noting that all of these early lineages, and we detect at least five, there might very well have been more, but all of these five early lineages are in one way or another still represented in present-day dogs. What was happening during human evolution at this time? Do the timelines kind of overlap?

One thing that is still kind of a mystery is how after dogs were domesticated, how were they able to spread so widely across the world? because at this kind of time period, what we call the late Pleistocene, we aren't really aware of any human migrations that are kind of large scale enough to spread dogs to all these places. But somehow they do, and they very quickly spread to a range of prehistoric human societies, perhaps because they were useful to a broad range of humans, but we still don't really know how this happened.

Do you have any theories of how these dogs were getting? getting around then? I guess you could imagine that there is some degree of contacts between human groups, even though we don't see it in their genomes. So perhaps they're trading and exchanging cultural ideas and items and perhaps even animals, in which case dogs could spread even though we don't see humans affecting each other at the level of DNA at least. Yeah, Gregor, what are your thoughts on that?

How were they maybe moving around then? are evolving in Africa and we kind of leave Africa at like 60,000, or at least the first time our species expands beyond that. Humans get everywhere in Eurasia and even down to Australia without dogs, but it looks as though people don't get into the Americas or into the Pacific without them. So there are big broad continental scales where people and dogs seem to be moving in conjunction and other ranges like in Australia where it's not easy to get there at 60,000 years ago, but lo and behold, there are people, and that's well before dogs are to do. domesticated. So it's fun to look at these patterns of where the similarity exists and where the

differences exist. And that really helps to us to inform not just dog history, as Anders was saying, but human history as well. But Gregor, does this suggest that dogs came from a single origin, like one wolf species or were there multiple domestications of dogs that happened that kind of led to maybe these different lineages? That, you know, that's a really good question. And I think this paper goes some way toward pushing the needle further in the direction of only requiring a single population of wolves to explain the variability that we see in all modern dogs and in the ancient dogs in our study. And though we have 27 in our study and additional five from previous studies that we looked at, that's still not a whole hell of a lot of dogs when you consider the number of ancient human

genomes, for instance, that have been published, or the number of ancient horses that have been published. And it is still possible, although perhaps unlikely, it's hard to say, that when we sample dogs from other regions and other times where we have yet to sample, that we may find that there are lineages that, as Anders said at the beginning, we just haven't seen yet, and that might help to push the needle to that question in one direction or another. And Greg, Greg, there was another interesting result about how dogs mixed or didn't mix with wolf populations. Can you kind of explain what's happening there? Yeah, well, and this is really down to Anders's work. What we were able to see is that at several different locations on the planet, you can see a signature of what we

call admixture between local dogs and local wolves. And all that means is that they're swapping genes. There is some gene flow here. There's some sex that's taking place between the local world population and a dog population. Now, those analyses on their own aren't able to tell you definitively which direction that gene flow is going. It could be one, dogs to wolves, wolves to dogs, or both. So what Anders does is a secondary level analysis where he looks at all dogs and all wolves and finds that there is no one wolf population that is any closer in its overall relatedness to all dogs. And what that suggests then is that with all dogs being on one side and all wolves being on the other side, when you look at a more global picture, that all of those local signatures that we are seeing are exclusive of the result of gene flow from dogs into wolves and not the other way around.

And that is, for me, that's absolutely fascinating because that means even as far back as 11,000 years ago, having a hybrid dog wolf was not okay. If you were somewhere between a dog and a wolf, you simply did not survive long enough to pass down that wolf ancestry into all the subsequent dogs that happened. after that. So dogs, the way in which they were being managed, the way they fit into human societies, the way they were being cared for, required them to be extremely doggy. And if you had any wolfiness about you, then you were just not okay. And you were probably hit on the head and sent away because that was just not accepted. All right. Anders, what's your interpretation of that? Yeah, I agree. And I mean, I think it's a kind of fascinating thing about dog genetics. I think a lot people might have this intuitive idea that there will be a kind of a grace zone, a kind of gradual

transition between dog and wolf. But actually, at least for these up to 11,000-year-old dogs that we have studied, there's basically no question. There are fully dogs already by 11,000 years ago. Of course, if we go even further back into the past, you would at some point reach a state where you have something that is kind of in between. But all the ancient dogs that we have studied already by 11,000 years ago, they are kind of fully formed with dogs. They are not some kind of intermediate stage. Or I guess the question is, I mean, this is purely speculation,

but why are dogs special then? Why do we have this special relationship? Why don't we do this to a cow? Well, so I think what that question presupposes is that we were doing something with an intention with a long-sided view toward achieving a goal of a Labradoodle on your couch, however long ago.

And I think that that underlies a lot of domestication, or at least the popular conception of domestication. And I think instead, what I prefer to see this as is much more likely within an evolutionary model, which is where both Anders and I come from, is more of an emergent process that comes out as a result of the interaction between wolves and people. And it's not that either the, it's not wolf led, it's not people led. It's just two species getting together and then becoming increasingly reliant on each other for their survival. And not just a species, a specific population of that species.

And we see lots of examples of this, that involve humans and other animals, but lots of two other animals as well. And there's all kinds of words within evolutionary biology to describe these kinds of relationships between things. And I think a dog is just another example of this. But because it involves us, we want to think of ourselves as the people who are going into the dens and grabbing a puppy and deciding, yes, we're going to turn this in something cute that our four-year-old can play with. So without being eaten, which is a whole other thing. I mean, why would you, you would never do this intentionally if everything is wolf and you have no concept of what a domestic animal is?

So I think there's a lot more accidents and byproduct in this whole process than there is any sort of top-down intentionality on the part of people. Right. And Andrew, now there are many different breeds and cross-breds like a Labradoodle. I mean, what is a breed exactly? Yeah, I mean, I think a breed isn't necessarily something very special. I mean, it's basically just a population of dogs that has been, through human design, genetically isolated from other dogs. And so the mating is controlled to prevent unwanted, so to speak, DNA from entering that population. And then there's often selection to achieve certain types of traits or characteristics. But there isn't really a fundamental difference between breed dogs and non-breed dogs. You know, they have the same roots, the same origins. It's just that humans sometimes have created these artificially isolated populations

to control their evolution in a much more directed way. But that's basically it. Who knows if all of these breeds will remain genetically isolated from each other in the future? I don't expect that it will have a particularly large impact on the kind of long-term trajectory of dog evolution. I'm Alex Salem, and this is Science Friday from WNYC Studios. And Anders, even though there are a lot of breeds, the dogs are less diverse than they were in the past.

Is that correct? In some sense, yes. at least in certain parts of the world, not necessarily on a global scale. A lot of the early diversity that we found, let's say, 10,000 years ago is actually represented. It has kind of mixed and transformed itself in different ways. When we look at ancient dogs in Europe, there was actually much more diversity in the past. So European dogs before, let's say, four to five thousand years ago, actually displayed a much greater diversity on a genetic level. You had some European dogs that were similar to near eastern dogs,

others that were similar to Siberian dogs and that whole range in between. But when we look at modern European dogs, they only display a fraction of that early diversity. So at some point, through a process that we don't understand, this diversity basically collapsed in Europe. And perhaps it was a single population that basically expanded and replaced other European populations. Gregor, if someone is sitting at home listening to this with their husky or their Labradoodle or Cocker Spaniel, I mean, how does that dog fit into this? What should they take away about their pet from this? I think that they can be, you know,

everybody's got a different relationship with their dog. And by and large, and we can see this for some really great research that's been done on dog cemeteries recently. And that for a lot of people, a dog is a member of your family. And that you grieve it in the same way that you would grieve the death of a family member. You take care of it in the same way that you take care of a family member. And it means, you know, if you're having, if you have kids, they help to raise the kids and teach them all kinds of things. And there is a real, and a lot of societies, there is a real attachment and association and importance put on having a family pet that includes a dog.

And I think if you're sitting at home, the thing that you can take away from this is that we know from this study that that, how you're feeling about your dog right now goes back at least 11,000 years and probably deep, much deeper than that. and that therefore there is this sort of unbroken attachment and emotional connection that you share with your dog, that you know that your ancestors, whose names you'll never know, who existed in lots of different parts of the world, all share that same sort of emotive, empathetic reaction. And I think that's certainly true of more than any other domestic animal. No matter how much you care about your guinea pig, it's never going to have the same depth of history as your dog. So I think that's one of the big lessons from this. Gregor, I'm not trying to start something, but how does this all compare to you?

a cat domestication in evolution? Cats are great. You know, you can feel good about your cat. And evolutionarily, there's some really cool stuff going on with cats where, you know, you can buy a Bengal cat or a savanna cat, which are intentionally bred not just with other cats. Like a Labradoodle would be a Labrador and a poodle, and that's two dog lineages, where you have cats that are bred with completely different species and the way and to create these kind of weird novel mix-ups of things. And we're not doing that so much with dogs. So cats have their own kind of unique weirdness about them as well.

But cats are in terms of living in houses and having that kind of relationship that we associate with dogs, that is a far more recent process. And my understanding is a lot of that has to do with kitty litter, is that you only start to bring in a cat when you allow it to go to the loo inside your own house. And that really only happens around World War II, maybe just a little bit after that. So when we're thinking about time depths, again, dogs go way, way back. And I'm not, you know, a lot of dogs are living outside the house, too, but the overall kind of the style of relationship or the big thing that allowed for people to feel as closely to their cats as they always felt to their dogs. Really is only about 50 or 60 years old. Really? It's kitty litter.

Yeah, yeah. Well, we've run out of time. I'd like to thank you both. Anders Bergstrom, a postdoc researcher and the ancient genomics lab at the Francis Crick Institute in London. And Gregor Larson is the director of the paleogenomics and bio-archology research network and a professor of archaeology. at the University of Oxford in England. Thanks a lot. Thanks to the opportunity. For Science Friday, I'm Alexa Lim.

And that's about all the time we have for today. One more thing before you go and before 2020 ends. I wanted to share a special thank you to everyone for listening, participating, and supporting Science Friday, and your local radio station. 2020 was challenging in so many ways, wasn't it? But it also showed us how much science and community. mean to all of us. Year-end donations are an important part of how Science Friday

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