SciShow Tangents - DNA with Amanda Wacker

Episode Date: May 25, 2021

This week, we’re joined by scientist and podcaster Amanda Wacker to talk about DNA, the building blocks of life! A blueprint for building a living thing, even!Webster’s dictionary defines DNA as ���any of various nucleic acids that are usually the molecular basis of heredity, are constructed of a double helix held together by hydrogen bonds.” I define it as the little wiggly guys inside us that make our cells and stuff. We’re both right, in our own way.If you want more Amanda Wacker, check out her podcast, Triplicates! And check her out on Twitter: @AstroAma!Head to the link below to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter! https://www.patreon.com/SciShowTangentsA big thank you to Patreon subscriber Eclectic Bunny for helping to make the show possible!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links:[Ask the Science Couch]Gene expression & cell typehttps://www.cirm.ca.gov/our-progress/advanced-how-does-stem-cell-%E2%80%9Cknow%E2%80%9D-what-becomehttps://www.ncbi.nlm.nih.gov/books/NBK26885/https://www.cell.com/trends/cell-biology/fulltext/S0962-8924(20)30059-3https://www.discovermagazine.com/health/our-cells-are-filled-with-junk-dna-heres-why-we-need-ithttps://www.nature.com/articles/d41586-018-05462-w[Butt One More Thing]Pooprintshttps://www.cnbc.com/2018/12/19/pooprints-brings-in-millions-testing-dog-poop-dna-to-snag-non-scoopers.html

Hello and welcome to SciShow Tangents, the likely competitive knowledge showcase. I'm your host, Hank Green, and joining me this week, as always, is science expert, Sari Reilly. Hello. And our resident everyman, Sam Schultz. Hello. But in addition to those two people, we have a different person joining us this week as our special guest, science communicator and host of the podcast, Triplicates. It's Amanda Wacker. Hi. Hi. Thank you so much for being here. I was on a podcast with you once, and you told me a story that I want you to tell again that involved space and guns and bacteria, I think. Yes. Everyone's favorite microbe, Bacillus subtilis.

Ah, yes. The good old, the good old, soily, poopy microbe. Yes. I think you had an equally interesting camel poop fact about bacillus subtilis. But my bacillus subtilis fact was having to do with how survivable they are to being directly impacted against a solid surface. So these people took single Bacillus subtilis spores, shot them at a wall, and they were like, they can survive for up to 299 plus or minus 18 meters per second, which I don't have a reference for that, but that seems really fast. Yeah. Yeah.

I mean, if I was going 300 meters per second, I would definitely not want to smack into a wall. I can tell you that. Yes, and they can survive. They're fine. So, and then the question becomes, my thought was like, okay, like, in what circumstance would we care? Then I was like, okay, well, what if, like, Abyssalosotilospora is, like, out there in the universe, and then it, like, like goes and gets into a planet and that's how life gets from one place to another. Is that the idea of the research or are they just messing around? They were not just messing around with our federally funded research money. So a lot of people are interested in Bacillus subtilis.

It's actually a microbe that is found within like the clean rooms where nasa jpl like the where they make all the hardware that they send out into space so they were trying to see if it would survive the impact velocity of it hitting like the moon or like anything really and then right right other space things there's a lot of space debris if you guys are up on game on the space debris crisis we have, it's not great. So they just want to know in case there's stuff up there, they want to see what kind of situations it can survive. Yeah. And they actually wrote a paper about this lunar microbial survival model, taking in all the accounts of the UV rays and if it could survive the impact velocity and like the temperature, something would hit the moon at and all this stuff. And that's like where these numbers really played an important role in creating this lunar microbial survival model.

Oh, man, it's hard enough to survive just being still on planet Earth, let alone. For you, maybe. For other guys. Yeah other guys it's no problem being a spore sounds pretty easy comparatively don't have to make a lot of decisions just follow the gradients and uh hope you don't get fired out of a gun into a wall at above 300 yeah at 301 meters you're in trouble but but until then so we have a podcast for you. We do this every week. It is our science trivia podcast where we try to amaze and delight and one-up each other with science facts.

And we also try to stay on topic. And we play for glory, but we also play for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of you will be crowned the winner. Now, as always, we're going to introduce this week's topic with the traditional science poem. This week it's from me. And I'm going to go ahead and preface this poem by saying,

maybe it should be a postscript, I don't know, by saying it was a busy day that had more, it included more activities than I had anticipated. And so, here's my poem. Okay. There once was a molecule placid. No. Who did more than ever my ass did.

A huge molecule that makes you you. Deoxy-ribonucleic acid. That was your whole poem? Wonderful. You are in trouble. Is it one molecule though? I mean, deoxy-ribonucleic acid is a molecule, but our genome is not stored in one molecule.

It is a great molecule, and it is the molecule that contains our genetic information, along, I guess, with some RNA, maybe. And also, there's epigenetics now, which didn't exist when I was in school, basically. So I don't know anything about it. Sari, what is DNA? Well, after that banger of a poem, I don't know why I even tried. Can't just gloss over that, Hank.

Yeah, I think you got the heart of DNA right in that it is the hereditary material in life as we know it, pretty much. Asterisk. So like humans and most other organisms that we consider to be alive use DNA to pass down their genetic information from one generation to the next. And the DNA molecules in cells is what allows an organism to make all the RNA and all the proteins that determine cell function and determine their body makeup and like help them do anything, especially stay alive, which is an exceptionally hard task. Oftentimes, Amanda, on this podcast, we have a hard time defining things. But in this case, it's a molecule. Yes, there is a definition.

It has a chemical formula and a structure. We know exactly what DNA is. Amanda, you do like DNA origami is what you told me. What does that mean? Okay, so DNA origami is super dope. They basically take a viral genome, which is single-stranded DNA. Our DNA is double-stranded, so we just get one, one strand, and it's a circle. And if you could imagine, I have a hair tie. If you can imagine just like pressing two ends that are not right next to each other kind of close and then just keep folding it, you can like create these shapes.

So that's what we do. And we use it as a tool to study enzymes that interact with DNA. So it's not like I don't just like make DNA and then it's just like pretty like we use it to discover more about, you know, molecules and things like that. So that's what I am working on now and we'll be doing for the next five years, I guess. But is it pretty, though? It is. I think it's really cool. And my my like tester project, because it's like a brand new lab. So we have to like set up everything and try everything and make sure everything works in our own hands with our new machines or whatever. My first DNA origami is a 2D heart made out of DNA, which is super cool.

It's going to be so cute. Okay, that's great. I can post pictures when it comes out, but yeah. What do you use to manipulate the pieces of DNA? Little tweezers. No. Okay, so DNA has a sequence, and it's like A goes with T, and that's how it goes, right? Like it's all the letters have a match.

Because it's single-stranded, you can put another strand next to it. So we get these tiny strands and we basically make half of it align with one part of the genome and half of it aligned to a different part of the genome so that this part will connect to one part of the genome and then the other half will connect somewhere over there. And then it has this, because it's like connected to, we call them staples, it'll like bring these two parts of the genome closer together. And then you just do a bunch of those. Like my heart has like 200 something staples. And then the way you get it to connect is just you take it through a heat ramp. So you start the temperature really high, which melts the DNA. So it's like not together. And then you slowly bring the temperature lower. And as you go through the lower stages of the temperature, it comes together because it wants to, because it's a chemical molecule and that's preferential and then boom you got a 2d heart shape that you can look under an atomic

force microscope and of course you've just got an atomic force microscope lying around so that you can look at your heart we made our own like that sounds really just with just a shoe box and some rubber bands all right. All right. So that is what DNA is. I'm not going to make you tell us the etymology of DNA because it's deoxyribonucleic acid. Thank you.

It's a nucleic acid with... Deoxyribose? Two riboses. With deoxyribose. And that means that it's time for the quiz portion of our show. And I'm excited to introduce you to our game. It's called Brainstorm. The rules

are simple. Are they simple? I don't know yet. Basically, I'm going to ask you three questions, and then we're going to start. A different person will start every time. Every one of these questions has several different answers. And so I'm going to ask the question, and then we're going to go, and a different person is going to start every time. If you cannot get the question correct, then we'll see if your successors can get one of the answers correct. And then we will see what happens at the end of the process. So let's begin with round number one. Now, scientists have been learning to sequence DNA for a long time. We're getting better at it all the time. But when we started out, we started with some single-celled organisms

like Haemophilus influenza, which is a bacteria. That was in 1995. And we've gotten better and more clever methods allowing us to sequence animals. You're going to have to tell me, in order, one of the six first animals to have their genomes sequenced. We will start with Amanda and then sari and then sam and we'll go until someone gets it wrong is the goal amanda do you have one what counts as an

animal oh no it's a multi-celled organism it doesn't yeah so a multi-cellular organism i want to say they like did yeast first yeast first because yeast are very central to things. But I don't know entirely. That's not an animal. Exactly. I'm not going to let you get away with a yeast as an animal. Yeah, that's what I feel like. No, give me an animal.

A chicken. Nope. Okay. Can anyone come in and stomp Amanda or will you all get it wrong? Sari, what do you have? A mouse. A mouse is probably on this list. I hope so.

I don't know. It is on this list. It is. It is. It's like lab animals. I only know a few. Okay. Sam?

Fruit fly. Fruit fly is correct. Of course, fruit fly was an early one. Amanda, you can re-enter with the correct answer now. I'm making up the rules as I go along. Okay, thank you. I'm making up the rules as I go along. Okay, thank you. I'm going to go Sea Elegance. Sea Elegance was the first one.

Wow. I am so good at this. Wow. She's back, everybody. Sari. A zebrafish? That's a great guess. Very common organism, but not in the first six.

Sam? Gulp. I don't know any more animals. A, what's in, a rat. That's great, but no, that's incorrect. And somehow, because I've changed the game up, Amanda ended up winning that one. That's great.

The fact that you got the first one wrong. And we both got the same amount of them right fantastic uh so the ones that you missed were human oh mosquito and for some reason the japanese puffer fish was the sixth one cool not what i had expected at all all right now we're going to start with Sari and then Sam and then Amanda with our second round on ancient DNA. The study of ancient DNA has allowed researchers to learn more about extinct animals, whether that's their physiology or their phylogenetic relationships or just something else. These studies have benefited from the massive improvements in sequencing technology that

allow us to know what are in those ancient pieces of DNA. But it's also been important to be able to find new sources of ancient DNA. Now, one of the most common sources in the beginning were skeletal remains. You find the skeleton of an organism and then you're like, let's scrape some DNA off and see if we can find some genome stuff. But we've put their creativity to the test, and scientists have found four more sources of ancient DNA that are not skeletal. Sari, can you go first? Tell me a source of ancient DNA.

Pine tar resin. Pine tar resin. Sounds like you know what you're talking about, but it's not on my list. Yeah! There's someone who chewed it as gum and then they found DNA in it. That's fine. Oh, yeah, yeah, yeah. I remember that.

I guess we're thinking more ancient than that and not just. Oh, okay. That is true. Yeah, that was that gum. R.I.P. It was that gum. Maybe I should let you have it because that's right. Yeah.

It's up to you. I'm going to let you have it. It's right. Okay, Sam. Thank you.'m going to let you have it. It's right. Okay, Sam. I didn't entirely understand the question. Poop? Poop is correct. Yes.

That was going to be my answer. The answer is always poop. Yeah. That's a pretty safe one. Poop and fruit flies. Amanda, I can give you a hint. What else comes out the butt? I'm not entirely sure. what else does come out the butt

well i guess i'm not talking i'm talking about reptiles i'm talking about reptiles and birds and stuff because they only have that way yeah eggs do eggs come out of reptiles but they come up the cloaca yeah they have an all-purpose hole. I'm shook right now. Wow. So is this like any ancient DNA, not just human DNA? Oh, yeah, yeah, yeah, yeah, yeah, yeah. I was like, human eggs? That's where we got ancient DNA? That came out the butt. Yeah.

Okay. What else is there? What else do we look? It's gotten hard. There are not many left and they are both weird vomit that's great that's great that's a that's a winner but that is not known as as far as my sources can confirm no one has pulled pulled dna out of vomit yeah sam is it what like boogers i don't know boogers is a great guess but also incorrect amanda i think amanda you

were the last one to get a correct answer. So it's coming back around to you again. And so it doesn't even matter if you get it right. You're winning anyway. It's a lot of pressure. I know what LeBron feels like. I am going to go with fur. Oh, that was amazing.

Yes, that is correct. The only one y'all missed was soil, because they can just, in areas where they think a lot of things were living, they can just pull some soil out and do DNA tests on the dirt, which is wild and very exciting. But yes, correct.

Hair was one of them. It's a great source of DNA because it's relatively easy to get rid of microbial contamination, and DNA has been extracted from hair that's over 4,000 years old. So that's a winner. All right, we have our final round here. This is probably the hardest one, unless you remember more about Gregor Mendel than I did.

In 1865, Gregor Mendel published the results of his experiments in plant hybridization. He documented the passing of traits between generations of pea plants. And while his results were published quietly and with little fanfare, the conclusions that he drew about inheritance would end up being foundational for the field of genetics. In his paper, Experiments on Plant Hybridization, Mendel documented the passage of seven traits in his pea plants, which related to the seed, the pod, the flowers, and the stem. Can you tell me one of the seven traits? And I believe now we're starting with Sam.

Was it like flower color, one of them? There's yellow ones and white ones. Flower color is not one of them. What the hell? Oh, weird. It's your word choice. I think seed color is a thing. Yes.

Color of the outside of the seed, white versus gray. Oh, wait. No, Sam was also right. Yeah, okay. Color of flower is also in there. It was just poorly structured in the list. Congrats, Sam.

Thank you. You're still in it, Sam. This is me pulling on the archives. It's whether the seed or the pea is smooth or wrinkly, one of them. Oh, yeah. Yes, shape of the ripe seed round versus angular versus wrinkled. Yeah. Trying to picture that little chart in the science book.

Was it like number of seeds per pod? No, Sam, I'm afraid that you are out. You are out. You are out again. Plant height. Yes, the length of the stem. There was the short ones that were up to 1.5 feet and the long ones that were up to seven feet. Don't remember the correct terms,

but like flower placement, whether they like grow out the sides or grow out the top. Jeez, it is a battle of the science experts. Position of the flowers is another of the traits. I too am trying to think of the little biology 101. Short, short, tall, yellow, white, you know? Yeah, exactly. Drawing my pun at squares.

I am very scared right now. And if I say it wrong i'm out no that's correct but you've won the other two so though so yeah i know but i want to be three for three i'm gonna go with number of petals number of petals is a good answer, but a wrong answer. Rip. Sari, you pulled one out at the end there. Do you have any more that you can remember? You got more Mendel in your brain? So my next guess, if Amanda got it right, was going to be pod shape.

Yes, pod shape is one of them, as is the color of the unripe pods. I did not know that one. And the other one that you missed was the color of the unripe pods. I did not know that one. And the other one that you missed was the color of the inside of the seed. Fantastic work, everybody. That was a lot of fun. And including Sam, you also did well. I tried my best.

And now it's time to take a short break and then it will be time for Truth or Fail. I've prepared three science facts about DNA, but only one of those facts is real. The other ones are big ol' stinkin' lies. You guys have to figure out either by deduction or a wild guess which is the true fact. If you do, you get a Hank Buck. If you get it wrong, then you don't. So, DNA. We all know it encodes biological information, and it does so using chemistry. A base pair of DNA is made up of a phosphate, a sugar, and one of four nitrogenous bases that defines its sequence.

And all that means that in addition to being an incredibly powerful biological molecule that can store a tremendous amount of information, DNA has chemical properties that make it potentially useful to make other materials for humans. The following are three applications for using DNA as a building material, but two of them are fake. Which one is the real one? Number one, because of the way that DNA cross-links, it forms a natural hydrogel that can serve as a scaffold to hold enzymes. So scientists used DNA to create a flexible contact lens with self-cleaning enzymes packaged inside. Fact number two. The chemistry of DNA makes the molecule swell up when heated, making it a useful protector against fire when applied to another surface.

So researchers have treated cotton with DNA to turn it into a flame-retardant fabric. Or fact number three. DNA is a transparent dielectric, meaning it can be used as a screen without worrying that it will conduct electricity, and it's been used in thin films to increase the luminance of organic light-emitting diodes, including in the construction of televisions. Which one of them is it? You got fact number one, a contact lens with self-cleaning enzymes packaged inside, flame-resistant cotton, or it's used in the construction of televisions. Any thoughts? Ask me questions. Quiz me. Amanda, you didn't do one of these, right? You haven't worked on any of these projects? No. One of them sounds familiar, but I just hadn't

heard it applied in that way. So that makes me tense. Yeah. Well, the thing about truth or fail is they are often based on true facts. So it almost hurts when you know more. Why don't we let the others? Okay. Yeah, yeah, yeah. Also, you don't want to lead off with, I'm pretty sure, me, expert in the topic, it's this one. Yeah. Because then you're going to have a bunch of tagalongs. I have a question. For any of these, do you know where they isolated the DNA from?

Or did they just like create random strands and then were like, let's apply them? Because it seems like you get it from an organism or like Amanda was describing with the origami, you can like create a sequence intentionally. So my guess is, and I don't know the answer to this question, it's pretty easy to isolate DNA from a bunch of cells. And we have plenty of cells to work with. There's lots of meat in the world that is not hard to get. So my guess is that we isolated the DNA from probably just a bunch of chicken breasts. Is DNA delicate? Like surprisingly, like I always sort of pictured it as such, but surprisingly not.

Like you can kind of, it's like a slimy, you can pick it up. It's a polymer. Not like as strong as like nylon or something, but it's a, you know, it can sort of hold its own weight at least. Okay. So I'm going to be blown apart by whatever blasts out of a TV. How do TVs work? Does that work? Lasers into your eyes.

Sam's just picturing like TV is just like Jerry Seinfeld being shot out of a wire at you. Well, maybe like in the 50s, that's what it was. Yeah. No, it's actually a lot of very tiny Jerry Seinfelds. Climbing right in my brain and making me laugh. Thanks, Jerry. Doesn't seem like it would be good

for a long-lasting consumer product like a TV, but... That's a good point. I know nothing. That you maybe don't want to hit DNA with a bunch of photons because we do know that being hit by photons

does hurt DNA. That is well-known. Are you leading them to an answer? No, I'm just saying. I like to be a part of the conversation. And trick us. And at this point, I've forgotten which one is the true fact.

The flame retardant fabric one sounds like something I've heard before in a different context. So I think I'm going to go with contact lenses. Okay, weird DNA-based contact lenses. I'm going to go with the fabric just because it sounds the most feasible. I don't know. If I was going to coat something, I'd try fabric before sticking something in my eye or putting it on a TV. So that's my guess.

I am going contact lenses. Okay. Contact lenses. Very confident. Yeah. Very confident. Despite its incorrectness. Oh, no.

So the true fact was Sariiley with the flame retarded cotton so dna is intumescent which is a great word which means that it swells up when it's heated and these intumescent properties are a result of its combined phosphate nitrogen and sugar which when burned create a buildup of carbon foam that resists burning. The researchers coated cotton with DNA obtained from herring sperm, so it wasn't chicken breasts, it was herring sperm, and then burned the DNA-coated fabric with methane flame, only to find that the fire did not catch.

But as for the contact lens, that was inspired by a real thing, a bio battery that uses DNA hydrogels, which are a real thing to hold enzymes that catalyze reactions in the battery to make fuel. So you probably had heard about DNA hydrogels and you were like, that sounds right. Yeah. Sorry. Yeah, it's OK. And DNA has been used to increase the luminance of organic light emitting diodes. So that is a real thing. But there has been no TV that has used it, probably because it breaks down too fast. Though I don't know.

It may be able to make a DNA polymer that is a little more long lasting. Yeah, maybe you just invented the idea. I feel like it's probably the direction they were going down when they started doing the research. It's amazing the amount of research that goes into like making better TVs. And I'm like, could we like focus on, I don't know, anything else?

Capitalism. Yeah, we gotta have a better phone, Hank. I'm like, you know what I want is one where I can pick out this old battery and put in a new one.

They're like, oh, I'm sorry, that technology doesn't exist. It's not possible. That leads us to the final scores. And Amanda and Sari have come out in a tie game.

Congratulations to the both of you. You are winners today. And you know what really that means? The most important thing is that Sam lost. Why? What did I ever do? It's ever since you brought up, like, I don't feel like I made fun of you until you brought it up. And now I feel like I can't stop. Like, it's ever since you brought up like i don't feel like i made fun of you until you brought it up

and now i feel like i can't stop like it's part of the shtick of the show you always were you just didn't notice it okay well at least now i know so congratulations to the two of you and now it is time to ask the science couch where we've got a question for our couch of finely honed scientific minds this week is well populated it is from at Airby Dragons who asks, why does your foot know it's a foot if all the cells contain the same DNA? I'm so glad that I can just now say Hawks genes and then be quiet. So the reason your foot knows it's a foot and how it maintains being a foot throughout your life is what Hank alluded to in the beginning, which is epigenetics, which didn't exist.

We didn't know the answer to that question. We still don't entirely know the answer to this question, just for clarity. Yes. But basically, every cell has all the same DNA. But what happens is through the process of the cells deciding, OK, I'm going to be a foot, all these other genes turn on and some genes turn off and like they use histones and whatever, but basically some sections of the genome get tied up so that the proteins in that genome don't make themselves

so that you don't get like things that see color in your foot. They're like, no, we don't need that here. So they get tied up and basically put in in storage and then that's why your foot knows it's a foot and your skin knows it's skin and your muscles know it's muscle is that different parts of the genome get turned on and off through the process of differentiation and that's so you so you're saying like it's literally the histone is like this just like imagine a ball and the ball like binds up a bunch of DNA because everything's balls. If you listen to our patron-only podcast, you'll know about how it's all just balls. And it literally prevents those genes from being encoded by bunching them up to a place where ribosomes can't reach them.

So it's like a physical process of turning them off by making them inaccessible to the protein coding machinery of the cell. Yeah. And there are other things too, like if you've heard the term DNA methylation, that's like adding methyl groups to make the DNA more like chunky also to physically block binding. But there are also a bunch of small proteins and mRNA strands, I think, called transcription factors that can bind to DNA. And those are a little bit more svelte. They can still block, but they can also activate DNA. And so like in addition to blocking certain areas, if you have an eye cell, for example, then there might be a

transcription factor that bonds to a part of DNA that codes for rod and cone cells. And it's like, make more of these. We need these. Right. And like flagging that down. Make lots and lots of this. To specialize. I mean, do you ever feel like you're just a big pile of cells?

Oh, every day. Yes. Oh, God. It's very, very weird. The two of you, yes. Everyone else listening is like, no. I don't. You know, what's really amazing is that all of our cells work together.

Like there's a, there's like trillions of them. And they're like, you know what we should do? We should like be very, we should very carefully work together to have this like whole system function. And then sometimes one of your ear cells decides, you know what? What if I grew a really long hair? And then you have to be that person now that shaves his ears

all the time because he turned 40. You just have a bunch of ear hairs. If you want to ask the Science Couch your question about your ear hairs,

you can follow us on Twitter at SciShow Tangents where we'll tweet out the topics for upcoming episodes every week. Thank you to at Sneffin, at SalaciousScribe, and everybody else who tweeted us

your questions for this episode. If you want more Amanda Wacker, and after being delighted so tremendously in this episode, why wouldn't you? You can check out the podcast Triplicates wherever you get your podcasts. Amanda, what is Triplicates? Triplicates started as me and two of my friends starting a PhD program and not knowing what we were doing.

We were like, whoa, probably a lot of people don't know what we're doing. Let's kind of make like Ned's Declassified School Survival Guide, but like for grad school programs. And like that's the whole thing. We come, we talk, we're like, this is what's going on. Sometimes we don't know what's going on. So we bring on guests who do know what's going on and then they explain to like, this is what's going on. Sometimes we don't know what's going on. So we bring on guests who do know what's going on. And then they explain to us, this is how you do things. And then we share that information with everybody else so they can know what's going on too.

And you can find us, as Hank said, on most streaming platforms. You can also find us on social media platforms at TriplicatesPod if you want to follow us there. And then if you want to follow me, I'm mostly active on Twitter at Astro Ama, A-M-A. Nice. Thank you so much, Amanda. It's been a pleasure to have you on the show. If you like what we do here and you want to help us out at SciShow Tangents,

you can do that by going to patreon.com slash SciShow Tangents, where you can become a patron. But if you can't support us on Patreon, you can also leave us a review wherever you listen. That helps us know what you like about the show and also helps other people know what you like about the show. And finally, if you want to show your love for SciShow Tangents, just tell people about us.

Thank you for joining us. I've been Hank Green. I've been Sari Reilly. I've been Sam Schultz. I've been Amanda Wacker. I always forget to tell people about that part. Yeah. Great job.

SciShow Tangents is created by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who edits a lot of these episodes. Our social media organizer is Paola Garcia Prieto. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Bedish. And we couldn't make any of this without our patrons on Patreon.

Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. but one more thing since 2011 american company biopet has offered a service called Pooprints to help put an end to the worst possible crime. Pet owners not cleaning up dog poop. Using a kit with specialized swab and preservatives, apartment complex managers can take samples from dubious dog doo and mail it to the company. The company analyzes the DNA and compares it to a database containing records of every registered pet to identify the culprit and allow managers to confront the pinpointed pooper. What? What?

Dog poop surveillance. Oh, my God. I like the idea that you don't have the individual DNA of the pet, but instead you just know what kind. Like, they tell you, it's like, this is a Pomeranian. And then you're like, got to, like, surveil all the Pomeranians in the apartment building extra closely. We've got to narrow down to either Shishi or Button. It's one of the two.