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With Kai Wright, available wherever you get your podcasts. Hello, I'm Lulu Miller. If you joined us last week, you met the hidden body part stowing away inside your body. And today we have another hidden story about life and non life and how the line in between them is way blurrier than we might think. We are talking about viruses today. This episode is a rewind, but it's a lovely one. It's called shrink. And what I love about it is not just that it busts a binary between life and non life that I always thought was hard and fast, but also that as you listen, it really feels, at least to me, like Robert Crowich and Jad Abumrad OG hosts that they kind of shrink down into these little boys who are so giddy with questions for Carl Zimmer. I picture them like two little boys at Santa's Knee, just taking in the knowledge. And it's a really raw, lovely glimpse, I think, at what this show does best when it does its best, which is to make space for questions and for real listening. So I hope you enjoy this kind of giddy romp through the evolution of life and non life and all the places where that line blurs out a bit.

Here we go.

Wait.

You're listening all right.

You'Re listening to.

Radio lab radio from Wnyce Rewind. Come on. Totally. You guys came saying we want to talk to you about three.

Okay, let's do that. Hey, this is radio lab. I'm Jadab. Umrad, we're going to do something that's a little bit unorthodox today, at least for us. If you've listened to the show in the last ten years or so, however long we've been doing this, you understand that, like, we like to edit, right? We like we like a good edit or 70. But today I want to play you something that has almost no edits at all. It's just a conversation, which is, of course, the foundation of what we do, these long, rambling, occasionally profane, error strewn conversations that we then edit into something coherent. But today I want to show you the messiness. No edits. This is a chunk of a conversation with science writer Carl Zimmer. He came and sat down with us a while back and we talked for 4 hours. Two of those hours became the basis for the CRISPR podcast. That was a few podcasts ago. This was about gene editing. But then we kept on going for another 2 hours, and he told us this story, actually two stories, but we're only going to play one that I thought was really cool, and it's about this new way of looking at life.

Is this a long story, a medium story, or a short story.

We can get through this a lot faster than CRISPR.

Okay.

I really like CRISPR, by the way.

So do I mean, CRISPR is yeah, it's the bomb. Yeah, that's perfect way to describe biological bomb.

Okay, so chapter two.

Maybe you could start the story once the once upon a time.

Sure. So once upon a time being I'd say once upon a time being before 2003, we basically had two kinds of living things on Earth. We had cellular life and we had viruses. And it was nice and distinct and clear cut. And so cells included us because our bodies are made of cells and bacteria, which are single celled, and all the other things that can grow and let their cells divide. They have DNA, they have proteins in them, they all that stuff. And then over here, you had viruses. And viruses were just little packages of genetic material that would go from cell to cell and use the cell to make new viruses. And so inside of them, all they had were genes and a couple of proteins that would then sort of hijack their host.

They seem like so preliminary that they don't maybe not even qualify as life.

Right. They can't grow on their own. They can't generate their own energy. So us and all other cellular life, we make kind of a fuel called ATP, and we need that to do every little thing in our body. And viruses don't make ATP.

So couldn't we say that life is us, cells and multicellular beings? And then there's sort of pseudo life, which is these little things that live off of us.

Yeah, a lot of scientists don't really think viruses are truly alive, even. They just sort of take advantage of life to make more copies of themselves.

Okay, can I ask a dumb question? So viruses, they don't have a wall around them in the way that cells are walls essentially are walled off areas.

They might have a protein shell. When the flu virus goes into a cell, that protein shell kind of breaks open and the genes and proteins inside come out.

They do have containers that contain them for a while.

I see.

Well, isn't that one of the somebody who had a list of rules that make you alive and wasn't a container? Was one of those rules? Yeah, they don't do the energy, but they have the container at least.

Right. So the problem with viruses is that they have some of the things that we think are essential for life, but not quite all of them. So it's been convenient just to say viruses are not alive, put them over there, because they don't have everything that cellular life has. So we'll just say they're not alive.

They'Re just viruses gotcha.

And then so then what happened is that there was a scientist named Timothy Robotham in England who was investigating a outbreak.

Timothy Robotham?

Timothy Robotham.

That's a good English name robotham with.

A fuck timothy robotham was working in bradford, sydney, in england, and he was looking at the kinds of bacteria that might be growing in a hospital, like they were having some problems with pneumonia outbreaks and so on. And he was like, okay, what's growing around here? And so he went to sort of a cooling tower for water on top of the hospital, and he took a sample, and he went and put it under his microscope, and he's like, some interesting bacteria here. Oh, here's a very interesting bacteria that doesn't really look like anything I've seen before.

Wait a second. This guy would just kind of crawl around to weird places and just snatch little snippets of scum or what would he?

Yeah.

What was he what was his job?

He's a microbiologist.

Oh, of course.

So it would be good to know.

Is that what microbiologists do? They just go scrape little bits of rock or water tower, search the world?

Yeah, I mean, microbes are everywhere. So microbiologists go everywhere to find microbes. So they're even in a water tower on a hospital.

Was he in a kind of an investigatory role? He was trying to help them help them figure out which bacteria are making people sick.

That was one of the hopes. But he was thinking of doing a survey because there are diseases like legionnaire's disease, which can grow in these sort of containers of water. There's some concern about that. So better to get to know what's growing. So he's particularly taken by one thing that he assumes is bacteria. And it's got a kind of interesting kind of roundish shape. And when bacteria around, you can call them cockeye or caucus. So he names this bradford caucus, gives it a name.

That's why the caucus name comes up. It's referring to the shape like streptococcus. Is it because it's round? I did not know that. The things you learn. Talk to carl zimmer. My god. Okay.

So he's trying to study this thing. When you're a microbiologist, the way you study bacteria is you get him to grow, and he can't get this to grow. He's feeding at things, and it's like, it's not growing. Why is it not growing? I can't figure it out. And eventually he just hits a wall. And unfortunately, his lab got shut down. And so he basically said, okay, I don't want to throw this stuff out, so I'm going to give it to some of my colleagues in france.

It wasn't dying, which wasn't growing.

Yeah. So he gave it to a scientist named bernard lascola and his colleagues, and they kind of put him he just sets it aside for a while, and it's just more bacteria. For some reason, he decided to take a look at this bradford caucus. What was this thing that robotham was talking about? So he looks at it and he says, okay, this is the size of bacteria, but it looks like a gigantic virus.

What is a gigantic a virus is usually very small.

Exactly.

So bacteria to a virus is like.

Hundreds of times bigger.

Hundreds of times.

Okay, so it's a Queen Mary to a small dinghy.

So he looked up close and he was like, what is this thing? This doesn't look right. If I didn't know better, I'd say this was a virus.

He's saying this based on its internal orientation, its appearance, because it had the protein thingy, it had stuff.

So a lot of viruses, they have a shell made of protein, and the shell is kind of composed of plates, so it kind of looks like a soccer ball. So it's a very distinctive look.

Okay. And it looked like that?

It looked like that didn't look like bacteria.

Oh, interesting.

It's like, wait a minute, could this be a virus?

So this would be like, maybe like finding an enormous soccer ball in the woods?

Yes.

So he'd found the Leviathan equivalent of a virus.

Right. It didn't make sense. It was kind of crazy in that microscopic realm to say, maybe this is a didn't.

So, Brad mumford, what's his name again?

Timothy robotham.

Robotham didn't have this realization?

Nope.

He hadn't looked at it closely enough? He looked at it, but he just didn't somehow put that this is a virus.

It didn't click for him.

Wednesday, that's a virus day, and this was Tuesday.

And it's likely that other people were looking at these same things in years before.

I'm thinking they were bacteria. Interesting.

Here's something the size of bacteria.

Well, in fairness, because viruses are always small, then you wouldn't think a big thing would be a virus.

Well, viruses are always small in the sense that they were discovered because they were small. So basically what scientists did was they discovered viruses by filtering fluid from a sick plant or a sick animal through a filter. Porcelain, actually. And it was so small that anything the size of bacteria got trapped in the porcelain and anything smaller came out. And lo and behold, they could find things that could cause sickness in that fluid that passed through the filter.

So the discovery of viruses meant it was innately small because that's how you filtered for them.

That's what they were looking for.

That's interesting.

So there were probably generations of scientists who were looking in through microscopes, saw some interesting round thing and assumed it was bacteria and it was probably a virus.

What the fuck is this giant, giant Leviathan virus? I assume that was his question.

Well, I mean, first he had to really establish that it was. And so what happened was that he looked very closely at it and kind of worked out its chemistry. And the more he looked at it, the more it looked like a virus. They started actually looking at its DNA, which hadn't been possible before. Turned out that its DNA resembled the DNA of viruses and not of any known bacteria. It actually didn't have the equipment for making fuel inside of it. And then the real kicker was that he found out how to grow it. What he had to do was he had to stick this thing inside of amoeba and then out of the amoeba would come more Bradford Caucus.

Just like a virus.

Exactly like a virus.

You need to change the name from Bradford Caucus to something else.

Right. So they named it Mimi virus.

Mimi virus.

Mimi virus. Because they were in France and Mimi is in a French opera because it was a mimic.

It was mimic.

It was a mimic, yeah.

Interesting.

Mimi like a mini me.

Mimi. Is that like a French word for mimic?

I think they just took the beginning of mimic and added it to virus.

Mimi virus. Very nice.

I guess it's the same thing twice. Mimi. It's like mimic. Yeah. Okay, I get it. Interesting. Yeah.

This was really bizarre when they published the report on this in 2003. And then people really scratched their head because remember, ordinary viruses have maybe ten genes. This one had 1018 genes in it.

Wow.

When you have ten genes, those are genes that tell you have a protein capsule and so you can swim through the thing. So when you land on a cell, you can burrow in and then explode and then make babies. There's not much to being a virus and you just need a few genes for that. Why would you need thousand? What would you say?

Does this thing have particular talents that the other viruses didn't have?

Yes.

Maybe it was like it does.

It does.

Oh, it does.

Okay.

Well, so one thing that's really interesting is what happens when it goes inside its host an amoeba. It goes in, but instead of kind of shedding off that protein code and just spilling out its contents, it actually goes in and stays as it was.

You mean it stays like in a container and everything?

Just sort of yeah, it's called a virus factory. Once it's inside there, it's this thing they call the virus factory. And it basically is able to components come into it and then it has enzymes that can refashion them and then outcome the components for new jobs.

It doesn't have to go into the nucleus of the already existing cell?

No, it just floats in there.

Oh, interesting. So what does it do? Like open a portal and then it sucks up some stuff?

Yeah, it has this beautiful sort of they call it a stargate because it's a doorway shaped like a star and things come in and then out another stargate. These sort of manufactured things come out and then in the cell they assemble into new giant viruses.

So it spits out the raw materials and that then self assemble into a giant leviathan.

No, baby, giant leviathans. Which then how do they get out of the do they explode through the.

Surface of the cell, they just blow out. Yeah.

That's a totally different thing.

Yeah.

I thought normally viruses just go into the machine that's already there because they're parasites. They just use the living thing.

Yeah.

This thing is I have a weird kind of respect for this thing.

Oh, yeah. It's amazing. And one of the amazing things about it is that it can get its own viruses.

Really?

Yes. So there are viruses of viruses. These things are called virophages, and they actually go into the virus factory and hijack it and instead outcome virophages.

Oh, wow.

Yeah.

As soon as you have a virus factory, that's what a virus wants. Now that the virus has its own virus factory, well, it's going to get viralized by the other viruses.

Right.

Weird.

Yeah, weird is the right word, I.

Think, right now, in 2003, you could say, well, this is one weird virus. But the scientist said, well, I wonder what else there is.

Did that create a wait a second. So they said, okay, it's got all this extra genetic power, but it's doing this sort of special circus act here. It's building its own factory and it's just behaving differently from it. So maybe it just needs all those genes to do this special thing of doing.

The problem was that when they looked at these thousand and 18 genes, most of them didn't match anything anyone had found before.

These were new genes.

Genes, yeah. That you couldn't even guess at what they were at.

This has got to be from like this is like an alien. This is from Saturn, this thing. Is that where you're driving with the story?

Not quite, but kind of.

So wait a second. So they look at the chemistry of life as it's known, and they don't find any matches for this little thing, this big thing?

For most of the genes, they couldn't find a match you can look at.

I mean, wow, that's a double mystery. Like, what is this and where does it come from? It doesn't seem to have the smell of Earth life.

Yeah, except that it uses DNA. I mean, it uses protein, it uses our chemistry, but it's doing something weird. And so these scientists said, well, okay, they looked in an English hospital water cooling tower. Let's go look at one here in France. And so they looked and they found another giant virus which was even bigger than the one that they had already found. Where was it?

In the hospital in France? In the air conditioning unit.

It was in another cooling tower.

Jeez. This is a cooling tower phenomenon so far.

Rooftop biology. Well, it's excitement galore.

It's more like the drunk looking for the keys under the is.

Wherever you look, there it is.

We know there was giant viruses found in one water tower, so let's go look in another water tower. Like, that's our safest bet. And hey, look, we found an even bigger one.

Which had an even bigger one.

It was even bigger. Yeah. So instead of 1018 genes, it had 1059 genes. So they named this one Mama virus, mimi's first cousin.

Mama.

Right.

Did Mama do in things in the cells that Mimi didn't do? Or did it also build a it.

Was it was making a virus something. There's a common theme here with these two. Now you have two giant viruses doing the same thing.

The whole stargate and everything.

Yeah. What's weird is that the Mama virus has a bunch of genes that Mimi virus doesn't have and, again, don't match anything.

So they don't know what these extra ones do.

Some of them look like they're involved in building proteins, which doesn't make any sense because viruses are not supposed to do that. So this is all completely confusing. But then they say, like, okay, maybe we need to kind of get away from the whole water tower thing and widen our little where would you go?

The opposite of a water tower would be like the bottom of a well. Or do you go to a library and look in the interior of old parchment books?

No. You start looking at places like you look in the ocean or you look in sediment, or you look inside animals, or you look in the soil, and they start finding giant viruses over and over and over again.

Really?

Yeah.

In all those places. In many soil inside of animals. Like in animals tummies or something.

Yeah. So these researchers went to Brazil and said, let's go look at animals and see if we can find giant viruses. And they found a new species in cows, and they found a new species living inside of a monkey.

And were they finding gianter, giant viruses? The numbers of genes were going up and up and up.

Yeah, they would keep finding new record breakers. The biggest one right now is called Megavirus.

That's the summer movie. Mega virus. Bigger than Mimi, bigger than Mama.

Mega in a world.

In a world.

You got it. That's right. It's like this is like I'm wondering what they're going to do as they keep finding bigger ones, because you keep having to find superlatives for these things.

Well, where was Mega found?

Mega, I believe, was found in the ocean.

And how many genes does Mega have?

Mega has 1120 genes.

Okay.

So it has the most genes, but it's not actually physically the biggest giant virus, which was so this one is called a Pandora virus.

It was found in a box let me guess in a sealed box. And then they opened it and oh, my God.

Well, it has this bizarre shape, like an urn, which is completely nuts. There's no urn shaped viruses. This is crazy.

Did that remind somebody of the myth?

So Pandora's box was actually an urn.

Oh, it was. Okay. I see.

Oh, why did we call it Pandora's Box?

Then god, that's a very learning make.

You happy because you love where they found it.

Where did they find it?

So what they did was these Russian scientists they were collaborating with dug up frozen tundra that had been frozen for 30,000 years. And they said, let's thaw this out and see what's in there. What kind of things have been asleep for 30,000 years?

It sounds like the beginning of a Sci-Fi movie right there.

Among other things, they found Pandora frozen land. They found Pandora virus. And not only did they find it, but when they let it warm up a bit and then they gave it some amoeba to check out, it did its thing. It did its thing.

Wow. And how much bigger if the first giant virus you introduced us to was like an elephant sized mouse compared to that elephant sized mouse, how much bigger is this one? Maybe it's more specific than you want to be.

I need to look at the numbers. But you're kind of going from, I don't know, elephants to dinosaurs. You're getting bigger and bigger and bigger. We're not talking about Pandora virus is bigger than a lot of bacteria.

Wow.

So wait a second. So these things are now being found everywhere you look?

They are incredibly common. They've even been able to get giant viruses out of people.

Really?

Yeah.

Where are you find them?

In a person in our intestines or something?

I believe they found one sample in somebody's lungs and another sample was found in someone's blood. But it's really hard to tell whether they're actually actively invading us and making us sick. Maybe instead of invading amoebas, they can invade human cells because amoeba and human cells are surprisingly similar. Or is it just kind of along for the ride with some amoeba that infect us? Or does it kind of drift in? And when people are sick, their defenses are down. So we don't know if giant viruses have anything to do with human disease. But.

You have a category problem here. If you've got a giant virus, that's virus like in its general shell, but it's making proteins, it's got a bunch of genes that viruses don't have. You're already bigger than some bacteria. Shouldn't we call it as its own separate thing at this point?

That's what people are arguing about right now. I mean, do we keep that line between viruses and cellular life and just put the giant viruses with the viruses? Or do we kind of blur the line a bit?

This feels like it's on its way from one category to the other.

So that's one of the big questions is like, what way did this thing go in evolution?

What does that mean?

Well, how do you get a giant virus? How do you how do so we'll.

Get to the potential answer to that question, which I think is totally fascinating, after the break.

Hi, Rebecca Murray here from Mount Vernon, Washington. I'm a member of Radiolab's exclusive membership program, the Lab. My membership provides Radiolab with a steady source of funding so the team can continue to tell stories about our crazy world. And I get access to exclusive live events and bonus content. Join me in supporting the show we love. Sign up@radiolab.org slash join.

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The New Yorker Radio Hour.

Bradley Cooper in his new film about the conductor Leonard Bernstein, cooper had to conduct one of the world's top orchestras. For real.

Scariest thing I've ever done by far. I mean, not even close. Singing at the Oscars, live, performing at Glastonbury. Nothing even comes close.

Bradley cooper on Maestro. That's the New Yorker radio hour from WNYC Studios. Listen wherever you get your podcasts. Hey, Jad. Here. Radio lab. So we're going to return to our conversation with science writer Carl Zimmer. It's an unedited conversation, and we were talking about giant viruses and what they can teach us about life, which really starts with a simpler question of, like, where the hell do they come from?

How do you get a giant virus? How do you how do you well, one clue comes from those genes. So now that they're finding more and more of these giant viruses, they're finding enough variety of them, they can look for some common genes that they share, some common mutations in genes. And they're finding, actually, that it looks like giant viruses might actually belong to one lineage.

Oh, interesting.

Those are their cousins. They have a common ancestor.

Yeah.

Tribe of A.

And if that's true, it could be an incredibly old tribe. These giant viruses could be a lineage conceivably that goes all the way back to the early stages of life, the.

Dawn of time in a world in a world it's really old, like back to the very beginning of life on.

Earth, to that era. Yeah. I mean, maybe when cellular life was getting started. But the question is, well, what were the giant viruses like then? Now some people have said, well, no, giant viruses actually started out as teeny tiny viruses, and they've just been, like, gathering up new genes through time and just been getting bigger and bigger and bigger. But a number of the people who actually study giant viruses and have really helped us to understand the most are saying, no, we don't think so. We actually think that these things started out as cellular life. They were cells. They were full blown cells.

Oh, you mean they were from the other side of the road. They were cellular life and then what? They switched sides?

Yeah. They changed teams. Yeah.

I can't have a plant that becomes an animal.

So they started off as, like, what we would call creatures.

They started out truly alive, free standing.

Out there in the air or the water or the ground.

Yeah, just like some free living microbe.

Why would you go demote yourself?

This is your problem with parasites. You keep saying mean things about parasites. How many years have we been talking about parasites? Tell you nothing.

If I had a choice between being having my own integrity and choosing to make a living on my own or to suck off you, I would just live on my own.

Excuse me for hold on.

I know you like parasites, but honestly.

Could you not use that passage recording, please?

It's already been cut. Wait a second. According to this theory, you have a microbe.

Stands true.

Nevertheless, we have a microbe that is doing its thing and then something happens. Okay, but what is the something?

It becomes a parasite.

It becomes a parasite.

Or at least maybe a symbionte. Basically, what it does is it starts living inside another cell.

You mean it gives up its integrity as a free life form. A freestanding life form.

Just so we understand what that means. That means that it's got a shell, it's got a border. It's making its own energy. It's replicating in the way that at.

The beginning at the beginning? At the beginning, it can make its own energy. It can grow, it can divide, it.

Can do all the things that living things do.

Yeah.

And then for some reason, it chooses to require some other creature's existence for its own. It has to become dependent on some other organism for its very, very existence.

Well, let's flip it the other way and say it discovers a wonderful new home inside of another cell. It comes in and is like just.

Like, I love leaving my Park Avenue apartment for a dark cave. It's a new and exciting.

Contra. Let's imagine you're like bare grylls, okay? Let's imagine you are like hiking around and killing your own food, okay? Let's try to picture this, okay? Robert doing this. You're gutting your deer. You're starting your own fires. You're going on and on and on. And you do that for like a few years and you're walking through the jungle.

You're very skinny because it's not going well.

So Robert Kroich, the haggard hunter. And let's say you're doing this in Minnesota, right? So it's like cold, okay? And then suddenly there's a break in the forest and you come across a giant mansion. And you're like, what is this place? And you open the door and inside there's like conveyor belts with ice cream and steak, and there are slippers waiting for you. And anything you need, somebody else is taking care of it.

There is one thing you left out. When I walk into this magical kingdom of soda, it doesn't let me out. I can't leave ever again because I am become so dependent on its natural wonders that I lose my independence, my integrity. And the very, very thing that I walked in with is now gone.

We did literally have this conversation a few years ago.

We did.

It's true, we did. And I did point out to you at. The time that you are quite dependent on other species. Do you want me to bring up no, I will just say, see episode.

32 or whatever, eyes will roll right out of their sockets.

Being able to take advantage of another cell, evolutionarily speaking, is a great way to go because you have all these things taken care of for you. Now, according to this theory, these mysterious ancient microbes started going into these cells and reproducing there and then going out again and then finding another host cell to infect.

Okay. Were they making their hosts sick?

Probably, yeah, probably, because giant viruses are not good to get.

Well, see, this complicates your mansion metaphor just a tiny bit, because what it means is that you go in the conveyor belts and you're feeding yourself and you're having a good time, but then your filth starts to muck up the place, and it starts to collapse from within. That doesn't sound so nice to strain.

The metaphor a bit.

Go boy, go boy. Robert Crowd referring to me now. It's for him.

Okay, I'm just trying to understand.

So you spend some time in this wonderful mansion. You rest, it's warm, it's comfortable, so on.

You eat, fill it with your filth.

You start a family, and then all of a sudden, you and your descendants leave the mansion. The mansion just collapses from all the damage you did to it. But actually, you see in the distance, there's another mansion. Let's just go over there now. You feel, like, rested and ready and like, yeah, all we got to do is get over there. So let's just go there. We don't have to stop to kill a deer. We just go to that next mansion. The ice cream is waiting.

I still got to walk, so I need my legs, so to speak sure. To get to the next mansion.

Right.

But I don't need the powerful muscles that I would have needed to kill the deer. I can let go.

Let's say that you don't even need the knowledge of how to kill a deer.

You could be blind, dumb, and fat.

That's where you so these things destructive.

I'm so excited.

They start getting rid of these genes.

And how does that happen?

Just a random mutation comes along and just cuts out a bit of DNA.

Because it doesn't need them.

You're fine. Yeah. You're like that's? Okay.

Is it a moment where, oh, there goes a big chunk of me gone, yeah, I don't need that.

That's a regular kind of mutation that happens all the time, really, in cells. Oh, yeah.

But then your successor being just travels a little bit lighter and is able to succeed just as well.

Right. So if we are born with a part of our DNA that's deleted, that had some hemoglobin genes in it, like, good night, that's bad. But if you cut out a gene that this giant virus no longer needs because it's got everything supplied to it in its host. Fine. So let's chuck that. Chuck it out. So the idea is that these viruses, they're giant viruses, but they've actually been shrinking.

How fast does a giant like the imagining back in the beginning, there was not mega cellular not gyno there's a cellular being.

Right.

Oh, a cellular, right, okay.

Cellular being, cellular, all of the privileges.

And joys of independent life size wise, it's a blimp. It's a massive thing. And then suddenly it starts to shrink bit by bit by bit by bit. At what rate does it start to shrink and shed itself?

Well, it could be that these giant viruses we're finding, these giant viruses that scientists are finding could be shrinking very, very slowly. It could be that there are other viruses that made this transition that shrank faster. So maybe it's a race to the bottom. Maybe some some maybe some tiny viruses are just former giant viruses that just shrank really fast.

Race to the bottom. It's such a different way of thinking about life. You generally assume, being a multicellular organism yourself, that little things, in some deep sense, though you're not supposed to say this want to be big things.

You don't want to say this, I.

Know, but most people, unlike you asshole, most people think that it's better to be more complex than to be simple. But here you're talking about a different voyage altogether, that it might just work out for you to be simple rather than complex.

Well, given that viruses are insanely abundant on this planet, I mean, there are, by some estimates, ten to the 31st power viruses on earth. Think about that. It's a one with 31 zeros after it. It's inconceivable how many viruses there are on earth.

So it's their world.

So apparently nature has not agreed with you. But it is interesting, like thinking about how life gets smaller and simpler.

This is interesting. Yeah. If it's true that this trajectory is as common as you say, that things start out sometimes start out big and then learn to live inside other things and in the process get smaller and smaller and smaller. And this is actually maybe what happens to a lot of viruses. Not just some viruses. In a way, it gives the virus an honorable history. I don't know why I feel that way.

This boy isn't going to sign up for that.

No, he's not going to sign up for that. And I don't.

That's okay. Well, an honorable history. But then, I mean, it abandoned its free living path, right?

It did.

It gave in to the temptations of the mansion full of steak and ice cream.

It's true. But I've always assumed, and this is not something one should assume that viruses were a kind of proto organism. They were somehow at the beginning of something and they never quite got going. Yeah, but you're actually saying that these viruses are, in a way, at the end. Not at the end, but they're at the I don't know how to quite use the words that I want to use. They feel somehow at the end of something not at the beginning. Like, you just took what I consider to be the beginning, and you've now made it an end.

An end.

And that's interesting.

That's very interesting.

Yeah.

Very interesting.

So life can go in different directions.

And how far can that reverse journey go? I mean, can you go from, like, how big did that was it ever like a turtle with things or no. Like a giant dinosaur? No, sorry.

There are things called I believe they're called mixazoans, which started out as free living animals and have become parasites. And they're just down to just a few cells.

Mixazoans, you say free living animals. You don't mean animals in the way that animals. Animals. Anyone would think of an animal like a jellyfish. Oh, look, my pet. My pet Fluffy. Not like that.

Well, my pet jellyfish.

Really?

Really?

Yeah.

So you're saying a jellyfish sized thing has now reduced itself to a tiny.

Speck, microscopic parasite of fish?

Get the don't even say it. Because you can't do it if you're that small.

That's insane. Really? Going from something you can see and would want to avoid while swimming down to something that you might even just breathe in without even knowing it.

Wow.

You're blowing my mind. Shrinking my mind.

What was it called again?

Mixes.

Mixes Owen.

Mixes Owen. Yeah.

How do you spell that?

M-Y-X-Z-O-A-N.

I'm trying in my mind to construct a scenario where we, like the Mixes Owen could begin to shed. Like, if we were living inside not the iPhone, but the I home. The I universe.

Well, but the fact is that we have cast aside some things.

What have we cast aside? Well, we can't we used to smell better. I know that smell better.

We used to be able to make our own vitamin C in our own bodies. Our own bodies were vitamin C factories.

Really? Yes. What changed that? Why did we want to let go of that?

That sounds great, sunshine. Vitamin C. Yeah.

Making your own supply of vitamin C. Well, if you are sitting around eating fruit all the time, fruit, which is loaded in vitamin C, then if you get a mutation on your vitamin C gene, well, you're fine because you're getting your vitamin C from somewhere else. You don't feel that lack. You don't start getting scurvy because you're feeding yourself on fruit. And then that mutated gene may then spread out and end up being in every member of your species, which seems to happen to us. I mean, you can literally see we have these broken vitamin C genes, so.

Sometimes we shrink, too.

Yeah.

Okay.

So there you have it. A raw conversation with science writer Carl Zimmer about shrinking shrinkage in life. Now, usually what happens in these conversations is because you're just talking and because you don't really have like an encyclopedia sitting right next to you, you get a lot of the little things wrong. Little details, little facts, names, dates, whatever. And then, you know, you fact check it later. So in fairness to Carl, as we were fact checking, we gave him the chance to listen back to the raw conversation, make a couple of amendments.

This is fact checker. Carl Scolding Rambling. Carl. Okay, so, okay, we were saying that this microbiologist, Tim robotham took his samples to France, but actually there was another microbiologist named Richard Bertles that did it. Got. You. So small but important.

Sorry, Richard.

Our apologies. And Mama virus turns out to have 1023 genes, not 1059 genes. My apologies. Then I started talking about megavirus. At the time, in 2011, it was indeed the biggest virus known. 1120 genes. Okay.

Okay.

However, there was in 2013, another virus found called Pandora Virus. Now, I was saying that this was something found the Siberian tundra. Wrong. This was found in the ocean. And this virus has a whole lot of genes.

How many?

It has 2500.

Whoa.

2500? I mean, that's way more than a lot of bacteria.

Also, at a certain point, we refer to Pandora virus as being the biggest virus in size. Actually, that distinction goes to Pithovirus. And also, it seems that since we talked, there's evidence that there might actually be a couple separate lineages of giant viruses. 1 may have evolved from big to small as we talked about, but another one might have gone in the usual direction from small to big.

There's one last thing that I see. So apparently I didn't quite spell mixazoan correctly. This is how you spell mixazoan. M-Y-X-O-Z-O-A-N. Apparently, I missed one of those. O's, I can't remember.

I mean, I would be lying if I say I didn't think a little bit less of you now. Okay, extra o back in the raw.

Stupidity that goes into Radio Lab. Stupid people interviewing stupid people.

About smart things.

That's funny.

That's a great tagline. Okay, that's our new tagline. I'm chad abumrod. Thanks for listening.

Radiolab was created by Jad Abumrad and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co hosts. Dylan Keefe is our Director of Sound design. Our staff includes simon adler, jeremy bloom, becca bresler, aketti foster keys w, harry fortuna, david gable, maria PaaS gutierrez sindhu nyana sambadam, matt kilty, annie McEwen, alex neeson, alyssa jong perry sarakari, sarah Sambach, ariane wack, pat walters and molly webster with help from timmy broderick Our fact checkers are Diane Kelly, Emily Krieger, and Natalie Middleton.

Hi, my name is Michael Smith. I'm calling from Pennington, New Jersey. Leadership support for radiolab science programming is provided by the Gordon and Betty Moore Foundation Science Sandbox Assignments Foundation Initiative and the John Templeton Foundation. Foundational. Support for Radio Lab was provided by the Alfred P. Sloan Foundation.