SciShow Tangents - Mutation with Trace Dominguez

Episode Date: April 30, 2019

This week, we’re joined by Trace Dominguez from the YouTube channel Uno Dos of Trace to talk about genetic mutations! Tiny changes in an organism’s DNA sequence can lead to big variations or absolutely nothing. It’s just a roll of the dice! So what mutations have shown up in modern humans—different bones, livers, or even eyeballs? What is “foreign DNA” and where does it even come from? And can anybody name as many X-Men as Sam?If you want to know more about any of the topics discussed today, check out these links:[Truth or Fail]Hypoxia:https://www.sciencealert.com/indonesian-bajau-genetic-changes-adapt-them-to-aquatic-lifestyle-2Bones:https://www.the-scientist.com/notebook-old/the-worlds-densest-bones-47155https://www.nejm.org/doi/full/10.1056/nejmoa013444https://www.ncbi.nlm.nih.gov/pubmed/28893644Smoking:https://www.latimes.com/archives/la-xpm-1994-10-17-mn-51362-story.html[Fact Off]Tetrachromats:Colchicine and watermelons:https://csuvth.colostate.edu/poisonous_plants/Plants/Details/79https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4656054/https://scialert.net/fulltextmobile/?doi=jbs.2013.277.282https://naldc.nal.usda.gov/download/CAT71326739/PDFhttps://aggie-horticulture.tamu.edu/newsletters/hortupdate/hortupdate_archives/2000/may00/h5may00.htmlhttps://blogs.scientificamerican.com/artful-amoeba/for-plants-polyploidy-is-not-a-four-letter-word/[Ask the Science Couch]Foreign DNA:https://www.eurekalert.org/pub_releases/2015-11/uonc-ahc111815.phphttps://www.medicalnewstoday.com/articles/290835.phphttps://genomebiology.biomedcentral.com/articles/10.1186/s13059-015-0607-3https://royalsocietypublishing.org/doi/full/10.1098/rspb.2009.1679https://www.ncbi.nlm.nih.gov/books/NBK7934/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6177113/[Butt One More Thing]Beautiful buttocks:https://www.nature.com/news/2002/020917/full/news020916-3.html

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase starring some of the geniuses that make the YouTube series SciShow happen this week. Taking my place on the science couch is a thing that is not me, a very special guest. It's a Trace Dominguez. Hello. Trace is of the YouTube series Uno Dos of Trace, which you can find at youtube.com slash Trace Dominguez. Can you spell your name for me?

It is T-R-A-C-E and then D-O-M-I-N-G-U-E-Z. Thank you for coming. I've been watching you on YouTube for many years. Thanks, thanks. Yeah, this is exciting. I've never tangented with y'all. I'm excited to go on tangents. It's great to make a thing with you.

Yay. Trace, what's your tagline? Stickers are great. Oh, God. Do you like a... Did we provide you with a sticker? I got a SciShow sticker, and I'm really excited about it. We have also SciShow tangent stickers that are available at DFTBA.com, designed by

Hiroko Matsushima. And we're also joined on the Science Couch by Sari Reilly. Hello, Sari. Hello. I'm here, too. How are you feeling about today's topic? Oh, I'm excited. I'm a little bit nervous. This is something that I paid a lot of money to get a piece of paper to say that I know it. So... You better know it. I better know it. Sorry, what's your tagline? Just a floating head. Oh, yeah.

Which is a visual joke. Sorry, your shirt is exactly the same color as the couch, so we are all a little bit thrown off. Just imagine what color the couch is. Pick your favorite color. Everyone knows. It's canon. The science couch is yellow. If they're true HFS fans from back in the day, they know what color the couchches. Pick your favorite color. Everyone knows. It's canon. The science couch is yellow. If they're true HFS fans from back

in the day, they know what color the couch is. Sam also matches the couch that he's on. A little bit. He's sort of not a floating head. He's like partially invisible. Like predator camo. You need some leaves on the couch too. Sam Schultz is also here. Hi, Sam.

Hello. What are you working on these days i'm working on the scishow science kits universe unboxed is what they're called yeah and you can order them online universeunboxed.com boom i believe that's so exciting yeah and there's videos that go along with it so you can see how the experiments work yeah you can see hank getting goofy in a lab coat it's been really fun yeah yeah uh and. And Stefan is, oh, sorry, what's your tagline? Just a floating butt. Together we make a human.

No, a butt and a head together does not make a human. Yeah, you connect them. There's two holes. That's a lot of the emulsification. Oh, right, right, yeah. You've got the digestive

system is complete. Yep. That's all you need. Stefan, hi, how are you? Hello. I'm doing all right. Where should I get new Yep. That's all you need. Stefan, hi. How are you? Hello. I'm doing all right. Where should I get new shoes? That's a strange question, Hank.

I have really wide feet, so I have to order large shoes. Do you have a smashed pinky toe? My pinky toe is all squished. I have a squished pinky toe. My pinky toe nail is like a disaster. Oh, yeah. It's like a joke. I look at it like, why are you here? What is your purpose? I don't know how to trim it, so I just like grab it. Oh, yeah. It's like a joke. I look at it like, why are you here?

What is your purpose? I don't know how to trim it, so I just like grab it and pull it off. Yeah, and then you're like, did I get all of it? I don't know. This is all me, too.

Sari is horrified. The rest of us are like, yes, exactly. You just pull off your toenail and expect me to accept that as like, yes, this is a grooming thing that I do. Remove big chunks

of my body. It doesn't feel like anything. It just comes out. Barely hanging on. Is that your tagline, Stefan? Yeah, sure. I am Hank. I'm really excited to tangent today. I don't have to do anything except host.

I can't win, but I didn't have to prepare any science facts. Which seems like a great deal to me. He can't lose either. I can't win, but I didn't have to prepare any science facts. Yeah, you can't lose. Which seems like a great deal to me. You can't lose either. I can't lose. That's my tagline. Hank Green, can't lose.

All right. Every week here on Tangents, we get together. We try to one-up a maze and delight each other with science facts. We're playing for glory, and we're also playing for Hank bucks. We tend to go on tangents sometimes. If we deem a tangent unworthy, we will take away one of your Hank bucks, and you can go negative. Now, as always, we are introducing

this week's topic with the traditional science poem this week from Sam. You may know mutants as people who shoot optic blasts or can read people's minds or can run really fast, but my friend, you are wrong. The reality is mutations are everywhere. I'm telling you this

the reason your cat has a cute squishy face is because of slow dna changes to the whole feline race it's why spiders spin webs and newts have cold blood it's why sloths do whatever it is that slots does all these so many things you could have just changed to find a better rhyme, but you didn't. Like what? I don't know anything. Newts have cold blood. Many animals have many traits. You could, like, why, like, sloths have the fuzz?

This is an unprecedented interruption of the time. Fart. All these changes in time slowly add up and become every living thing ever like every single one but while that is profound and amazing i will have to admit i still wish i could fly or shoot claws out of my mitts so sari our topic is mutation uh what is that it's genetics so genetic mutations are when dna gets changed permanently in some way and dna is important because it codes for rna which codes for proteins which make up all the like the functions that all your cells need to survive to do the things to do the things that make you human yeah um and dna codes for all that. That's why mutations can change the way that things look or act or the way their cells act because a small change in DNA can cause a

change in a protein, which changes a whole system. If it's on purpose, though, is that a mutation? Like if I intentionally change a genome, is that a mutation? So you can intentionally introduce what's known as a mutagen, which is a compound or something like radiation that can mess with DNA and cause a random change. But I think mutations are inherently random changes to DNA. And if you insert a gene to a specific spot that you mark and use genetic engineering techniques, that's genetic engineering. It's not mutation. Mutation has to be random i think so yeah yeah okay wow i didn't know that and it can either be like one dna base so i don't know you have atgc and if you swap one letter out for another that's like a point mutation and that happens all the time where our cells are constantly

mutating yeah we have a lot of point mutations going on all the time. Sometimes those affect the way a protein forms, and sometimes they do nothing because it's already in a non-coding region of DNA, so we don't really care. Or it can be a whole chunk of a chromosome that gets swapped out or mixed around or part of a gene and when bigger things happen that those are usually when bigger phenotypic changes happen or things like systems break right as a gene breaks and you needed that to see hunk of stuff either got taken out or got shoved in and the protein is like i'm gonna be different now yeah or like entire genes could be copied multiple times and sometimes that adds a lot of function to it sometimes that does nothing and you just have a bunch of copies of the same gene. And sometimes, this is interesting, you'll have the same, like a slightly different copy of the same gene

and that protein will be very similar but somewhat different and that will allow for, for example, animals that can exist at multiple different temperatures often have multiple copies that code for a different protein

that's basically the same but works better, but like actually works at a high temperature and one that works at a low temperature. That's cool. All right, it is now time for Truth or Fail. One of our panelists has prepared

three science facts for our education and enjoyment, but only one of those is real. And the rest of us have to guess which one is the real one. And if we get it right, we get a Hank Buck. If we don't, then this week, Stefan we get a Hank Buck. If we don't, then this week, Stefan will get that Hank Buck. Stefan, do you have three mutation facts for me? I sure do.

Can you tell me what they are? Yes, I can. Fact number one, several populations of humans who have lived at extreme elevations for thousands of years have mutations that help them survive there in places where there can be as much as 40% less oxygen than at sea level. But if you go below sea level, oxygen is also much less available to us. But Jiao people in Southeast Asia who spend much of their time fishing underwater have a similar mutation which gives them an increased level of hemoglobin in their blood, allowing them to store more oxygen and dive for over three minutes while holding their breath. This is a good fake fact. I like that fake fact. That's a good one.

Number two. There are people with a mutation that has been linked to low bone density, but a different mutation of the same gene can also cause extremely high bone density, making their bones seemingly unbreakable. One downside to this mutation, though, is that these people can't go swimming

because their unusually dense bones cause them to sink. Okay. Okay. Okay. Great fake fact. I like that one. That's very good. Fact number three, 38 members of a single family living in a small town in Italy have been found to have a genetic mutation that can be traced back to a single family member that was born in 1780.

The mutation has been linked to significantly lower rates of lung cancer. So all of them are heavy smokers. And some of them being in their 80s and 90s none of them have gotten lung cancer yet uh also but i that so i feel like i've heard about a weird italian family for sure i don't remember what it was that was weird about them i feel like there's so many stories of this one mutation is just this family and so they do this thing i don't know like they. I think I read something about HIV resistance in certain families or groups of people that were resistant to the plague, I think.

Oh, like the same people were resistant to the plague and to HIV? Yeah. And I don't know how those things are connected because one's a virus, one's a bacteria infection. Okay. So I'm going to ask you about this Italian family and their lung cancer okay why like just because i'm not gonna get lung cancer doesn't mean i'm gonna smoke yeah like that you presented it like they like of course now that

you know but also it's obnoxious i mean maybe they just think like oh we seem to live a long time regardless of what we do so we might as well do all the bad things that we enjoy. I'm just speculating. Do they also just like eat like sticks of butter? Yes. Let me go ask them real quick. I'll shoot them an email.

I would do that. Eat butter? Or email them. It was fine. I feel like if I knew that I wasn't going to get lung cancer from smoking cigarettes, I would still just vape.

I don't vape. Wow, dude. I didn't vape. Wow, dude. I didn't know you were that cool. Everybody looked at me really hard. There was a lot of silence there. So what were the other ones? So also, yeah, to do the things,

we had humans in Southeast Asia, number one, who can dive longer because they have more hemoglobin in their blood. I feel like I've seen like a documentary on this. Yeah, I've definitely seen

these divey people. I feel like a pretty video of some on this. Yeah, I've definitely seen these divey people. I feel like a pretty video of some dude walking along on the bottom of the... Yeah, people who are good at diving, and there's a reason they're good at diving. I can't remember what it is. We also have high bone density people who have nigh unbreakable... What was the word you used? Seemingly unbreakable. Seemingly unbreakable bones.

Okay, I have a point of order. Deliberately vague. I have never broken a bone, and I am terrible at floating in water. Can you swim at all? I can swim quite well, but I have to swim. I can't float. All the like floating tests, I can't do it. I always sink.

And you sink. And I sink. So maybe this is real. I don't know. I have decided. I am an Italian family of 38 people who like to smoke cigarettes. Oh. Wow. That. Wow.

That's nice. You are? I am. I didn't know that about you. I'm going to go with bones because I have broken a bone and I float really easily. Opposite of trace. Using these two data points. That's my guess.

I feel like that's all you need in science is two data points. Yeah. Totally. I got a good gut twinge about the diving people. It sounds familiar. Mm-hmm. Sounds real. I think I heard it before.

Yeah, same. I feel like that documentary video just keeps playing in my head. It's like two seconds long. Yeah. Like a gif. And it's like the sun's filtering through the ocean and someone's swimming to the bottom. Yeah, definitely. And they're saying.

So I'm going to go, yeah, divers. Stefan, the real fact was's swimming to the bottom. Yeah, definitely. So I'm going to go divers. Stefan. The real fact was the bones. The bones! I don't believe them! Dense bones. That seems extra fake. No, it was extra real.

Just a normal amount of real. So you said they can't swim. Yeah, so they all seem to be related and they discovered it because the one guy got into a car crash and didn't break any bones. I assume it was a bad enough car crash that they would have expected him to break bones. And then they sent him to a bone doctor.

And he was like... Bone doctor? The bone doctor was like, hey, you've got bones that are eight times denser than normal. That's weird. Eight times denser than normal? That is a lot. So they ended up tracking down all these these people and there's like uh i don't know how many but there's a bunch of them that seem to be related have this same mutation and they all have super dense bones none of them have broken a bone wow in their lives uh and one of them could

not get a hip replacement because they weren't able to screw the prosthetic into that person's hip wow yeah it's very weird uh and and the guy who got into a car accident uh so that he could not swim and always sunk i mean that's really dense eight times that's a lot where the other so but tell me about my italian family so they're real right uh their italian families are real fact and but i it's like based on an article from 1994 in the la times uh that was about an italian family of 38 people who had a mutation that made them resistant to heart disease okay they were all smokers or almost all smokers for some reason. But they, mostly they were like eating. Yeah, smoking does cause

heart disease. Yeah, that's true. But also lung cancer? Yeah, that's more of the risks. That seems, yeah. So it doesn't really make sense. But they had like terrible diets

and were like taking advantage of this mutation. They were living life for the fullest. So it was real, at least according to a 1994 article in the LA Times.

Yeah, which I didn't verify. So who knows? I was making it it up so it's all good stuff i said about the people living in high high elevations is true at least for the people who live in the andes they have more hemoglobin um people who live on like the tibetan plateau and other places don't it's like a different way that they cope with high elevation but the bajau people in southeast asia uh the way that they cope with diving for a long period of time is by having larger spleens up to 50 larger so it turns out that for humans just in general you have in your spleen like a bunch of extra blood and then in response to diving without equipment one of the things your body does

is squeeze all that blood out into the circulatory system so that you can... I think part of it is maintaining the pressure inside your lungs. And then part of it is just so that you have more oxygen. Yeah, because it specifically stores oxygenated red blood cells, right? So it's like you have that extra store that doesn't need to flow through your whole body.

It's just there, ready, squish out into your blood system. I honestly didn't know what the spleen was for. I think it does other stuff too. I thought it was an organ that cartoons made up. I swear to God.

I'm like, that sounds like a funny thing that they made up. Yeah. Next up, we've got the fact off, but first, a word from our sponsors.

Welcome back, everybody. We got our Hank Buck totals for you. Sarah, you have one Hank Buck. Trace, you got nothing. Oh, man. Yeah, I know. Me too totals for you. Sarah, you have one Hank Buck. Trace, you got nothing. Oh, man. Yeah, I know. Me too. It's okay.

Stefan, you got three. I'm cleaning it up, raking it in. Hit me with it. Sam's got one. Do you have anything to say about that? That's about as many as I normally have. All right. So I'm very excited for Stefan to be so far in the lead. Me too.

Oh, man. Now it is time for our fact off, where two of our panelists have brought science facts to present to the others in an attempt to blow their minds. The three of us have a Hank Buck that we can award to our favorite fact. And to decide who goes first among our science couch participants here, Sari and Trace, we're going to go back and forth naming X-Men and this is going to be judged by Sam. I'm so stressed out. My heart is beating so fast. Trace, you go first

because I think you have an advantage. I'm going to go with Cyclops. Sure. He's got a thing. Maybe the easiest one. Well, the second easiest one. Oh, gosh. Jean Grey. That's a yeah. Well the second easiest one. Oh gosh Jean Grey is one perfect um Beast good Quicksilver perfect Wow

I'm gonna go with Professor X North Star oh Oh, my gosh. Wait, is North Star a mutant? I have never heard of this. I have to Google that. I have to, too. North Star's in Alpha Flight, but I think he's a mutant. I think Alpha Flight's all mutants.

I'm going to go with Angel. Yeah, mutant. Perfect. He's got wings. From Buffy? Yeah, Angel from Buffy. Yeah, the insult to the vampire. Flame Boy. Flame Boy? No. Human Torch. from buffy yeah the vampire vampire flame boy flame boy no human torch

you can't just say flame boy and then come back after we say no okay trace you go first so uh my science fact today is about your eyeballs. So in your eyeballs, you have rods and cones, and they enable you to see in the dark and also to see color. The rods do low light vision and the cones do color and also spatial acuity, right? So we have three different types of cones, though. Mostly people just think of them as either one or the other, but there are three different types of cones, one for each of the major color groups that we can see. They're each sensitive to blue, green, or red. Now, those cones are coated by the X chromosome. That's where they live. So that's why sometimes men specifically will be red-green colorblind. But only red and green are coded on the X chromosome by the OP1, OPN1 family of genes.

And so the long is the red, the medium is greenish-yellow, and then the short is a blue. The name for that is trichromacy. It means three colors. And then that's why it's rare for people with two X chromosomes to have red-green colorblindness, where people with XY have the regular sight sometimes and sometimes

have a dichromacy or two-color sight. So that brings me to the blue receptor, which is coded on chromosome 7, and each of the cone gives you 100 shades, so 100 cubed. You get about a million colors if you're a trichromat. But because blue is separate, you could also have a mutation on the X chromosome of your red-green chromosome, giving you a shift not away from red-green, but into a different spectrum altogether. So then you can have four cones. So that would be called tetrachromacy, and the first evidence of it was in 1948. Is that a thing that people can have humans women specifically yeah can have tetrachromacy oh it's been also seen in a lot of different animal species sure you know fish and like mantis shrimp have i think five or something it's crazy i don't know but uh four coned women do exist these different groups of people. They think roughly 12% of women might be tetrachromats

and not know it, which is so cool. How far into that range can they see? So it depends on your mutation, but they think essentially if you imagine 100 shades with four cones, you could see 100 million colors. So you can see potentially millions more shades than an average person. And the problem is, which I think is just amazing, we have trouble finding them because they don't know that they're seeing more color. That's just how they live their life. So they write up, said, we would never be able to make a satisfactory match because the participant would be able to sense color gradations beyond those available on the test. Which is great. And I thought to myself, a dude wrote that.

Yeah. Because if a tetrachromat scientist created a tetrachromat test, they could potentially see the same thing. So you have to, like, find out that you're a tetrachromat somehow, either through genetic testing or by being like, you can't tell the difference between those things. Right. Yeah. And so then there's this woman who's British, who's an artist and has been interviewed a bunch because she's one of the tetrachromats who's like out there, I guess, one of those mutants. And she said, quote, when she looks at leaves, just like regular old leaves on trees, she sees around the edge, orange, red or purple in the shadows. And you might see a dark green for you, but I would see violet, turquoise, and blue, like a mosaic of different colors.

What? When she looks at leaves, and I'm just like, what is that? You just crushed my dreams. I was like, maybe I am. Maybe I'm one of the told me that I have two X chromosomes. But all leaves are normal. Yeah, leaves look pretty normal to me. I'm good at the gradient tests online where you can like, let's sort these colors by gradient.

It's neat because it's like, it would be impossible. Color experience is so personal. There's no way to know what someone else sees, right? So they said, well, even if you asked her to describe what she can see, it'd be like trying to describe red to someone who was born blind. Like, how do you describe that? Or like what the fourth dimension looks like to us boring three-dimensional people. The thought like, do we all see the same colors as the same colors? There's no way to know thought.

I feel like it's one that everybody has at some point in their life. And it's just like oh man I gotta tell my dad about this so what you're saying is yeah my dad you don't go to your dad every time you have like a cool philosophical thought no he texts me his a lot though Sari do you have a fact for us

no I just didn't bring one today oh well the truth is I do have a fact I thought it would be funny. It's not funny. It was a bad joke. Cut it, Sam. No, I can't. It's too late. Okay, so a lot of the time when you hear about mutagens, radiation comes up. Like, it's in all the superhero stories.

Radioactive spider, radioactive gamma rays, or things like that. Cosmic radiation, we're worried about. DNA damage from UV light. But chemical mutagens are really fascinating too because of all the ways that they can mess with cell biology in multiple ways besides just damaging the DNA directly. So I'd like to introduce you all to a compound called colchicine, which is a toxic chemical found in purple flowers called the autumn crocus.

Specifically, it's an alkaloid, so one of those nitrogen containing compounds. And humans, by and large, use it as a medicine. So some sources have said that it is mentioned in Egyptian medical texts to treat inflammation. And that's the main genre of things that it's useful for. Nowadays, it's in gout medication, which is a form of arthritis that involves inflamed joints or blood vessels swelling or things like that. And we've kind of narrowed down its mechanisms of action. The big thing that it does is mess with the formation of microtubules. And microtubules are a structure that influence cell things like shape, and they can help cells move sometimes.

They help with ion channel stuff. And really importantly, they help with cell division. And so during cell division and mitosis, chromosome segregation is a big part. So you replicate all the genetic material inside a cell. And then as the cell divides, you need to divide up that genetic material so you have two identical cells. And if something goes wrong in that process, usually bad things happen. Because colchicine influences microtubules, it can mess up the segregation step. So without microtubules, all the chromosomes could end up, like everything will get replicated and then all the chromosomes will end up in one of the daughter cells in mitosis and the other one will just be empty. Like it doesn't split up.

Wow. And that situation is called polyploidy, where you have more than the number of sets of chromosomes that you should have. So because it affects the genetic makeup of cells, papers call this a mutagen, even though it's not a point mutation, which I thought was kind of interesting. Yeah. It's not even a mutation to the genome. It's just there's extra genome. It's like double the amount of genome every time? Yeah. Yeah. And so there's mutagenic activity.

And I assume that, so in animals like humans, having way too much genetic material in a cell is bad. It's very bad. Our bodies don't know what to do with it. It means cell death usually. Yeah. But in plants, they're just chill with it for some reason. They're just fine with having multiple copies of their genome at once and can still survive.

Good on you. Yeah. Way to go, plants. Or one of the big things that we've created because of it are seedless watermelons. That's how we got those. The question you got to ask is how do you get a seedless watermelon if you got no seeds? How do you get a seedless watermelon if you got no seeds? So what they do is they dose, I think they soak seeds in colchicine solution to mess up the cell division in a seed.

Watermelons normally have two copies of chromosomes, so they're diploid like humans. And so if you dose them with colchicine, they'll end up with four chromosomes. So they'll be tetraploid instead of diploid yeah uh you can cross a tetraploid watermelon with a diploid watermelon and get a triploid watermelon that has three sets of chromosomes oh wow wow so kind of like you create a liger or a mule or anything that where the chromosome mismatches and that watermelon is seedless because if you have an odd like a mismatched set of chromosomes yeah it's sterile it's a sterile watermelon you have an odd, like a mismatched set of chromosomes. Yeah, it's sterile. It's a sterile watermelon. You have to cross it every single time. Yes. Which is why being like a seedless fruit farmer is really, I don't know if it's more expensive, but it's more complicated.

And that's it. That's the fact. So like the reason we have seedless watermelons is because of this mutagen. Weird. That's cool. That's neat. Yeah. Okay.

so that's neat yeah okay uh so we've got polyploidy watermelon seedless colchicine doped stuff from sari and from trace we've got uh tetrachromatic ladies of the world have no idea how many colors they can see yeah i have one question though wait a minute so the thing with the watermelons yeah it's not exactly a mutation they call it a mutation is that just because they don't have another thing to call it i think it falls under the category of manipulating genetic material in a way that would happen by chance because it is a toxin being introduced into the cell it's not like scientists controlled taking the chromosomes out and putting them in right and i think they call it a mutagen because after this happens there's probably crossover events that happen

that where the chromosomes can exchange information and things like that okay i'm gonna give mine to trace it is very cool i would give mine to trace too oh i'm gonna give mine to Trace. Ooh. It is very cool. I would give mine to Trace, too. Oh. I'm going to give it to Sari, because I like bathing seeds in... No, I don't do this, but I like the idea that we do this. And we have to do this. Yeah, it's one of...

Yeah, Stefan's got a whole bathtub full of colchicine at home. I like watermelon, and I like seeing stuff. So I think I'm going to go with Trace. Oh, man. I got some bucks. I went from zero to two so quick. You did. Wow.

It's time now for Ask the Science Couch, where we ask listener questions to our couch of finely honed scientific minds. I'm not on the couch today, so I don't have to do anything. Sam, do you have the question for us? I do. At McLekstick asks, I've heard 17% of tardigrade DNA comes from other organisms. Do larger human-sized animals

get DNA from other organisms as well? I'm going to rephrase the question. If I put a bunch of snakes in my mouth, can I be part snake? I'm going to rephrase the question. If I put a bunch of snakes in my mouth, can I be part snake? I'm going to go with no. Yeah. No.

So, unanimous vote. Yeah. I'm going to be a snake man. I mean, you would be a snake and a man. So, you can't just steal genes from whatever you want. You can't walk around, eat a snake, touch a snake, touch a plant and be like, I want that now. But what this question is asking and what that what Hank's like rephrasing is asking foreign DNA doesn't come from like the tardigrade coming in contact with another organism and then incorporating that into its

genome somehow. It usually comes from microorganisms like bacteria or viruses that work by different mechanisms or like bacteria or viruses that use different mechanisms to incorporate their genetic material into another organism so with viruses humans have a bunch of old viruses oh yeah in our dna which is wild to think about it's so cool yeah those are evolutionary holdovers a lot of the time, I think. So I don't know if they've been incorporated recently, but probably way back in evolutionary time,

whatever our ancestor was, was infected by a virus and viruses can't replicate without co-opting a host's genome. So they integrate some of their genome inside. And if that is in a gamete, so like a sperm or an egg cell, that gets passed on to the next generation

usually it kills the cell but like if it happens to not kill the cell and if it happens to be in a gamete then it's like you got new dna friend you're the winner and so so that's how viruses work so viruses are like a separate class of thing and they can insert the genetic material. But bacteria can do this thing called horizontal gene transfer. And so if you think of a parent having a child, that's vertical gene transfer where you're passing it down through generations. And so horizontal gene transfer is passing genetic information within a generation. If you have a bacterium that somehow came up with a mutation that lent it antibiotic resistance, so when you spray it with an antibiotic, it doesn't die, then it could hypothetically, using horizontal gene transfer mechanisms, pass that gene on

to a buddy and just be like, hey, friend, here's this gene that will protect you from the antibiotic. Now we can all survive together. There you go, Jerry. Good luck. So, yeah. So, horizontal gene transfer happens and has happened in the past. And with tardigrades, they're still like a relatively small and more simpler organism. And so, it seems more…

There are single-celled organisms bigger than tardigrades yeah and so it seems more likely that they would be influenced by horizontal gene transfer but a big source of contention is whether that happens in animals like humans that are more complex because it would mean our whole idea of evolution is wild like we have tons of gut bacteria in us are those bacteria giving us genes and inserting genes into our somatic cells and our stomach lining and it's starting to be it's like literally who knows like we actually don't know yeah i vote yes just because that would be awesome i'm sorry we've determined it if you want to ask the science couch your questions you can follow us on twitter

at scishow tangents where we will tweet out the topics from upcoming episodes every week. Thank you to Geekly Unique, Patty Masha, and everyone else who tweeted us your questions this week. And now I have for you our final Hank Buck scores. Sari, you have two. Trace, you have two. Sam, you have one. Stefan is this week's winner with three Hank Bucks.

I did it! Congratulations, Stefan. Thank you so much. If you like this show and you want to help us out, it's really easy to do that. You can leave us a review wherever you listen. That is very helpful and lets us know what you like about the show. You can tweet out your favorite moments from the episode, which we always love to see. And finally, if you want to show your love for Tangents, you can just tell people about us. Thank you for joining us.

I have been Hank Green. I've been Sari Reilly. I've been Stefan Chin. I've been Sam Schultz. I've been Trace Dominguez. You can find Trace at youtube.com slash Trace Dominguez

where he makes Uno Dos of Trace. SciShow Tangents is a co-production of Complexly and WNYC Studios. It's created by all of us and produced by

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without our patrons on Patreon. Thank you so much and remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. Calipagi sheep are a type of sheep with a mutation that makes the sheep amass muscle around their butts instead of fat, resulting in the sheep with extra super big muscly butts. The first known Calipagi sheep was a ram named Solid Gold. And all of his descendants have big muscly butts

also calipagi is the greek word for beautiful buttocks gotta have one of those