We’ve become pretty well-acquainted with viruses in the past few years. (Thanks, worldwide pandemic.) This week, Katy and Laura take a deep dive into what a virus is, really. It feels alive, but is it? And how do they affect different species and their evolution.
We’ve become pretty well-acquainted with viruses in the past few years. (Thanks, worldwide pandemic.) This week, Katy and Laura take a deep dive into what a virus is, really. It feels alive, but is it? And how do they affect different species and their evolution.
Laura: [00:00:00] Hello and welcome to For The Love of Nature, a podcast where we tell you everything you need to know about nature. And probably more than you wanted to know. I'm Laura
Katy: and I'm Katy. And today we're gonna be talking about viruses. And though they are technically non-living viruses do have a huge impact on living organisms and their evolution.
Laura: woo, It's, it's appropriate time to talk about this because of, I mean, not just the pandemic, but but also the time of
Katy: world turmoil for the last few years. It's fine.
Laura: They're a big deal. They're a big deal.
Katy: Yeah, Yeah. Tis a season. Tis a season, I guess.
Laura: Just, just the season. Season.
Katy: Oh Oh goodness. Well, can we do some nature news cuz I have some crazy nature news
Laura: Yeah it hit me.
Katy: crabs. Not the not the STD d the species. So Alaska has officially canceled snow crab season because officials are trying to [00:01:00] investigate and figure out where the heck about a billion crabs have gone, which is insane.
So
Laura: one lose a billion? Anything?
besides like plankton.
Katy: yeah. Yeah. Right. And it's, it's crabs. So just a billion
Laura: and snow. Crabs are not small crabs.
Katy: no. And they're only in a particular region in outside of Alaska anyway. So the Alaska Department of Fishing game has, for the first time in, in state history ever canceled the winter snow crab season and the bearing straight do their falling numbers.
So if you like crab, don't expect
Laura: there are like, it's that, or they're just a billion off. Like they're ca somebody
Katy: re some intern. Yeah, some intern has messed it up for
Laura: Terrible.
Katy: where they're saying like an estimated 1 billion crabs have mysteriously disappeared in two years. So they have kind of watched it go down the last couple years, but it's like a billion. It, yeah, but it marks a 90% drop in their [00:02:00] population, which is, that's no good.
So they're not sure. They have a, a few different guesses if, because of hello climate change did they , the article says, did they run up north to get to colder water? And I just imagine like a billion crabs running cuz they're, cuz they're, first of all, they're not gonna be like, like running crabs on the, you know, on the ocean floor.
I just, I don't know, that's
Laura: I mean, or it like a billion crabs I feel could make like an underwater, like a tidal wave.
Katy: You would think a
Laura: a you just see a ripple on the surface from a billion crabs running
Katy: yeah. Billion crabs running. I feel like that's like a
Laura: a song title. Absolutely. I thought the
Katy: billion crabs running . They also don't know if the crabs would cross the border . Did they become, are they Russian now? Did they walk off the Continental shelf?
Laura: And then what happens to them?
Katy: I don't know, I guess star in their own role of a BIS three. I don't know, I'm [00:03:00] not sure. Cuz I, I said the same thing. I was like, okay, so if they fall off the
Laura: Like,
Katy: they ? Yeah.
Laura: They're swimming. They're
Katy: Yeah. Cuz then you imagine then you imagine like a billion crabs and then all the fish down, they're like, what the hell?
. Cause it's just like a billion crabs everywhere. Oh goodness. So yeah. So they're looking. But it, but those crabs that, that's really
Laura: Or like just one giant suicide pact
Katy: Yeah. of a billion crabs. That's why they went off the shelf. Just like it's getting too warm. No one's listening to us. We've tried to tell 'em for years. Let's go guys. And they're just like,
Laura: can't take it.
Katy: But they do think that disease is a possibility, but they're really not sure. I mean, obviously because things are
Laura: crabs, crabs that got crabs.
Katy: Yeah. But so climate change obviously is what they're pointing at. I mean, we all know that our water is getting warmer and it does not take, everybody [00:04:00] thinks It takes Oh, it's gotta be 10 degrees,
Laura: not boiling the crabs.
Okay
Katy: It does not take much of a temperature difference for us to kill out an entire species.
Laura: Well, just think about it like, I mean, the difference between 72 and 74 in my own house is a
Katy: is a huge difference.
Laura: lot's enough between being comfortable and uncomfortable.
Katy: And they've been, they've been recording that, the bearing strait has been getting warmer and so that's why they're like, man. And, and there are, I mean, it's, they're, they're cold water crabs. Like they need that freezing
Laura: I can't even imagine the poor, crabbers,
Katy: I know
Laura: that's a lot of money to lose an entire year of income.
Katy: Right. Yeah. So, yeah. We will hopefully, I don't know, hopefully scientists will have, Yeah, just find, Is anyone saying a billion crabs or missing or
Laura: We should put up, we need to put up like, wanted post or uh, missing, missing crab posters.
Katy: Do we have any listeners in [00:05:00] Alaska? I think we do.
Laura: Please, please send us or please post
Katy: Missing crabs. All right, hold
Laura: Have you seen
these missing crabs?
Katy: Yeah. So what we need in Alaska and listeners, does anybody know any, Oh wait, wait, no, we have two. We have a few different people that live in Anchorage, Alaska. So if they are listening to this episode, cause I can't see whenever, what episodes you're listening to, but yes, we will help you make missing.
missing crab Missing crabs. Oh goodness. Alrighty. So do we wanna talk about viruses then?
Laura: Yeah, let's
Katy: I mean, while we're on the subject of crabs,
Laura: right. Or diseases that might be wiping them out.
Katy: Yeah. We're gonna bounce back and forth on this episode a little bit. Laura's gonna give you a little bit of an overview of viruses, and I'm gonna talk about different types.
And then we're gonna go back to Laura. And then after that we're gonna talk about, I'm gonna talk about one, Laura will talk about a different, one of a virus that we picked that is [00:06:00] affecting evolution,
Laura: Right. And act, actually, I learned quite a bit about that part. And man, boy did I have some serious flashbacks to AP bio with this one. I specifically remember learning about like the bacteria fas and all that.
But anyway okay, so overview of viruses. And so you, if you all remember Katy said that they're, technically non-living. What are they then? The term the, or the word virus comes from Latin for a slimy liquid or poison, which I think is cool, slimy. And
they weren't really actually studied until the 1890s, which I guess makes sense because it's not like you can see
Katy: Okay.
Laura: They're pretty small and they are known as infectious. So they're an infectious, not organism, cuz they're not alive like an infectious thing. That infects plants, animals, and bacteria. They will infect things and those things are called hosts. There's other things called [00:07:00] vectors, which are like the middle man for viruses.
Yeah, like from the virus. It carries the virus around and infects the host like mosquitoes. Some are limited like to specific species and other ones have a wide range and can even jump from, animals to humans and things like that. And once they have become infectious, so if they're just these things out there in the environment, they're just a virus.
But as soon as they be infect something, they're then called a virion, which actually I don't think I knew.
Katy: I was gonna say, I don't remember ever.
Laura: Yeah, nobody ever talks about virions.
Katy: Yeah. Or you know, the practical things that we need to
Laura: virus is a benign thing. They're typically small and simple. Okay. Well they're always small. I guess it's relative of how
Katy: Yeah. Yeah. Dear God, don't, tell me, they're big
Laura: thankfully. Yeah. And what makes them technically [00:08:00] non-living is that they can only multiply in living cells, so they're not free living. This prevents them from being considered an organism.
However, some of these viruses as I'm Katy, you might even talk about get pretty although they're called simple, some of them are pretty
Katy: Yeah I talk a little bit about it. I don't go too into detail cuz I was just getting way too into the
Laura: Yeah. Yeah. Some people are even wondering, inside of our cells we have mitochondria, which could that have been, that can't live out on its own, but is it considered living? I don't know. It depends on what you consider. All of these , viruses contain either DNA or rna.
DNA is what makes us, us. It's like your, your blueprints and RNA is kind of the same thing. And they also have proteins. However, they can't make their own proteins. So again, not free living. They have to use a living cell in order to do what they need to do. They also can't generate their own [00:09:00] energy.
They steal it from the cell that they're in.
Katy: mine. Just
Laura: I need this
Katy: me Yeah
Laura: I mean, man, they figured it out. They don't need to do it themselves and not when they can make somebody else do it for them.
Katy: I mean,
It going on.
Laura: on. Yeah. Most have a capsid or what's kind of like a shell that protects the DNA and RNA and provides attachment points. So most of us are familiar at this point with what C looks like, the little symbol for it's everywhere. It's a little ball covered in spikes and so sometimes those capsids that shell has things to attach with.
And it usually also has the proteins that can use to penetrate or inject the cell so the, you can get in it or stick its stuff in there. And and as Katy will tell you, they come in several shapes and many sizes.
Katy: Just,
Laura: um,
Katy: write these things and [00:10:00] then just keep moving. Like it doesn't,
Laura: Yeah. Yeah. Well, because I think, I think I, well I write bullet points and so they're very abbreviated. So then my mouth just says I just say it
Katy: This is why we're friends folks. This is why we're friends.
Laura: I'm just a constant source of entertainment. Um, so that's what a virus is. Real quick, what do they do? And then Katy will jump in. What do they do?
Well, some might immediately cause cell death, which I just like that term. Cell death. It's, it sounds really intense . but not because it's, And more than just death, cell death.
Katy: Yeah. maybe. Yeah. Cuz it doesn't
Laura: cell death.
Katy: Yeah, it doesn't, Cause it's not, it's not, it doesn't kill the host. Nothing. No. It's immediate cell death.
Laura: cell death.
Katy: cell death.
Laura: So it can do that or they can lie dormant. Sometimes their DNA or [00:11:00] RNA is integrated into the host dna, which I'm gonna talk about this later too. But sometimes we like intermingle our DNA with viruses and they hide their DNA in ours. And all of a sudden, some stimulus will happen, like UV light, and then bam, they become Yeah.
Or stress stress
Katy: was gonna say
Laura: lot of triggers. Yeah. Some can cause cancer which I actually also don't think I knew, but I mean, if I thought about it, I guess so, because they, they, a lot of the human papillomavirus, Yeah. Herpes that can lead to cancer and things. Most and most viruses don't cause disease.
But some do. And those diseases can either be acute, meaning like just short lived or chronic and last forever. So some are the gifts that keep on giving and some will just be here and gone. And most of them won't even make you sick, which I think is pretty cool.[00:12:00]
Katy: I guess I, I don't know if I would still want a virus
Laura: No, you're right. Okay. Yeah, yeah, yeah, yeah. So maybe not cool, but
Katy: Hey. I can
Laura: like, eyelash mites you're like, eh,
Katy: no, I
Laura: don't really,
but so that is what a virus is and that's what they do.
Katy: Okay, so I'm gonna go over then the three. Okay. So here we go. I'm gonna talk about the
Laura: This is just like my taxonomic crisis of
Katy: It just, they really attempt to make it simple, but it's not. So to keep it simple for our nature novices listeners we're gonna, I'm gonna first give you three different types and we broke it down by morphology, and then I'm gonna give you the scientific way of how they break it down.
So morphology, like I said, we're gonna break it down by the three different types of morphology, is just the foremost shape of the living organism. That's really all it is, and their relationship between the structures. The three basic ones are heli, helic, [00:13:00] iso, and complex viruses. Because most viruses probably evolve from different ancestors.
The systematic methods that scientists have used to classify the different types of viruses are, well, the, how can I say this? The classic way that we use to classify plants and animals. Cannot work for viruses. Yeah. Cuz it's just, yeah. It's just, it just can't work that way.
Laura: I'm sure it's constantly changing
Katy: Oh it is. Yeah.
And that just gives us like a ton of different ways to categorize these stupid things. Of course cuz they can't make it can't, nothing in science can be ever be
Laura: Definitely not when it comes to classification. Yeah,
Katy: Yeah. No, but at least that gives us a lot of content cuz everything's always changing.
Laura: very, true.
Katy: so the helical is, the shape of the virus is a spiral shape that curves cylindrically around an axis.
Like a
Laura: I just like a spring.
Katy: Yeah.[00:14:00] In the case of the Heyl virus, the viral nucleic acid coils into the helical shape and the capsid, what Laura was talking about before, proteins wind around the inside or outside of the nucleic acid, forming along tube or rod like structure. And so yeah, it'll go up, but it's a tube.
So like Laura said, spring,
Laura: a tube. Oh and nucle acids. That's the DNA rna.
Katy: Yes, yes, yes. For those you don't know helico viruses can be enveloped or naked. And so what's an envelope? A viral , you
Laura: those
Katy: those naked viruses. But a virus envelope is just the outermost layer of many types of viruses.
It protects the genetic material and their life cycle when traveling between host. Not all viruses, like I said, have envelopes. Some are in fact naked.
Laura: cheeses.
Nay.
Katy: one of these viruses that has the envelope is the tobacco mosaic virus, which is a naked, [00:15:00] or sorry, sorry, this one is a naked helical virus. But it, it only, you were talking before about how some viruses only affect certain things.
This is one that it can affect other plants, but it is very rare. It pretty much goes after tobacco plants and it makes their leaves look like a mosaic. . Well, not ooh, for the tobacco plant , but most plant vi, most plant viruses are helical. And it is very uncommon that a helical plant virus is enveloped in contrast, all helical.
Naked plank. Yeah. In contrast, all helical animal viruses are enveloped. For example let's see here. Some are like the influenza virus, measles virus, mumps, rabies, and Ebola, which it does make sense why a plant wouldn't need an envelope and animals would, cuz it's like a, it is a way harsher environment.
You figure
Laura: Yeah, The whole and animal cells, everything. Trying to kill it.
Katy: Yeah. Everything's trying to kill it and [00:16:00] attack it. And the plant's just welcome. Come on in.
Laura: or cuz do plants have immune immune systems?
Katy: not in the same way
Laura: Not in the same way. Yeah, yeah, yeah.
Katy: So, so anyway, yeah. So animals are viruses that are attacking animals. They do have to be a lot tougher to be able to survive. So being helical, there are several perceived advantages to forming that particular shape.
First, only one type of capsid protein is required. Because only one is required, that subunit is repeated over and over and over again to form the capsid. And this structure is so simple, it means it doesn't really require a whole lot of energy to assemble. Then a capsid made of a composed, made up of multiple proteins.
So super easy. In addition to the simplicity, having only one nucleic capsid protein means that only one gene is required instead of several. Again, it reduces the, the length of it and the nucleic acid that's required to make it. So, doesn't really need a whole lot because the [00:17:00] hele structure can continue and definitely there is also no constraints on how much nucleic acid can be packaged into the viron.
So the cap length will be the size of the coiled nucleic acid. So it's so simple. It's easy to do. However long it needs to be, can be that long. All right.
Laura: They just do not, they're just like whatever.
Katy: yeah, just, I'm just gonna keep building. Okay. Thank you. Bye. The second morphology or shape of viruses I wanna talk about is isometric viruses.
These are by far the most prevalent viruses out there, iso.
Laura: that it's not the simplest ones that are the most prevalent. You think like,
Katy: So this one is simple, but for a very different reason. So isometric viruses are roughly sort of spherical. And it's in the sphere that the genome of the virus lives. Although for simplicity's sake, a lot of people say that there's fearful. They're really, and this is gonna be the nerdiest thing that I've ever said, but the only reason why I know about this is because of Laura freaking, But I, [00:18:00] I, I go, Sahi means 20 sides.
So it's like a 20 sided die
Laura: That's amazing.
Katy: So that's what these viruses are. So a long time ago, whenever we first, Yeah, whenever we started looking at them, they're like, Oh, they're, it's a sphere, so they're spherical. And then whenever we got new technology can really zoom in and see 'em,
Laura: you could see facets.
Katy: They're like, No, it is not actually. And I don't wanna go into. Too much of the detail, but there are aspects of the isometric viruses that divide them into further, which are called twofold, threefold, or fivefold access groups. But, and it, it all has to do with if you take a pencil and stick it down through one of the points, how it'll come out like another point.
And depending on where those, like each of those little flat sides
Laura: Yeah.
Katy: is like another like piece to the puzzle. So it needs all those 20 sides. for the complexity of it, but it's also each, like its own individual thing. It, it's fascinating, [00:19:00] but I'm not gonna go into that here cuz it, it does get into some really deep sides, but isometric viruses, if you wanna look into it further, it is actually really, really cool.
So why does this is the iso, he, whatever it is, 20 side structure appear so often? Research has shown that proteins which form the 20 side cemetery require lesser amounts of energy compared to other structures, even less than the helical. And so this structure is evolutionary favored. It's because all it is like, whereas the helico has to
build like the whole capsule and then helico it up, make it a spring.
Technically this one, it's my understanding that it's like each one of those sides, it just has to replicate a side. And it has to replicate a side. And so they're like, that's what I'm saying, like they're individual, but they're also all together. So whenever you're making it quote unquote, you're only really making a side.
And then like your job is, like their job is done and then, and then another [00:20:00] group, quote unquote, comes in and makes that other side. Then they're, kind of done. I don't know how else really to explain it. But anyway, so many of the viruses that infect animals are this isometric, including HPV, rhinovirus, Hepatitis B, and the herpes viruses.
Unlike helical, iso hel viruses can be naked or envelope as well. Did I say unlike helical or like Like helical. They can both be naked or envelope. The third type is a complex virus, and these viruses have just pretty much gone rogue.
Laura: Yeah I just like how it's like, Okay, this shape, this shape and all the other ones,
Katy: Just, yeah. Whatever else these guys wanna do, let's just lump them all together because I think they're
Laura: them complex.
Katy: Yeah. Calm complex because none of it makes sense. So there architecture is not strictly conform to either the helico or iso hel shape PX viruses getting the viruses. And many other bacterial [00:21:00] phages are examples of viruses with complex structures. PX viruses, including the viruses that call cause smallpox or cowpox are large oval or brick shaped particles.
And something I was reading something about, like they also have dumbbell shape things in 'em too. Like they're just like multi, multi shapes, different shapes, all combined. The Gemini viruses also exhibit complex structure as their name suggests. These plant infecting viruses are composed of two, two of the isometric heads joined. So, all right. So while we can talk about their morphology as a simple way to divide up the virus, is there is also, of course, a more official approach since there are so many different characteristics. Go ahead.
Laura: Oh, sorry, I was just gonna jump in. What's the, And it, are you the the not
Katy: There is the PX viruses and then the county
Laura: Yeah Yeah. Well, I looked up a picture. I see what you're saying about the [00:22:00] Fox one, but what's, what's it's before a what's the thing that leads to aids?
hiv, right hIV is one of the bacteria phases. Is that what that one is? Right. The like.
Katy: no,
Laura: Cause there's are those, what are those? Also the ones that are considered complex with it look a little dart
Are they retro?
Katy: saying that it's complex, but I don't know if they mean structurally or if they're just saying it is complex, you know? Well, we'll, we'll keep looking for it though. Cause it looks like it's saying the composed of two strands of RNA is packaged inside a distinctive, cone shaped capsid, which protects the rna.
Yeah. So it would have to if it's cone shaped.
Laura: Yeah.
Katy: Yeah. So it had to be, Yeah, it would have to be
Laura: yeah, yeah. I can see it, but yeah. Where does the little, like where does it have its little stall? What's the,
Katy: It doesn't have to, Not all of 'em do.[00:23:00]
Laura: No. Yeah, so they've got these, like they can be all these different shapes, but, but is it only complex that can have them?
Katy: I don't think so.
Laura: Okay, I was just
Katy: I I, I can't imagine the helical having them, but I definitely know the isometric viruses. Definitely have
Laura: Yeah. Okay. Sorry.
Sorry I just would I cuz I know that was a it's a, that the phage shape is so weird, but I wasn't sure if that was considered a, a grouping
Katy: No, no, no, no. Cuz they,
Laura: separate thing.
Katy: No, no, no. Yeah, because it can, bacteria phage is, the phage part itself can be on like a different head. So it can either be in complex, I don't, I don't remember ever seeing one that was on helical that would look kind of weird. But isometric for sure.
Laura: Gotcha.
Katy: Okay. So besides morphology then the other way that we can divide these up is like we were talking about [00:24:00] earlier, which is the more of like the classification taxonomy that you would see normally.
And so this is like the more official way of how scientists narrow it down.
they group them. There are seven different groups. Well, let me hear, let me first start by saying this. There was one classification system that was developed in the 1970s by a man named David Baltimore. He was a Nobel laureate.
So I mean, I guess he knows what he is talking about . So because he developed it, they named it after him. I mean, fair enough. The Baltimore classification system categorizes viruses based on the type of nucleic acid genome and replication strategy of the virus. So the Baltimore classification system has seven different classes to divide viruses into.
There are a variety of ways by which the viruses can be classified, however, including the virus on size, capsid structure type of nucleic acid, physical properties, which kind of talked about [00:25:00] the host species or the disease that it's caused. And because everything else, that scientific.
Classification does is so freaking difficult. They decided to form in, I think it was the mid sixties, the International Committee on Taxonomy of Viruses, the ictv, which is basically probably a group of just, I don't know, people who really get excited about virus shapes. Yeah. Just get really excited.
But but they help divide it. And by watching how these are grouping, a lot of it we can see small changes over time within the viruses and things like covid, how you keep here and all the different, all the different strands that are coming out and how it's evolving. This is how we're able to keep track of it, because they can see from one jump to the next, to the next, to the next, all in one grouping.
And so that's pretty much the Baltimore classification. So you have the morphology that we talked about, the three main groups. There are plenty more that you can break it down into, but that keeps it [00:26:00] simple. And then the Baltimore classification, which is like the. Actual way to classify things.
Laura: Gotcha. So we talked about, what is a virus, what they do, how you can categorize them. Once a virus infects someone. It starts to go through what is called the cycle of infection. This cycle is not true for all viruses, but it is true for most of them. So the first thing that happens is what's called ad absorption.
Where a parental virus or vion attaches to a cell in some way, whether it, you know it just, it attaches. Then it either penetrates or injects depending on the type of virus. Then the nucleic acids, which is the dna rna, get free. It attaches, it gets inside, it unravels it's DNA or rna, and starts doing what it needs to do, which is translation and transcribe transcription.
So [00:27:00] it's translating its dna, it's transcribing it, meaning it's building new stuff. Then it starts replicating itself. Then it puts all those pieces together in assembly and then boom, release. So the, that's the cycle of infection. Like I said, not all of them do that, but most of them do. So in order to prevent or treat viruses, you have to disrupt the cycle of infection somewhere.
Easiest thing to do is just to prevent them from ever happening.
Katy: just to stop it all together, you
Laura: don't even let the cycle start . And that's just through things like hygiene whether it's your own hygiene or clean water and things like that, just cleanliness. Get rid of those viruses.
Katy: Covid has been horrible. My grandfather died from Covid. But I will say I have never loved flying more than I did during Covid because I was prior to Covid, one of those people that sit down and wipe everything down because airports are so disgusting. And it finally [00:28:00] took Covid for airports and airlines to be like, Hey, we should maybe be a little bit cleaner and and they finally did it.
So, yeah, it doesn't take much. I mean, it does not take much.
Laura: Just a few steps, just a few steps to keep hygiene. Then prevention also is vaccines. Of course not all viruses, not, we haven't developed vaccines for all of them, but we've developed vaccines for a lot of them. And there could be a whole episode on just vaccinations and how they work and all that stuff, because there's a lot of misconceptions about them all.
But in general, a vaccine helps to prevent and or mitigate the effects of a virus. So it doesn't mean that you might never get the thing, it
Katy: makes it a little bit easier for you to fight it.
Laura: yes. And then
Katy: of, I gotta get my covid, that booster
Laura: I just got mine.
Katy: I need to get my other one.
Laura: But it. It can lead to someday the elimination of the [00:29:00] virus. So there are some, there are some viruses that because so many people were vaccinated and it, it prevented it from mutating and it eventually ran its course kind of thing.
Right.
Polio smallpox, couple of other things like that.
Katy: You know, science, doing it's science thing,
Laura: And then and
Katy: shocking as it is.
Laura: if you do get a virus, antibiotics aren't gonna do it because antibiotics are against bacteria. So the only thing that can be done once you have it, other than just ride that sucker out is that they have started to develop more antiviral. And this, that is just preventing one of these steps.
So it is, it's disrupting the cycle. It's disrupting replication or it's disrupting assembly or something like that. They've developed, where at some point it's not letting the cycle continue on. So it's not, getting rid of what's already in you, it's preventing it from, from becoming more and more and more.
[00:30:00] So that's that's virus isn't a nutshell.
Katy: Okay. Do we wanna talk? Do you wanna go first or you want me to go first for our one that we've chosen?
Laura: Let, I think, actually let me go first if you don't mind, because I think mine will set the stage for you. So we said that viruses have a huge impact on living organisms and their evolution. Just cuz they're not alive doesn't mean that they're not changing the planet.
Katy: And that needs to be a t-shirt quote. Just because you're not alive does not mean you're not changing the world.
Laura: Yeah,
Katy: just have, just have a tiny little bacteria. Like a,
Laura: Oh yeah. Bacteria. Yeah. Yeah. Not a bacteria. Cuz those are alive.
Katy: No, no. The backage is like a little, like a really cart unified one that just says like around it and like really bubbly font. Just because you're not live doesn't mean you're not changing the world.
Laura: Changing the world.
Katy: That would be amazing.
Laura: imagine it like the little DNA guy from Jurassic Park.
Katy: yeah.
Laura: kind of cartoony.
Katy: Right.
Laura: [00:31:00] So viruses can do that in a couple of ways. Change the world and effect evolution. The, the most straightforward one is just, I, they just kill off population. It's a population, like the survival of the fittest.
Only certain traits are making it through. But that's the, that's the easy way. They're affecting evolution. I wanna talk about the way that they have changed evolution with their own dna. So what I'm gonna talk about, it's not one specific virus, it's a group of viruses. Hold endogenous, retroviruses
or particular in particular human endogenous retroviruses.
All right. Kids. Settle down and listen to my story.
Cuz it's such a big word. So viruses likely came from cells. Okay. Cells did not evolve from viruses. Viruses probably evolve from cells and are just their rogue, their [00:32:00] rogue nucleic acids. Some, at some point they just
Katy: Decided to do their own thing.
Laura: Yeah.
bone
Katy: being the first one? I don't need to be here anymore. I don't need to do this anymore.
Laura: This is way too much work. I am just gonna go find someone else to do this for
Katy: Yeah.
Laura: So once they developed, they started infecting things. And over the last 100 million years, humans and all of our ancestors, so all of the other primate lineage and, and probably even before then have been infected with countless viruses.
And those viruses have actually left what was kind of like a scar in our dna. So scientists have discovered that human DNA is actually about 8% viral dna.
Katy: Of course we are. We're just a walking virus. Yeah, we're just,
Laura: I'm having
Katy: go, Laura,
Laura: Have we not talked about this again? [00:33:00] Haven't, didn't we talk about this before? Oh, that we're walking.
We said before that we were all walking bacteria.
Katy: Yeah. And now we're just,
Laura: we're walking
Katy: Yeah.
For Yeah. Forget any, We're not human. We're just bacteria and viruses running around
Laura: 8% at the very least. And an 8% means about 22 families of viral like gene
Katy: Jean. Yeah
Laura: are in the human genome.
Katy: of course.
Laura: How do they know that? What did it do? Well, some of the viruses left behind their dna, so if you remember what I said, sometimes our DNA can get like intermingled and right, because the whole point of this virus is it sticking its own DNA in ours so that our cell is like, Okay, I'm re like, I'm just
imagining I I always imagine the cell is like a tiny little, very much like Osmosis Jones.
It's everything's alive in it. Okay? So somebody is just doing their job head down, just typing out
Katy: Yeah. Just, yeah. Needs
Laura: whatever they're. Just gotta,
Katy: [00:34:00] o'clock and then I can go home.
Laura: Yeah. So they're just making whatever the DNA says to make, whether it's, they don't recognize it. It's not our own stuff, it's
Katy: doing their job. Yeah. It's doing its job
Laura: it.
Well, sometimes then the virus is supposed to pull it stuff back out. But it doesn't always do that. Sometimes it leaves stuff in. Sometimes it takes more than it should sometimes. There's just different things that can happen in general. Sometimes we then intermingle with each other. Hence the kind of like the scar that we is left behind.
And some of those d some of that DNA found its way into sperm and egg cells and became part, and can become part of a permanent species's genome like it did for us. And they were like, Okay, well how do we know that this is, Like viral DNA and not just some weird fluky, weird dna. Scientists of course went in and they like switched something on in that segment and all of a [00:35:00] sudden, Yeah.
All of a sudden it started like producing live viruses of some extinct virus
that you
Katy: See, Okay. We have talked about this before, guys.
Laura: Do not medal with stuff like that.
Katy: Yeah. It's like whatever they find found the stuff in the, the an the ice in the an, the Antarctic. Just, just stop. Just don't do that. We should know better by now.
Laura: Even if you are like, I don't care to prove a point or not. Man,
Katy: don't
Laura: terrifying. There was nothing like,
Katy: Causes one, one slip or one sneeze, and then suddenly that is broken and then , the whole world has it.
Laura: So they did, they were like, okay, yes, this is extinct viral dna. I don't know how they turned it off again, but whatever.
Katy: right? They're like, I dunno how to do it either.
Laura: The it in a volcano,
Katy: yeah ,
Laura: so
Katy: I just picture like this tiny little scientist with a Petri dish out in front of, I'm like up to the top of volcano and just chucks it in there. Runs back down. Who close? Guys. That was close.[00:36:00]
Laura: So that is, that's how it's gotten into our dna. How does that affect evolution? Well, because everything we are is dna. One of the things
Katy: I really thought we were gonna get it through an episode without having a mental crisis here.
Laura: Yeah. These deep science ones are always a So they compared this whole viral DNA shenanigans probably led to the differentiation of species. So they compared human and chimp dna and of course were, super duper similar. We have the same scars. I'm doing air quotes here in our DNA as chimpanzees do
most of them.
Okay, So
they're called insertion points. These insertion points where the viral DNA shows up. so
they're, there are 10 million possible insertion points within dna. Okay?
Katy: I feel [00:37:00] like is a little excessive, but continue
Laura: there's just a lot of it.
So the fact that we share something so many points with chimpanzees, the chances of that being coincidence are one in 5.8, eight times 10 to the 1418th power
Katy: That's insane.
Laura: That's
Katy: That number shouldn't even exist.
Laura: Yeah it's never, it couldn't possibly be a coincidence. Therefore it shows a common ancestor in evolution. So this is the whole, like you, cuz before, before we believed in like the diverging thing, people believed, okay, like chimps were from the beginning, humans were from the beginning.
Like this shows at some point we were belonged together. And so this dna, all of this changing DNA from all these viruses could have led to that happening. And then one last honorable mention about how these human endogenous retrovirus have [00:38:00] changed us, they've actually found that there's this protein called sy site, which is produced by viruses and is found in the human placenta.
And they're pretty sure.
The at some point some crazy mammal ancestor got infected with something. The DNA got left behind and then they started having placenta's like the only
Katy: know what? I felt like becoming today a placenta
Laura: a mammal.
Like I just so like we can, the fact that we can even have babies via placenta probably is something from a virus that we got.
Katy: This is just, Yeah. I, again, this is, we just have like mites in our eyebrows, bacteria all over us, and now we're just walking viruses. It's fine. Guys. We're, we're not humans. We're just here for the viruses. It's fine.
Laura: All right, What's your buyers?
Katy: Good grief. So I'm gonna take a little bit of a different spin on [00:39:00] it and I'm gonna talk about avian flu.
And Laura, you did mention
Laura: I'm gonna talk about avian flu,
Katy: Yeah. Trying to make a positive here.
Laura: up spice it up a little.
Katy: millions of birds are dying folks. So just as Laura mentioned about how sometimes it can just be parts of populations just killing over. Let me tell you about the avian flu. So the avian flu is a helical virus.
It's often spread by contact between infected typically wild birds first and healthy birds, though it can be spread indirectly through contaminated equipment. Again, keep your crop clean. And we said typically wild birds. Only because like your domestic, for the most part, your domestic birds aren't gonna be like, I don't know, traveling.
And so the wild birds migrate, and so that. Leaves of wake of flu in its path.
Laura: wake of flu.
Katy: Yeah. Right. So the virus is found in secretions from the nostrils, mouth, eyes [00:40:00] of infected birds as well as their droppings. If you were just like getting it from a goose eye booger, like that probably wouldn't be a big of a deal.
But because they poop everywhere, everywhere every what, five minutes or so, it's just a ridiculous amount. All right. So symptoms for the bird of avian flu depend of course on the bird itself. But it could be anything from purple like a chicken, cuz I know a lot of our chickens are being wiped out by avian flu right now here in the us.
But like their waters, combs, legs can turn purple. They can have really bad diarrhea, nasal discharge, soft shell or misshape in eggs. A drastic decrease in egg production. Coughing and sneezing, lack of coordination, swelling of the head eyelids, wattles, combs for as far as chickens go, lack of energy and appetite.
Pinpoint hemorrhages in the feet and legs. It could mess up with their feathers. And the major warning sign to watch out for is they will just die. Birds, [00:41:00] typically they hide their symptoms until death. They, they do not. And I know everybody says it's like for an evolution purpose, to survive.
So they don't put peer week in the wild and I really don't know if it's that or they're just like not smart enough to know that they're sick. Cuz I've met, you know, some pretty. Birds. But a lot of 'em will just, they could be like, have sniffles and you're never gonna know it because they're going to hide it, and then that's why they just end up dying.
And when I say dying, it can wipe out a whole, poultry chicken coop. Yeah. And a couple days, like all gone. So to prevent spreading when you're around birds you have to disinfect shoes, clothes, hands, egg trays, anything like if you're collecting eggs for chickens any sort of cleaning materials, anything.
If you're driving through an area with the birds, I mean, just, you just have to really be diligent on
Laura: I know that they'll, they order like recently, I mean, if one bird ends up getting it, they have to kill all the [00:42:00] birds.
Katy: Yeah. Yep. Because it's gonna, it's gonna go through it and then, Yeah. Because it's, it's not only going to, and the, the reason for the calling. . It's not only because it's gonna, it's gonna wipe 'em out probably anyway. But if those birds droppings, if one wild bird not in a healthy wild bird, even remotely gets close to it, boom.
That wild bird catches it and then off it goes again.
Laura: Yeah.
Katy: Yep. So the avian the avian origin, influenza viruses that you're, I'm gonna, you're gonna hear me refer here and there about h something and something, and to explain that, so all of the bird flus that we're talking about, there's Influenza A, B, C, I think there was d I don't remember.
But all the ones that we're talking about are influenza A and they have the H is the Hema glutenin or H proteins. And there are 16 different ones. And then the neurite, [00:43:00] dsis, ah or N proteins. And there are nine. So as many different combinations of H and N proteins that are possible. So there's 16 different Hs and nine different Ns, and then however many different combinations, that's how what you get.
All right. So let's cover a little bit about the history of the avian flu, so we can see where this is going. And this is gonna just be real quick here. It was first recorded in Northern Italy in 1878 by a veterinarian, Edoardo Ed. It's E D O A R D O, Portacio. Hmm, go for it. He started to notice some sort of contagious respiratory disease that was spreading among poultry and it just like high fatality.
rate. And he's a vet, he's going around, he's seen all this stuff, which not that I think about it. He was probably the one spreading it. . But he didn't even know. He didn't even know. So for almost [00:44:00] 100 years though, they thought that what this guy was seeing was bird cholera and Yeah. Right. But it wasn't until 1981, it was officially renamed and proven to be the highly pathogenic avian influenza or H P A I, which there is an important difference between highly pathogenic AV influenza, H P A I.
And then, because on the flip side, there's L P A I, which is low, so that you have high and
Laura: Oh, okay. Okay.
Katy: HPAI continued to spread globally through the 1920s with sporadic outbreaks occurring. Several of these outbreaks occurred in the US from 1959 to 1995, and, but they were sporadic, like you'd hear about it in the news or whatever.
Go away, hear about it. You know, not, not anything crazy. Emergence of the avian flew across the world was reported on 15 separate occasions. All infections were caused by the influenza A virus, but the subtypes vary between H five [00:45:00] and the H seven groups. In 1996, a new strain of avian flu subtype, H five N one, was introduced to poultry via migratory water fowl in the Guangdong Provence of China.
This resulted in a mortality of greater than 40% of the aquatic birds,
Laura: Whoa.
Katy: which, which is so , so many birds. And that was kind of, So many dead birds. And so this was sort of like the first one that we had recorded. That was in 96. That was just like, Whoa, this is a ton of birds. It just died. Subsequent events between H P A I and then the L P A I led to a new H P I.
Cause you know, Laura was talking about how they intermingle, like they, we humans, I'll get into this in a second, like we can get these, but this is one of the ones that, because there's so many different combinations, it rapidly evolves and changes and morphs and adapts. So it led, this all led to a new H P I [00:46:00] strain that 90 19 97 in Hong Kong resulted in the cull of the entire poultry population.
Laura: Oh
Katy: they just like, Why? Yeah. So they, Hong Kong was just like, You know what, we're gonna stop this right here, Boom, kill 'em all. And so wham whole poultry population gone. And during this 18 human infections and six human deaths were also seen in Hong Kong. So this is also sort of like the first time that we, we had seen reported deaths before, but now it's okay, this isn't like one flute, this isn't like just a chicken farmer.
This is like, we're starting to see some numbers here. And they didn't think that it was really possible before 97. So after the outbreak of the H P A I and Hong Kong evidence of H P A I seemed to taper off from 1997 until 2003, when two humans were diagnosed with H five N one, which is when we frequently hear, heard about, after returning from China from 2003 to 2018, human cases were [00:47:00] reported from 16 countries resulting in hundreds of deaths.
Now, from people
Laura: my gosh
Katy: H five, H five N one from birds. Cause again, it's adapted. The virus has figured it out. Okay. This isn't killing off my host. This isn't, this
Laura: Well
Katy: is, like what,
Laura: And plus, plus when things jump from species to species, the new species has zero capability of dealing with it, cuz we never have
Katy: Yep. Ha does know. The pandemic risk associated with H P A I is insanely high. The combination of rapid mutations and the H and the N strains and the increased risk of H P I spill over from poultry to humans is caused for significant concern. And I've seen this on like several different websites that people are like, Listen, we should probably be looking into avian flu a little bit more than what we are.
This could be like the next pandemic level. H five N one h. P a I was replaced then [00:48:00] by the H five N six and H five N eight subtypes from 2014 to 2020. Then in 2 20, 21, H five N one emerged again and seemed to be, just came back. And what decided that, you know what, I've left for a little bit, but I'm here to stay.
And since early 21, H five N one has been the one that has been responsible for the outbreaks, that has effectively wiped out any other, like H five H P I viruses. Like for whatever reason, H five N one is Nope, I'm, this is my area now. And so while the reason isn't entirely sure it is believe that the explosion of cases is due to the introduce and spread of the virus by migratory birds, which I know, like whenever Laura and I were in the zoos and we had.
Avian flu here in the, in the states really bad. Like we had to take all sorts of extra precautions for birds within zoos[00:49:00] during migratory seasons because you get one again, one infected bird dropping and then it can infect your bird.
Laura: yeah, yeah. This past, it hit the East coast here a couple months ago
Katy: Yep. They said in the US alone, the current outbreak for this year of the H five N one has led to the death of over 37 million poultry.
Laura: Yeah. It hit the east coast like Jersey and eastern Maryland a little bit, but New Jersey a lot. And a lot of us pulled our birds inside, like we didn't let our owl out for a while and like
Katy: Yeah. Cuz it doesn't take, it doesn't really take
Laura: I knew it was really going, it was really an issue because I have to get frozen chicks
for the owl to eat
Katy: Uhhuh
Laura: astronomical price increase like three times as expensive as normal
because there were like, had to cu so many chickens.
Katy: Yeah. Dang. Well, so what does this all mean for the future of birds? So let's just think about it. We've talked about birds. [00:50:00] Yeah. And humans. So we've talked about birds quite often in a lot of different episodes. So first off, what does this mean? If my six year old doesn't get his chicken nuggets, all hell's gonna break loose.
First of all,
Laura: I for most kids, I think
Katy: And I really think that the only thing that would be worse than no chicken nuggets for him would be there's no more ketchup. That might be the only other thing that would tip it over. So food. But like food, if we don't have chicken and poultry, you ask how. Like chicken. Americans
so much chicken in so many different forms.
So it would be a complete devastation to the poultry industry, which is, yes there are huge, big brand name companies, but there are a lot of farmers and individuals who rely on poultry farming or even like local little urban farms that, have chickens and, and things. And so that is a, a significant loss of money for families.
Wild bird deaths though. Think of all the different pollinators that we have out there of different bird species [00:51:00] and you, they start wiping out and they start getting lower in numbers. There's tons of. Plants, trees and stuff that just, Nope, we're not gonna have 'em anymore because we don't.
Birds play a huge role in pollination of 'em rodent control. Imagine all the mice that we have. We don't have any birds of prey left. And again, the more the few flu virus mutates, the easier it has been spreading to humans. Yeah. And it, and it has been jumping and the more, yeah, now it's the H five N one that's been jumping, but as it continues to jump and evolve, it's just gonna get worse and worse.
And so we're just gonna start seeing it in humans more and more. And so, yeah, so they're saying that this is the one to watch out for if we're gonna have another pandemic. Like they're saying that it's the avian flu is gonna be the one that's gonna hit us,
Laura: Oh on that wonderful note. Geez.
Katy: listen. It is fascinating, but it's like one of those like, Hey, yeah, you should probably watch, watch the news [00:52:00] if you hear avian flu. Don't just be like, Nah, it's the birds. No, it's humans too.
Laura: Yeah. Well, I guess it's too, it's at least a good incentive for different poultry practices. Like maybe we shouldn't have them all packed in together so tight and maybe, you know what I mean? Like some
Katy: Well, not only that though, but it's like even even these small farmers that let their chickens free range, they're the ones that are probably gonna get it, faster just because they're out and about with, wild birds and stuff. So it's like, it's just like a detrimental thing that it's just gonna keep wiping, wiping up populations until, until, like you said, like with, with yours, with the VI or the let's say the antivirals and stuff you could do.
There has, there's that break that split, but for these guys, it's just there just needs to be a point where we gotta stop it and that's why they keep cull populations of birds and hoping that one of those will be the split that it needs, but doesn't seem like it so far. Right. Second pandemic.
Woohoo. We're millennials, we're [00:53:00] numb to any kind of world chaos at this point anyway, so it's fine.
Laura: Yeah. Well,
Katy: to hear folks.
Laura: and just I guess to end it so that people aren't just Oh my freaking gosh. I mean, it's fall, we're all getting sick, but just remember. Most well wash your, wash your freaking hands, cover your mouth all the things and, but that most viruses don't even cause disease.
Katy: Yeah. Most of 'em don't, It's just we gotta keep ourselves clean from the ones that
Laura: those few.
Yeah.
Katy: just, just those few that happen to be very bad. Well, that note guys. viruses. All right go ahead and check us out on Patreon and on check with us on Twitter and let us know. If you guys, I guess if you guys have any episode ideas cause we're gonna be coming up on the end of this one and Kim's gonna have a break.
I don't know if Kim has any ideas for the season break yet though. But if you guys have any ideas for Kim to go over this time set, make [00:54:00] sure you send 'em our way. Until then, we will talk to you guys next week.
Laura: next. Bye. E.