Stuff You Should Know - Short Stuff: Genetic Mutations

Episode Date: May 28, 2025

All sorts of exotic and often terrible stuff runs through our heads when we think of genetic mutations, but the vast majority of them are caught before they happen thanks to the crack teams replicating our DNA in our cells.See omnystudio.com/listener for privacy information.

You're listening to an iHeart podcast. Are there any pictures of you online? Then you could already be in a massive police database without even knowing it. Clearview scrapes together images from Facebook, from LinkedIn, from Venmo accounts. I'm Dexter Thomas, host of Kill Switch, a podcast about how living in the future is affecting us right now. Police, they are trusting the software with this magical ability to lead them to the right suspect.

In this episode, we dive into how cops are using AI and facial recognition and sometimes getting it wrong and putting innocent people behind bars. So if your accuser is this algorithm, but you're not even being told that it was used, let alone given any of the details about how it works. Listen to Killswitch on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Hey, and welcome to The Short Stuff. I'm Josh, and there's Chuck, and this is Short Stuff, the mysteries of genetic mutations edition. That's right, because we're going gonna talk about the X-Men. Yeah, a mutation. I mean, I don't know if it would help you join the X-Men,

but there are mutations that alter people, sometimes in positive ways. We usually associate it with negative stuff, like a congenital disease or something. A lot of them are neutral. I think actually the vast majority are neutral. They don't really have any noticeable effect. Some are beneficial, lactose intolerance, immunity to malaria, when someone's vestigial tail turns into a glorious full tail. Those are all beneficial genetic mutations.

But all of them share something in common, and that is that the replication of the person's genome had some sort of error while it was being copied. Is lactose intolerance a beneficial mutation? No, lactose tolerance. I think you, I thought you said intolerance. Oh, I'm sorry, yeah, so lactose intolerance is apparently the baseline, the default.

Lactose tolerance is from a genetic mutation. All right. Well, let's get into this. Let's talk about DNA or deoxyribonucleic acid, as we all like to call it. Such a great word. Around the campfire. That's a molecule that's going to carry genetic material, almost mutation, when you're developing as a future human. And structurally I think we've all

seen the, if you've seen Jurassic Park, you've seen what these double, this double helix looks like. It's a long molecule comprised of nucleotides and there's two strands to that coil that form the double helix that kind of wind around each other and that's what the DNA, the full DNA, what would you call it? Just molecule? Looks like? The genome? Yeah, the molecule, DNA is a molecule. And you said it man, it is long. Apparently if you stretched it out, it would be about two meters or six feet tall if you could figure out how to stretch it out.

It's amazing. And it's made of 3.1 billion base pairs of nucleotides, thymine, cytosine, guanine, and adenine. And adenine goes with thymine, and cytosine goes with guanine. And you put all that together just with those combinations, you have a galaxy of different code that's embedded into the DNA that serves as,

like it tells the rest of your body, each cell, what it's supposed to do and how to do it. And usually that has to do with expressing proteins. Yeah. And, you know, like you mentioned, as these cells divide and the DNA is making copies of itself, there might be errors here and there. And that's where those mutations come from. And the egg, if they're in the egg and sperm cells, those are going to be passed on to the next generation. So that's a genetic mutation that's going to carry on and cause disease or genetic disorders.

You can also have what's called a somatic mutation, and that only affects you. It's not inherited by your future kids. Right, exactly. So really the big problem is genes, like a gene not being replicated correctly. And a gene is just a stretch of nucleotide base pairs along your genome that together shows how to encode a protein. It's the instructions to how to do a specific thing. And again, it's just a segment along your DNA. And when that stuff gets copied, if there's any kind of error,

like say you match up an adenine to a cytosine, it's going to prevent that cellular process, that whatever the gene is telling the cell to do, to not be able to be performed correctly, hence a mutation. Yeah, and our cells are constantly copying themselves, either replacing old cells or damaged cells. And when that happens, when they're doing that copy, that double-stranded DNA is going to split into the two parts, and each strand is copied on its own, and then they come back

together. And when that happens, there can be errors. The good news is it's approximately one in every 100 million replications this happens. So, that's a pretty good statistic to have in your hip pocket. The other good news is DNA knows what it's doing. So, it generally knows when an error happens, and they try to and often can repair and correct that before any problems arise. Yes. I think that's a pretty good place to take a break, Chuck. So let's take a break, Chuck.

Let's do it. Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Chuck, Have you ever thought about going voiceover? I'm Hope Woodard, a comedian, creator, and seeker of male validation. To most people, I'm the girl behind voiceover, the movement that exploded in 2024. Voiceover is about understanding yourself outside of sex and relationships. It's more than personal. It's political, it's societal, and at times, it's far from what I originally intended it to be. These days, I'm interested in expanding what it means to be VoiceOver, to make it customizable for anyone who feels the need to explore their relationship to relationships.

I'm talking to a lot of people who will help us think about how we love each other. It's a very, very normal experience to have times where a relationship is prioritizing other parts of that relationship that are being naked together. How we love our family. I've spent a lifetime trying to get my mother to love me, but the price is too high. And how we love ourselves. Singleness is not a waiting room. You are actually at the party right now. Let me hear it.

Yes. Listen to VoiceOver on the iHeartRadio app, Apple Podcasts, or wherever you about our podcast. Hi, I'm Daniel. I'm a particle physicist and I think our universe is absolutely extraordinary. Hello, I'm Kelly Wienersmith. I study parasites along with nature's other creepy crawlies and there's just endless things about this universe that I find fascinating. All right, well basically we're both nerds. We love learning about this extraordinary universe and we love sharing what we've learned.

So that's what we're going to do. And on our podcast, Daniel and Kelly's extraordinary universe is all about the mind blowing discoveries we've made about this crazy, beautiful cosmos. From the tiniest particles to the biggest blue whales. Each Tuesday and Thursday, we take an hour long dive into some science topic, during which time I try to suppress my biologist training and keep the poop jokes to a minimum. Learn all about our amazing and beautiful universe on Daniel and Kelly's Extraordinary Universe

every Tuesday and Thursday on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Learning stuff is fun with Josh and Chuck. Stuff is shut down. Okay, so there's basically two ways that you can, that a genetic mutation can develop. The cell replication, which we've talked a lot about, and then environmental influences. And there's actually different ways that can happen even during cell replication. There's tautomeric shifts, which is where the nucleotide itself undergoes a quick chemical reaction to where suddenly adenine turns into, I don't know, silver, just for a second, and

then it eventually turns back. But if that adenine nucleotide is being copied at that moment, you're gonna have a silver nucleotide in your DNA and silver just don't work when it comes to making proteins. Yeah, so that's sort of due to bad timing. Another thing that can happen as far as those errors go is it's called mispairing.

And was this the How Stuff Works article? Yes, it was. Yeah, they did a pretty good job of putting this in terms we could understand. If you imagine those two DNA strands that work together or zip together like a zipper, sometimes that zipper doesn't align. Your penis gets stuck in it? Oh, my God. And that can happen when the DNA is getting zipped back up

and that can cause parts of it to be skipped over or maybe something added that shouldn't be. Right. And then the third way that a mutation can happen during replication is what's called jumping genes, cousins of jumping jacks. And that is where, so these genes are normally, I don't understand this fully, but genes,

which again are just stretches of code on your DNA, can actually move. They can change positions, they can change places. Sometimes they replicate themselves and the replicant goes and embeds itself in another segment of your DNA. And if it does so in a gene, another gene, then it's going to mess up that gene's ability to perform its function.

I did not know that that was a thing. Did not either. Had never heard of jumping genes. I've heard of jumping beans and jumping jacks, but never jumping genes. Very nice. So that's the ways that can happen as far as like an error occurring in your body on a cellular level. You mentioned external factors. One of the big ones, and I didn't know to this extent even, is radiation. And you might be thinking like, yeah, so you just don't get x-rayed when you're pregnant.

Like that solves everything, right? That's not necessarily the case because UV radiation can be a very big cause of mutations, specifically when it's called like a sunburn on your DNA. If you have too much UV radiation, they can form something called, how would you say that? I'm gonna say pyrimidine dimers. Pyrimidine dimers? And I looked, I was like, is that a misprint?

Is it supposed to be dimmers? And nope. No, it's dimers. And especially thymine dimers that can distort that DNA structure. And that's sort of like a sunburn on the DNA. And that happens when a couple of DNA building blocks are stuck together,

and that's oftentimes caused from sun exposure. Yeah. There's also chemical factors too, which are basically biological or environmental factors. Essentially what it is is there's different kinds of chemicals that can make their way into the DNA in the nucleus of a cell and just mess with it. Sometimes they mimic nucleotides and they get pulled in like just some guy walking down the

street getting pulled into the Jimmy Fallon late night show because they couldn't get enough people to fill seats. That can happen during DNA reproduction replication and when that nucleotide that didn't mean to be there gets entered into the new code of DNA, again, problems arise. That's mutation. The problems arise when they have to sit there and watch Jimmy Fallon. Oh, man. Oh, boy. I'm going to hear it.

There are also biological factors like a virus can cause, that can get in the DNA and that can lead to mutations. And then there's some other environmental stuff as well, right? Yeah. Deanimating agents, they actually remove parts of our DNA. Substances like stuff found in cigarette smoke can stick to DNA like so much tar and change the shape of the DNA. Essentially, you don't want anything going anywhere near your DNA.

And if there's something that happens and it happens on an important gene, that mutation is going to produce some sort of problems down the line. But our body is actually really, really good at either preventing these errors or correcting them when it finds them, which is just mind-boggling to me. Yeah, it's super cool that our body can do this. Sometimes it's called a direct fix, and these are just small little errors. They likened it to a road crack, and they also likened it to just a quick patch on that road. The cell just directly fixes it, super quick like.

Yeah, and we should say the cell, the cell that's transcribing the DNA is aware of it because there are different molecules that proofread the newly created DNA to make sure it matches the original. That's amazing. Yeah, it is. So if they find a mismatch, if they find just some stretch, it could be big, small, whatever, they'll actually cut it out, excision, they'll digest it, and then they'll reproduce the correct

version of it and then connect it to that part that they cut out of the DNA and then zip it together. And if it's, if a whole section of DNA gets damaged, they can go to another DNA strand and say, hey, I'm glad you're here because we're going to use you now to come fix this other strand. Yeah. Thank God you're here. They were about to pull us into Jimmy Fallon and we needed something to do.

That's an offset thing in my house. Thank God I was here because I know we mentioned War of the Roses, the movie, how it holds up. That's one of the great lines from War of the Roses when they are separated but Michael Douglas is still in the house and the Christmas tree catches fire and he runs downstairs and puts it out and screams, thank God I was here. And I say that a lot and just whenever anything dumb happens that I saw for the family, I go, thank God I was here. And I say that a lot and just whenever anything dumb happens that I saw for the family, I go, thank God I was here.

That's great, that's a great thing. Man, Chuck, everybody loves Chuck. For reasons like that. Not everybody, just like Raymond. All those people can go soak their heads. Oh, okay, thank you. Well, since I think we're out of stuff to talk about, short stuff is out.