Green Beard Genes

Mercantile in Manhattan. Stuff You missed in History class has a show right before us, so you can really double down, learn more and buy your tickets today at New York Comic Con dot com slash NYCC hyphen presents Welcome to Stuff to Blow Your Mind from How Stuffworks dot com. Hey, are you welcome to Stuff to Blow Your Mind? My name is Robert Lamb and I'm Joe McCormick and Robert

I got a question. How often do you have this experience of finding out one subtle way that somebody is like you, and it's suddenly changing your whole attitude toward them. So you're talking to somebody new you haven't met before.

You know, you're getting to know somebody who's been an acquaintance and you find out that they really like one movie that you like, or they really or they've traveled to one place you've traveled to, or something like this, and suddenly your brain just unlocks and you say, oh, okay, we're cool now. Yeah, I encountered this a lot. You know, they'll be I tend to be a little you know,

distrusting of new people and uh. And then sometimes you know, you get to talk to them a little bit, or you check out their social media activity or something in your lies. Hey, they they really like this film, or they they really like this artist that not many of us are into, or they're into this h this other a kind of niche thing that I love and there and then you you you sort of give them the

benefit of a doubt based on that information. You're like, well, they're they're probably pretty good, they're probably pretty cool, Like, babe, I should talk to them a little bit more. What else are they into that I like? But why why is that? I mean, why is it that just using like a shared favorite movie for example, Like what basis do you have for thinking that somebody who likes the

same movie you like is a good person. Well, it falls apart under the scrutiny of other things, because, for instance, um, I'll use Tool as an example. Tool is one of my my my favorite bands and Uh and their band I loved in in high school and I've never I've never stopped loving. There's been a lot of bands that a lot of musical styles that have sort of come and gone that I'll rediscover and and or that I'll hate for a little home. But but but I've always liked Tool.

So what you're saying is the best rubric for discovering whether a person is good or not is do they like Tool? Yes and no. So, for instance, here at work, Nathan our our our social media guru, uh, shortly after he started, he saw that I had some some Tool memorabilia at my desk, and we instantly struck up conversation about it, and that was like our initial uh uh, you know, bonding moment, or the fact that we both

like this group. On the other hand, I've gone to enough Tool concerts to witness people that are also fans of Tool and sometimes interact with them where I end up getting a bit judge, and I think to myself, well, there's no there's no way that they are appreciating this music on the same level that I am. So it can kind of cut both ways. You can be very choosy about about how you feel regarding other people's appreciation

of your stuff. But ideally it would mean that if if someone else is into something that that the that you dig, then they're they're going to be into some of the same ideas, some of the same values, some of the same you know, aesthetic quality days what have you, that that there's going to be more than just this one thing that lines up between the two of you, right, But you're using that one little detail, that one tiny

thing is some kind of like totem. It's this one it's the signifier, this tiny flag flying above their head that you have decided, for whatever reason, is good enough evidence to open yourself up to this person and essentially give them a fair shake that you might not give to any other stranger. I've caught myself doing the same thing too, even though I realized it makes no sense. I mean, I think generally that you might be able to make some kind of case that in some cases

shared aesthetics or shared values. Uh, you know that if you like the same movie as somebody, it might embody some kinds of values or intellectual predispositions that you would find in common with other people who tend to like it. But a lot of times that's not the case. I don't know. I mean, I love Blade Runner, but there's probably a lot of people who love Blade Runner who are just absolute vampire. You saying they don't appreciate it

on the same level as you. Maybe that's it. I wonder if you don't appreciate it on the same level I do. I don't know. I've I've actually spoken about this a little bit, but my thoughts on Blade Run are mixed. But I do I do. I do love Blade Runner. So today we're gonna be talking about a hypothesis in genetics and genomics that is going to be a kind of weird analogy to the personality tests that we've just been discussing, and it's the concept of green

beard genes or the green beard effect. Now that the sad news is that this episode does not really deal with actual green beards. If you're looking for if you go, if you're coming into this expecting an episode and a weird genetic anomaly that makes people grow green beards, or say a famous pirate with a green beard. Um, you're gonna be disappointed on those counts. But the but the underlying science we're going to discuss here in the genetics

is pretty amazing and pretty fascinating. Now I wanted to come up with the backstory of the pirate green beard. I couldn't think of what it is. What it's like he's got algae in there or something. He just never cleans his beard. Yeah, you're just um, I'm guessing you probably have like really green teeth as well, you know, and just maybe he eats a lot of plant matter and it just kind of drolls down in his unwashed beard.

But you know, this does bring if there was if there was a pirate with a green beard and he met another pirate with a green beard, perhaps he would have this effect. He would say, look, there is another pirate who shares my esthetic qualities, perhaps my diet. Maybe we have more thoughts on hygiene. Yeah. So the name of the green beard hypothesis, which we will explain, comes to us from Richard Dawkins, based on an example he used to illustrate the concept in his nineteen seventy six

book The Selfish Gene. But the idea goes back to the influential English biologists of the twentieth century W. D. Hamilton's um And so the idea arises in the context

of a question about explaining how biology creates social behavior. Now, this is one of the biggest, most difficult questions in biology, right, So humans and other animals display these complex things like culture, like aesthetic preferences, taste, uh, social behavior, all these things that are complicated and have all these weird semi coded rules, and we know at some level must be at least

semi dictated by genetic predispositions. But it's hard to know what parts of culture and behavior are genetic and what parts are just happenstances that you know that that arise naturally and somewhat randomly. Well, we have all these levels of cognition and culture that are kind of an illusion and and and they're they're overriding the biology. But since we are the illusion, it's hard to it's it's often hard for us to really think about and in terms

of underlying biological properties. Yeah, so let's let's explore this question that this problem with explaining social behavior through biology. So we all know that species arise from the propagation of self replicating molecules like DNA, the fundamental units of heredity and DNA or genes. These are the parts of your DNA that do something that are inherited from your parents. And because genes make copies of themselves, we find some of the same genes spread out across many different organisms

in the same gene pool. Now, obviously, genes that cause an organism to die immediately at birth become less numerous and eventually disappear. Genes that help an organism survive and produce more offspring become more numerous in the gene pool. These are the fundamentals of evolution by natural selection. This is basic stuff. We we know it up to this point.

But here's a question. Why would an organism produced by this process, that arises out of evolution by natural selection ever displayed behaviors that we would call selfless or generous or altruistic, for example, things like sharing food with another

organism or defending another organism in a fight. Now, I do want to heavily qualify that by saying I think It's probably not hard to explain why humans in particular altruistic, because, after all, there appear to be a lot of ways in which our complex brains can generate motivation for behaviors that run contrary to our genetic fitness, and the simplest example one of thousands would be celibacy. Whether for religious reasons or philosophical reasons, or simply out of personal preference,

some people voluntarily choose never to have sexual relationships. This runs absolutely counter to our genetic programming. Another more common example would be the use of contraception. Many people who are sexually active still choose to have no children, or choose to have far fewer children than they technically could, for a variety of reasons. So obviously there are some ways in which the complex human brain has acquired the capacity to override the genes that programmed it well, I think.

One one example that comes to mind is say, for instance, my own son UH has adopted and so he is not my biological offspring, but he he fulfills all the needs and desires that that I had that I have as a human for for offspring, for a son, right, your genes don't care about him, but you do. Uh, it's it's there in your brain, it is there in

your personality. So if you were only wondering about humans, it might not be so hard to explain why we would share scarce resources with a stranger, or risk our own safety to intervene in somebody else's defense, or any number of other selfless acts. We're smart enough to recognize, maybe philosophical or religious reasons why we think we should to help other people and override those selfish instincts to

act on those reasons. Or if you look at it from another angle, maybe the more cynical person would say, well, our complex, language obsessed brains are highly vulnerable to memes that have the power to override the optimization of our genetic fitness. Either way, human mentality appears to be fairly unique on Earth, and it can account for behavior that you wouldn't expect to find in other animals. But altruism isn't only present in human beings with their religions and

moral philosophy and complex cognition. Altruism seems to be robustly observed in other animals, from like complex mammals all the way down to insects. Right, yeah, yeah, we have. We have a few I think very illustrative examples here to run through. Here's a crazy one. Vampire bats will regurgitate blood for other bats who were unable to find a meal, sacrificing their own immediate nutrition to keep another bat in

their community from starving. And this has been documented since it was discovered in the nineteen eighties by a biologist named Gerald Wilkinson. And that that's no small feat because these bats are sort of operating constantly near the edge of starvation. As we've talked about before. You know, if a vampire bat goes a few days without food, it's in a bad place. It can it can starve um.

And so sharing food like this is a significant sacrifice for the good of another uh not necessarily related bat. And you have to ask yourself, would your friends and coworkers be selfless enough to vomit up blood in your mouth if you've missed a meal. None of them have ever offered, And it makes me feel rather sour. But it's not even just the mammals, right, We see classic altruistic behaviors in in uh animals that are thought of

as less complex. Right, Oh yeah, I mean bees are a prime example of altruism, and I mean you social insects in general have pretty much perfected altruism in many respects. So worker bee works for the benefit of the queen's offspring while for going reproduction herself. Genetically speaking, she is not the genetic future the hive. The queen is, the

drones are, but the workers do all the work. In a weird way, you can almost think about the insects like this, being that the queen is the organism and the worker bees are like fingers or appendages of the major organism. Yeah, exactly, and it's just completely completely selfless if you look at it from the right angle. Yeah, but how about birds too, well, ravens who we've talked

about ravens a bit when we talked about bird intelligence. Uh, Ravens have been observed to call in additional ravens when they happen upon food, so like a mouse or something, which doesn't make any sense that they have it, but they have apparently have a special call that they use, so they raise the alarm and say, hey, other ravens that are not me or my children, come in here and get part of this mouse. Why would you do that?

It doesn't seem to make sense. But some ravens even return to their roost and recruit more eaters to come and share in the feast. Yet again, so your friends and co workers, they've never offered to vomit blood in your mouth. They've also probably never offered to share a dead mouse with you. Well, no, but on the rare, on the on the instances where we've had catered dead mouse, Uh, then it certainly people will come around and say, hey, there's food on the question mark table, come and eat

with us. So, well, that's just their moral philosophy or their religion or whatever. Alright, Well we have some some other just quick examples throughout. Dolphins and elephants are fairly complex social animals and display uh various forms of altruism. They form social bonds, and then then they seem to make conscious decisions to help members of their group. Yeah, and so we have all these examples of these are

by far not the only examples. There are just tons of documented examples of animals in the wild or in a conditions seeming to help other animals who are not their direct offspring at their own at their own expense. And obviously we can see why evolution would select for genes that cause organisms to be altruistic towards their own children. Right,

that's kind of the whole point. Your genes optimize your body to have lots of children that can carry as many copies of those genes into the future as possible. But why would evolution produce creatures that sacrifice some of their own safety or resources to help save another creature that wasn't their direct offspring? I mean, wouldn't wouldn't genes that promoted selfishness and cowardice produce the most grandchildren on average? Well?

I mean one obvious answer here is that there's an individual survival advantage in groups, right, Right, The group kind of becomes the meta organism, and natural selection encourages the pro group members of the metal organism and not and not the lone wolves. Now, this is attempting direction to go in, but there are critic of this type of thinking, So lots of scientists have tried to go in this direction, including EO. Wilson in later years. Uh. And this is

sort of related to the concept known as group selection. Right. The idea that natural selection can select for not just the survival of individual genes or the survival of individual organisms, but groups of organisms together. This is also known as multi level selection. But, like I mentioned, this idea has a lot of harsh critics, including Dawkins. I mean, he's criticized this idea. And here's one potential snag. It's true that teamwork pays off, right, But you know what pays

off even more than teamwork? Letting other people do the team Ah. This is the This is the classic um A classroom situation where you've been assigned to groups and you're gonna have somebody in the group who's a real hard work, are very dedicated. You have some other individuals, and you can have at least one person who's just gonna coast right right, Yeah, So you let the rest of the team do the work while you sand bag

and reap the rewards. So if you imagine if you've got wild dogs that have a gene that causes cooperative pack hunting behavior where every dog chips in and does their share of work in the hunt, and in turn, this increases the group's chances of catching prey and then

they all share the benefits. That would be great. Everything's going great if you've got dogs with those genes, But then one of the dogs in the pack acquires a mutation that says, actually, don't help with the hunt, just hang around until your pack mates catch something, and then show up and plunge your face into that delicious viscera.

A dog with this trait would spend less energy hunting, and it would risk less injury, and it would still get the rewards of the hunt, so it would ultimately benefit more than any of the team players, and on average that that freeloader dog would have more offspring, meaning that over time the freeloader gene would become more common than the team player gene, and the pack hunting system

would sort of fall apart. So systems that rely on benefits of group cooperation for the sake of the group as a whole are sort of pervasively undermined by the interests of individual organisms and individual genes within the group, which will sort of inevitably find ways to run counter to the success of the group as a whole. So to sum up, we can show that in general, natural selection will tend to push organisms to favor their own success at the expense of others and at the expense

of their groups. And yet at the same time, group cooperation and selflessness is present in nature, so there must be some way to reconcile these observations, right, yes, and I imagine this is where the green beard comes in. Well, the green beard is going to be one weird way of branching off of this question. Actually, the main answers to this question are not going to be the focus

of today's episode, but we should mention them. So two of the main answers that emerged in the twentieth century to answer this question, or what's known as kin selection and what's known as reciprocal altruism. So reciprocal altruism is basically another way of summing it up, is just the

phrase tip for tat. And while in many cases it can be hard to verify outside of lab conditions, you can sort of build models of organisms that behave on this principle and it does appear to be stable if and the way this works is like this, So if a member of the pack is mean to you, or if they try to cheat and be selfish, you repay them back the same way you're mean to them back you you don't share with them. But if another member of the pack is nice to you, you're nice back.

So essentially you just mirror. You start with the basis of being nice, and then you mirror the you mirror the behavior that people display towards you. Okay, well that that makes sense. I think everybody can fall fall behind that. Yeah. And if you run models like this, it is mathematically stable. Genes that encourage this type of behavior don't tend to get eliminated from the gene pool, but they can reach

a kind of stable equilibrium. But the other main idea is what's known as kin selection, and this was explored in the nineteen sixties by the English biologist we mentioned earlier, W. D. Hamilton's. Now Hamilton's used these quantitative genetics modeling methods, which is like math about how genes are inherited and distributed to show something interesting, It makes mathematical sense for genes to optimize for altruism toward blood relatives other than our own offspring.

So it turns out that for a sexually reproducing species like us, you share the same percent of your genes with each of your children that you do with your full brothers and sisters and with your parents. In each case, you share fifty percent of your genes with them, and to a lesser extent, the same goes for other members of your family. Further removed, you'll share more genes with your aunts and uncles and nieces and nephews than you

do with the general population and so forth. And given this calculus, you can work out how genes that direct organisms to be generous and altruistic toward family members become more numerous in the gene pool than genes that direct organisms to be exclusively selfish and unhelpful to anybody. So if I have a cousin that appears on America's Got Talent, I'm going to root for them in part because they share more of my genes than anybody else that's contestant

on that show. I mean, on average, they probably do. You might have like a secret unknown brother or sister, but yeah, yeah, on average, that's going to be the case. Now. And of course, there are lots of weird ways that maybe things like kin selection or reciprocal altruism uh could be could be sort of modified in various circumstances to generate the mechanisms that create altruism that get applied in

other ways. But it is in the context of discussing this this whole question about altruism and biology in the Selfish Gene that Dawkins also came up with this weird hypothetical idea for one weird type of selective altruism, the green Beard. All Right, we're gonna take a quick break and when we come back we will join back up with Captain green Beard and discuss the details of of

of this idea. Alright, we're back. So we were mentioning how the name of the green Beard gene comes from an example given by Richard Dawkins in The Selfish Gene in n So, Dawkins is pointing out how any arbitrary gene will become more numerous if it makes carriers of that gene friendly and helpful toward other carriers, right, and

that sort of makes sense. It says like, if you've got gene A in your body, gene A does especially well if it makes your body give food and night, you know, nice behavior toward other carriers of gene A. Right, it's just a boost for gene A across the board. So he starts talking about the example of the gene for albinism, which is a genetic condition that causes the carrier to have unusually low levels of the pigment melanin,

leading to paleness of skin, hair, and eyes. And hypothetically, a really successful version of this gene for albino traits would not only produce the visible traits, but it would motivate a carrier to be helpful toward other people who have these visible traits. Now keep in mind, this is

not how the albino traits work in in reality. This is just a hypothetical alternate version of them um And if this were to exist that way, everyone who has this particular gene would have more offspring and the gene would become even more abundant. But would we find something like that in nature? That's the question, and Dawkins writes

the following quote. It is theoretically possible that a gene could arise which conferred an externally visible label, say a pale skin or a green beard, or anything conspicuous, and also attendance to be specially nice to bearers of that

conspicuous label. It is possible, but not particularly likely. Green beardedness is just as likely to be linked to a tendency to develop ingrown toenails or any other trait, and a fondness for green beards is just as likely to go together with an inability to smell frieze is it is not very probable that one and the same gene would produce both the right label and the right sort of altruism. Nevertheless, what may be called the green beard

altruism effect is a theoretical possibility. So this is where the green beard idea comes from. And to be clear, Dawkins is not saying that he expected to find anything like this in nature, right, I mean, it would be it would be a tough sell to say that there's just one gene or one tightly linked group of genes and that does all that work. It's got to produce

the externally detectable trait. It's got to detect that trait in other people, and it's got to make you a special, really nice or in some way manage a positive interaction with other people who have that externally detectable trade. And uh so, so he wasn't saying you'd expect to find it, just that it was an interesting hypothetical possibility, Like he's saying, it's possible that the murder was committed in the library with the candlestick by Colonel Mustard with a green beard

by Colonel ver dear Beard. But but it's just a hypothetical situation, Yeah, and one thing one that would be difficult to come about. But if it did exist, it would be encouraged by natural selection. Right, he's sort of pointing out how natural selection would favor this. You just wouldn't expect it to arise in the first place. But nature is stranger than our imagination. Ah, and this is where we get into actual examples in nature, the green beard.

So this was not what we originally expected, right, I mean, geneticist didn't think that you you discover things like this in nature. But man, the actual world is always surprising us. So let's meet a species. Solenopsis invicta. It sounds pretty serious, it sounds pretty pretty indomitable. It's like the it's like the you know, the Roman Emperor species, And it kind of is because that is the name of the red imported fire ant, which is native South America. It has

spread everywhere from Australia to Asia, the United States. It's all over the place now, and woe to us for that fact. They were first introduced to the United States sometime in the nineteen thirties or forties, and now they are known as an invasive pest with hot needle venom and a ferocious fighting response when their nests are disturbed. In fact, in our episode about the biophelia hypothesis, we

talked about that great video of EO. Wilson trudging through the woods until he finds a red fire ant nest and shoving his hand into it so he can show you how much it hurts. Oh, yes, this is this wonderful footage. I love that he just he stirs them up less and krawling hand lets them sting him in almost like a religious moment. For Yeah, he's so happy about it. If only people in general could find something that they love as much as this man loves these

ants that are furiously pumping their venom into his body. Anyway, another perhaps interesting thing about these fire ants they exist in two sub populations. So they've got so they've got this species, and then two subpopulations have very distinct ways of making a living. One tolerates only one queen per colony and the other has multiple queens per colony. Uh, and those are known as the mono guy in versus the polygone types. You know, one one queen multiple queens.

So in Lauren Keller and Kenneth g Ross published an interesting report in Nature about Solenopsis invicta, and Keller and Ross were studying red fire ants of the polygone variety, that's the kind that has multiple queens. So within the genome of these polyguine sol Anopsis invicta, there is a gene locust called g P nine and a couple of

terms to explain real quick. In genetics, a locus is just the location on a chromosome where you know you can look to find something, where you know you can look to find a gene or one of its alleles. And allele's are variable forms of a gene appearing at the same locus. So, for a simple example, at the locusts q x one, you might contain a gene that

regulates the speed at which your toneails grow. And if you have one allele at q x one, your toneails grow fast, and if you've got a different allele at q x one, your tone nails grow slow. Now back to the fire ants. They've got this gene locust called g P nine with two allele's big B and little B. And because they have two sets of chromosomes. The ants can have three different types of arrangements at g P nine. They can have big B, big B, Big B little

B or little by little by. All right, now, if you were to watch these colonies up close, where a new queen reaches sexual maturity and starts trying to mate and lay eggs, you notice something weird. Only the queens with the two different alleles, the big B little be jeans at g P nine live long enough to reproduce. Why is that what happens to the others. So first, it appears that queens with little be little bee die very young of natural complications. This just appears to be

a lethal recessive combination. And we see this a lot of times in nature where if you've got two copies of this recessive gene, it's it's bad news for you and it can lead to a genetic condition that kills you. But what happens to the big B big B queens. Well, Keller and Ross found out they get violently executed by their own workers. The ants of the colony tear their soul apart. So furthermore, they discovered that it was primarily workers bearing the little bee allele that did the any

work of killing the queens without it. So if you've got a queen that's big B big B, the workers that have a little bee allele will surround it, bite it and kill it because it is it's essentially in some respects, it's like a foreign queen. It does not share the same allegals as it does. Yeah, that's what appears to be going on. But how how does that happen? I mean, normally you wouldn't be able to look at somebody and say you're missing one particular gene that I

have and I'm going to kill you. So what's going on? So the worker ants with that little bijeene at g P nine tend to violently massacre any potential queens that don't carry the little bee gene at g P nine. Uh So it sounds like we might have a slightly modified version of the green beer gene on our hands. But here's a question. How how do those workers know when the new queen has the right a leal or not?

Here's a clue. The author's noticed that sometimes after a worker ant took part in a mob executing a big B big B queen, the worker aunt would then be attacked by other ants in the colony. So you take part in the mob, you kill that big Bi big b queen, then you walk away. Then other worker ants

kill you and you know it. And there's no politics in the insect world, so you know, it's not just some sort of a situation where the assassin has to absorb the blame for the regicide, right right, right, It's not like the king slayer is now being you know, talking to me, like, so what was going on? You have to wonder was something rubbing off on the killer worker And this led the authors to suspect the culprit

is pheromone based. So they tested this by rubbing worker ants against two different types of queens, the big b big be queens and the big Bee little bee queens, and then releasing those workers to their colleagues, and sure enough, the the other workers tended to a hack the ants that have been rubbed against the doom big Bi big Bee queens, but not against the queens with a copy of the little be allele. So to know that we're looking at an actual green beer gene, we've got to

remember the gene should be doing three things. It's got to produce an externally detectable trade. It's got to detect that trade and other individuals, and it's got to provide

preferential treatment to individuals bearing that trade. So it looks like maybe maybe what's going on here is this ants with the little bee gene at g P nine will attack and kill anything that smells like a sexually mature queen unless it also carries the chemical signature generated by the little bee gene, which switches off that kill drive

in the workers. Interesting. Okay, so this looks like, if these findings are correct, a genuine green beer gene found in nature, there's this one gene or some incredibly tightly linked group of genes going off the g P nine locusts. That says, if the queen doesn't have this one gene killer al Right, well, we're gonna take a quick break and when we come back, we have some more possible examples of the green beard gene going on, and we will talk about the wood mouse and the sperm train.

All right, we're back. So, Robert, you promised before we left that you were going to tell me about sperm trains. Yes, Uh so I'm gonna gonna go ahead and back up here a little bit for everybody before we get into just you know, full on with the sperm train. If you were like us, then you've probably read and viewed a great deal of science content about sperm over the years. Uh. This is a topic that pops up in nature documentaries,

science news articles, and seemingly endless academic papers. Well, the sperm it kind of creates a microcosm of the whole natural world, right, Yeah, it is because you know, it's a situation where when when the sperm are competing against each other to go after the goal that's happening on

the inside. On the outside, of course, we have all these various uh mating competition scenarios that factor into our nature documentaries, you know, where different males are competing uh to mate with the female, or multiple males mating with the female, what have you. Uh. So it's interestingly we have kind of this outer war of mating war going on, and then there is an intermating war as well. Because we have all these examples of of sperm uh playing

a role in this outer war. We we learned, um, you know, the violent details of copulation and how sometimes they can deter females from acquiring additional males um. There's also the interesting hypothesis regarding Kama kaze uh spermatozoa in rats and humans, with the hypothetical primary function in these

particular sperm of incapacitating sperm of arrival male. It's kind of like dog fighting sperm or It also makes me think of say a miniature Star Wars space battle taking place inside and that the egg is quite ironically the death star maybe the life star. Well yeah, if you're a sperm, you don't want to blow up the egg. You want to join in harmony with the egg. Well yeah, but but but you have that one individual sperm wants to do it, and it's it's it's a race. It's

a competition life star like that. Yeah, now you kind of grow used to this trend, right, there's competition, ruthless aggression. Sperm is the life seeking missiles at war with their rivals. Multiple matings resultant sperm competition and even mixed paternity. But sperm are also competing against all of their their brethren. Uh. And therefore it's a bit shocking when you realize that

there are cases of sperm cooperation. So most examples of this occurs in the let's face it, freaky world of mosques, as well as the the aforementioned politics free realm of insects. But there's actually an example in the mammal realm as well, as demonstrated in the two thousand two paper. And I love this title, exceptional sperm cooperation in the wood mouse exceptional A plus sperm cooperation. So the wood mouse this is a you know, a Western European rodent. It's small,

but it has tremendous sperm output. The mice in general, uh that they have rather large test these tests or five percent of their body. And if we were if this were the case with humans, to put that in perspective, a male human would have seven points points seven pounds or three point five ms of tests. So these uh, the fact that they're over sexed, it would seem this is helpful because they engage in quote scramble competition, uh to mate polygamously with promiscuous females. As such, you would

expect a lot of sperm competition going on there. Race to the life star. And this is where the train comes in because the wood mouth sperm feature quote extremely long apical hooks and they use these hooks to form together into a store to sort of think of it as a sperm vultron, or, as the paper puts it, motile trains of spermatozoa comprising hundreds to several thousands of cells. These trains these sort of you know hooked together, you know,

wheels of sperm. Uh. These trains allow the bound sperm to travel at greater speeds up to fifty faster than loan sperm out there going on their own. But as they do that, they've got to be given a leg up to these other sperm that they're in competition with. That's the thing, because ultimately only one sperm can get

in there. But they're they're all working together. It's it makes me think of these scenarios where a bunch of villains team up, uh, and then they're all going to turn in turn on each other at the end, but for a little while they're working together, like a sinister six situation. Right. I thought you were going to say suicide squad. Well, I guess that's a similar example. They're all villains, right, are they so untold? I I didn't

see it. I I tried to check it out on HBO, uh to see what everyone was talking about and made it made it just about like five minutes in. But maybe it's a great film. I could be wrong. So in these cases, the hook up occurs one to two minutes after ejaculation, and that's when head to head or tail tail to head hookups occur. So they have hooks on their heads as well in this scenario. But again, only one sperm may enter the life star. It's it's it's like the scene with the you know, trying to

shoot the bolts into the death Star. Uh. So the train starts to decouple about twenty to thirty minutes after forming, and in doing this, many of the individual sperms seemed to sacrifice themselves and uh and some might be even marked for death ahead of time, or there might be competition there at the end. So again, think of a group of supervillains. They've they've worked together so far, but after they kill the Batman or the Superman, they're just

gonna turn on each other. So how do the researchers connect this to the idea of the green beer gene. Well, this is what they say. Quote a green beer gene might evoke such cellular cooperation, although other genetic mechanisms cannot be excluded at this stage. A green beard is a gene that recognizes copies of itself and other individuals and

directs benefits to those individuals. So the idea, here's the green beer gene would be the deciding and factor with which sperm you're going to team up with in this battle, because you certainly are not gonna gonna want to hook up with sperm from other uh individual mice that have made it with this particular female. Right. Interesting, So so they're saying this could be one explanation of the behavior they're seeing here. Yeah, this is Life Race two thousand.

All the cars are heading out, but some of these cars are realizing that they can work together and form a train uh to to to out maneuver and and uh and and outperform their competitors because some of the cars have exact copies of the driver in each one. Yeah, like multiple Frankenstein's that was a deep cut. I scared

somebody off there. Roger Corman's Death Rays two thousand, if you want to want to get all of that, Okay, So that's another So there really does appear to be a green beer, you know, if the observations are correct, there really does appear to be a green beer gene working in the fire ants. Uh. It looks like green beer jeans are a good candidate to explain what's going on here in the sperm trains, but it's not a

sure thing. Other mechanisms might explain it. In two thousand and eight, I should just mention quickly there was one paper that seemed to identify a green beer gene that was driving cooperation in yeast cells, and that that gene was called f l O one. But just recently I was reading about how there is apparently green beer gene activity in slime molds. Our old friends. Oh yes, yeah, yeah,

this was pretty interesting. So to refresh slime molds, which which I like to compare to science itself at times. I think it's a good metaphor for it. Slime molds are microbes that live as single celled organisms, but they kind of vultron together into a great communal metal organism that quests after food. It's a two vulturo on episode. Yeah. Uh, and you know, there's some fabulous experiments that show the sort of communal intelligence that it has, like a very

non non non human form of intelligence. So it's problem solving ability. Yeah. Well, in March of this year, geneticists from the Universities of Manchester and Bath discovered that these individual cells are capable of choosing who they joined forces with. So it's not just you know, every um slime mold individual is gonna come together like they're gonna be a little bit choosy and uh. And it seems that green

beer jeans factor into it. Oh okay, So you're a slime mold cell and you've got this one gene that says, if there's another slime slime mold cell that has this same gene, join with them and conquer the maze. Okay, yeah, it's so it's pretty straightforward in that regard that the gene in question encodes a molecule on the surface of a slime mold cell and it can bind to the same molecule of another slime mold cell. Now, most my

slime molds strains have a unique version of the gene. Okay. Now, there's a great deal of diversity in slime mold green beer genes, according to the study, but individuals show a preference for cells with like or similar green beer genes, and the assembled whole the resulting you know, larger mental organism slime mold. Um, it actually performs better. It does better if it's formed of preferred partners as opposed to

you know, non preferred partners. As such, these beer genes listening to govern in a particular specific cooperative behavior in the slime molds. So the way it works is it just makes you sticky for other slime mold cells that have this same gene. Yeah, basically like on a very it's it's kind of just like the real pro gloves. Yeah, it's like the simplified version of why liking the same band um binds you to somebody else. So to summarize going off the paper here, Uh, the green beer genes

achieved the following in the slime mold. So they predict partners specific patterns of cooperation by underlying variation in partner specific protein protein binding strength and recognition specificity. Uh. They also increase fitness because they help avoid potential costs of cooperating with incompatible partners. And also they generate a homophilic binding spectrum that allows individuals to identify appropriate partners with

whom to engage in cooperation. And its states that it also serves to stabilize cooperation in the face of selective pressure for the emergence of quote false bearded cheaters who by providing information that can be used to differentiate compatible from incompatible partners. So this is a new ripple. This is a new ripple. So we started with this hypothetical idea that Hamilton and Dawkins talked about, saying that it's

not necessarily going to be found in nature. It's just one hypothetical thing that could work if it ever were to arise. Now we're finding examples of it in nature. The green beard gene, the gene that says, hey, I see you have this gene too. I like you. I'm going to treat you right. But now we see that there are false beard pretenders. You could have a gene that in fact signals the same thing as having the gene, or something that could easily trick you into thinking they

have the gene but they don't have it. Well, you know, I'm reminded of the slime mold moving through the maize that you know, our scientific uh quest to understand the universe. So anytime we find something new, there's always some new ripple, some new complication, uh. And and and some new level of the complexity of life. So what is the what is the liking the same band equivalent of the false spirited cheaters? Somebody who you think signals liking the same band,

but in fact they do not really like them. Is that the the fake tool fans you were talking about at the beginning, maybe, or maybe a better example would be, like there might be a band that was really popular and you dig them, somebody else doesn't. Really they're not They're not a true fan. They just they're maybe a little nostalgic for it. Or they remember listening to this band in high school. But where have they been, you know, the subsequent decades. So they've got the bumper sticker on

the back of their car. But if you started talking to them, you would find that the compatibility you were seeking is not really. It's all superficial, right, or maybe

it's Uh. It also reminds me I think it was Kids in the Hall skit where somebody's trying to buy a copy of The Door's Greatest Hits at the CD store and this guy comes in Elections and was like, no, you have to start with the first album, and then you have to listen to it, like there's very specific instructions about where you listen to it, how long you listen to it, and then only then can you move on to the second album, and you have to go

in order. So he's instructing him how to be a true long term fan and not like a cheap skip to the greatest hits fan. How to be a true pretentious jerk. Do pretentious jerks glom onto each other in the same way that Greenbeard slime mold cells do? I don't know, or maybe I mean I guess they do. But you could also argue that they don't have the binding factor. They're just too pretentious about their their stuff.

They can't actually enjoy it with other people because they have to be the they have to be the biggest fan in the room. They have to be the smartest fan in the room. But we're getting into the human complexities here of of of sharing and things. I think we've run more fild with our metaphors and we've gone

off the deep end. Anyway, picking up from our intro to this episode, where we had to lay the context about the discussion about altruism and biology and the idea about the different levels of selection I've been thinking that this would be daunting because it makes biologists uh ruffle

their feathers and get very upset. I think maybe in the future we should try to do a big episode or maybe a two partter on the levels of selection debate in biology, like this big controversy over whether group selection is a real thing or not, or whether whether there's also arguments about the arguments, like whether the argument is real or whether it's just semantic um and so I think I think there's a lot of interesting stuff there, but I know it's a big, thorny, controversial issue that

has a lot of uh petty sub issues. Well, no, that could be fun. I mean, who knows. Maybe it's a topic that it would be Uh it would be sensible to bring in a guest to help us and navigate all the controversies. Well, maybe we need to bring to two guests, one that take each side. Ah, and then we turned into a debate show, but we're not we're not going to do that. Well anyway, if that's something you would like to hear, maybe you should let

us know. Yeah, yeah, for sure. Hey, before we close out here, Uh, this is one of the first episodes that we're recording after the total solar eclipse here in North America. Uh And, as previously stated, you went up to Tennessee to to check it out, to be within the line of totality, and and I went up to Blue Ridge, Georgia in the North Georgia Mountains and observed it as well. So what are your thoughts? It was?

It was amazing. I was trying to uh convince everyone that we should go up to the path of totality, and they were like, but hey, isn't it like totality here in Atlanta. And I was trying to explain the difference between like ninety nine point nine and is is apparently huge. And I'm glad we went. I'm glad we did it. It's I don't want to sound flip when I say this, but it was a religious experience. I mean, it was a really truly astonishing thing. I've never seen

anything like it before. It was amazing watching all the different physical changes going on around us. As the totality approached. There was this moment where it was probably about as the sun was about seventy covered, maybe a little bit more, that I started to notice that there was still still the appearance of sunlight all around me. So it was like a bright summer day, but suddenly there was I

didn't feel the heat anymore. The sunlight felt cool, and I could stand in the direct sun and my skin didn't have that that radiation reaction it normally does when you're standing out in the direct sunlight. There. I don't know that. The colors became so strange as it came on, and then once the totality hit it was true what I read in advance that said, you know, it can feel like it's over in seconds. It totally did. I was just standing there gaping at it, and then I

after almost no time at all, it was over. Yeah. I was really impressed by it as well. I mean, aside from just the the the actual spectacle of the

full eclipse, just seeing the ring there in the sky. Uh, you know, all the subtle stuff was very in a way unnerving, and and and and he felt like you were kind of crossing over into, uh, you know, an abnormal realm because that you had this sense that it was it was dusk, but there was no sunset on the horizon, you know, there was this uh this also, I certainly observed the changes in the animals because I was in the forest in the mountains, So the cicadas

all died down, and it suddenly the cicadas stopped making their noises and the crickets started up. Yeah, I observed that too. Up in Tennessee. We heard the nighttime insects begin to whir to life. Another thing when we saw moths as well, Like suddenly there were moths flying around.

So I got to see because I knew in advance to look to the west, like we talked about in our eclipse episode, there were some clouds in the sky to the west of where we were, and I kept my eyes focused to the west right as the last of the Bailey's beads were fading, and as it was coming on, and I saw the shadow pass over the clouds to the west of us, and it was so cool to see like that, we had white clouds and

then suddenly black straight over them. And of course everyone experienced the drop in temperature, but we also witnessed what I believe was, you know, weather changes because of that, because the it was a little bit cloudy, and the clouds were on the just teasing with us with the possibility of obscuring the total eclipse, but it held off. But then right after the eclipse occurred and was and and and the moon was big getting to move out

of the way of getting away again. Uh, there was this um suddenly a lot of cloud cover moved in and then it almost immediately started raining. Yeah. I think we had some strange weather the rest of the day. How about your dog, Charlie? Was he there? No, we left him at home. I we thought about bringing him, but the place we were going was it was a college campus up in up In, Tennessee, and we didn't know how many people would be there, and we didn't

want him to get upset if there was a big crowd. Um, so we we just left him at home and he was fine. Well, Uh, my son came. He really enjoyed it. It was just a great experience. So uh, And I know I reached out on the Facebook on social media. A number of our followers there, our listeners there, they chimed in those that either experienced the partial or the total eclipse. And certainly we'd love to hear from anybody else who has particular observations about how the environment reacted

or or how you reacted to the total eclipse. Uh, you know, we would love to hear your experience as well. One last thought, photos don't do it justice. Yeah, absolutely not. I mean I've seen tons of photos of past solar eclipses, but it's not like seeing it in person for yourself.

So if you ever get a chance in the future, if you want to, you know, if you're in South America, or you want to fly to where one of those total eclipses in upcoming years is coming, or if you're in the United States and you just want to go ahead and start planning for it's really worth it. It's

something unlike anything else you'll see in your life. All right, Hey, In the meantime, waiting for the as you wait for the next episode of Stuff to Blow your Mind to come out, head on over to Stuff to Blow your Mind dot com. That's where you'll find all the podcast episodes, including our episode on the on the the the solar eclipse then that came out in the last week or two.

Be sure to check that out. Also, you'll find links out to all our various social media accounts such as Instagram, Twitter, Um, Tumbler, and Facebook. Hey, and on Facebook, we have a group now the discussion module. Be sure to check that out because that's a great place to have more long form form discussions with other listeners and UH and sometimes the

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