Genetic mutations can cause extraordinary biological anomalies in both animals and humans, ranging from rare conditions like polyphilia (two-headed organisms) and cyclopia (single central eye) to adaptive mutations like the DEC2 gene allowing reduced sleep needs or the myostatin mutation causing hypermuscularity. These mutations often result from developmental errors during embryonic stages, where cells fail to properly divide, separate, or differentiate. Environmental factors such as pollution, radiation, and parasitic infections can also disrupt normal development, causing deformities in fish, amphibians, and other species. The study of these mutations provides valuable insights into developmental biology, evolutionary adaptation, and potential medical applications, though many remain poorly understood and raise questions about the delicate balance of genetic regulation in living organisms.
Strange Genetic Mutations That Shocked Scientists
Added:A calf born with two fully working faces, a rattlesnake with two heads fighting over food, a fish that somehow grew two mouths, a cat with three eyes, frogs sprouting extra legs in a Minnesota pond, and more. These are disturbing mutations discovered in nature that terrified scientists. In February 2024, a farm in southwest Louisiana woke up to a very unusual birth. One of the cows at a farm called Buru Farms had given birth overnight to a calf with two faces. [music] From the ears back, the body looked normal, but the front of the head had four eyes, two noses, and two mouths. The owners [snorts] named the calf doo face.
[music] Two face. Cases like this are extremely rare. According to the farm, the odds of a birth like this are estimated to be around 1 in400 million.
Even more surprising, the calf was alive. That almost never [music] happens. Most animals born with this condition, known as polyphille, are still born or die just after birth. The calf couldn't stand on its own at first, though, so the farmers had to support it with a sling and bottlefeed it because it couldn't nurse normally from its mother. But both faces were actually functioning. The calf could breathe through both noses. The eyes reacted to light and movement. The two mouths even moved together, although one was slightly deformed. Unfortunately, as expected, it didn't live long. It died after just 26 days. In 2019, researchers surveying the Pine Barons in New Jersey came across something they almost never see in the wild. While checking a rattlesnake den, two researchers named Dave Schneider and Dave Burkett spotted a tiny newborn snake [music] moving through the leaves. When they picked it up, they realized it had two fully formed heads on a single body. Since both the guys were named Dave, the snake quickly got the nickname Double Dave.
The baby rattlesnake was only about 9 in long and just a few weeks old. This kind of mutation is called a besphille which happens when what should have been identical twins don't fully separate during early development. So the embryo develops two heads on one body.
Scientists say it's basically the reptile version of conjoined twins.
Animals like this almost never survive long in the wild. Each head has its own brain, [music] so they try to control the body at the same time. One head might want to move left while the other wants to go right. not the most efficient way to hunt or avoid predators. Not to mention, when it comes to actually eating, both heads may compete [music] for the same meal. So, Dave and Dave decided to bring Double Dave into captivity where it could be studied [music] and taken care of. In August 2019, a woman named Debbie Gettis was out fishing on Lake Champlain near the New York Vermont border when she hooked what felt like a pretty solid catch. At first, she just felt like it was a big trout. But when she finally pulled it into the boat, she immediately noticed this thing was not normal. It had two mouths, one above the other.
When we got it in the boat, I couldn't believe what I was seeing. Two mouths.
And this fish was healthy and thriving, Debbie said. Photos of the trout were shared online by a local fishing group called Naughty Boys Fishing. And within days, thousands of people were sharing it and arguing about what could have caused it. Some thought it might be a genetic defect that happened while the fish was developing. Others wondered if it might have started as an injury that healed in [music] a strange way. Even experienced fishermen who saw the photo said they'd never seen anything quite like it. Next up, we have a Guinness World Record setting cat or cats depending on how you look at it. Frank and Louie, or as some referred to them, Frank and Louie, which is kind of mean, but I also do kind of love that name. In 1999, a kitten was born in Massachusetts with an extremely rare condition called deprocipus, sometimes known as Janice [music] condition. Instead of having two separate heads, the kitten had two faces on a single head. He had two mouths, two noses, and three eyes. Most cases like this end with the animal dying within a few days. Because of that, the kitten was set to be euthanized. But one veterary nurse, Marty Stevens, decided to take the kitten home instead and see if she could keep him alive. She named one face Frank and the other Louie.
Keeping him alive took a lot of work at first. Stevens tubefed him until he was 3 months old because she was afraid he wouldn't [music] be able to eat. Even though he had two faces, the cat only had one brain and one esophagus, and [music] only one of the mouths actually worked for eating. The third eye in the center of his face didn't function and never blinked, so he looked like he was constantly staring. Kind of creepy. But Frank and Louis survived far longer than anyone expected. In 2012, Guinness World Records officially recognized him as the longest living Janis cat ever recorded.
He ended up living 15 years, about the normal lifespan [music] for a house cat.
In August 1995, a group of middle school students visited a small wetland near Henderson, Minnesota. As part of a school field trip, while catching frogs along the edge of the pond, they started noticing something strange. A large number of the frogs had serious deformities. Some were missing legs, others had extra ones. A few had limbs that were bent or growing out at odd angles. When scientists investigated the site, they found that half of the frogs in that pond showed some type of abnormality. That number was far higher than what biologists would normally expect to see in the wild. And that was unsettling. Being that frogs live partly in water and partly on land, they're often used by scientists as an early warning sign that something may be wrong in the environment. So, this set off a large investigation across Minnesota.
Researchers surveyed wetlands around the state, examined nearly 25,000 frogs from 195 different locations. They documented deformities, uh, like extra limbs, partially formed legs, missing feet, and abnormal bone growth. In some wetlands, more than 60% of frogs were affected.
One major cause scientists identified was a tiny parasitic worm called this.
The parasite infects tadpoles while their legs are still [music] forming.
And when that happens, it can mess up limb development, sometimes causing frogs to grow extra [music] legs or deformed ones. But researchers also found that parasites didn't explain every case. [music] And in some areas, the exact cause was unclear. Picture this, a goat walking down a dusty road on two legs like a person. That's exactly what villagers in Bahar, India saw in 2015. A baby goat was born missing its hind legs. Instead of struggling to survive, it did something incredible. It learned to balance upright on its front legs and walk.
Locals captured the goat on video and it quickly went viral. Veterinarians examined it and found no neurological issues. The goat's spine and muscles had simply adapted to its new reality.
Experts have documented animals adapting to missing limbs before, but what stunned scientists was how efficiently this goat moved. It walked with posture and rhythm almost identical to a human's gate. There was no training, no help, just raw survival instinct. Even now, researchers say they still don't fully understand how it achieved such perfect balance. In 2013, Spanish fishermen discovered something disturbing inside a pregnant blue shark. a fully formed two-headed embryo. Both heads had functional gills, eyes, and brains. This wasn't an isolated incident, either.
Similar two-headed shark embryos have been discovered in the Gulf of Mexico, Japan, and Argentina. Marine biologists confirmed the cases in studies published in Journal of Fish Biology. This condition happens when an embryo begins to split, but never fully separates.
It's rare in any species, but in sharks, it's exceptionally unusual. What puzzles scientists is why these cases have increased in the last decade. Some think pollution or environmental stress may play a role. Others say it might be genetic instability from population declines, but there is still no clear answer. The two-headed embryos usually don't survive long, but their increasing appearance is leaving experts uneasy. In 2017, biologists in Costa Rica documented something extraordinary. A frog whose entire body was see-through.
Transparent frogs known as glass frogs already exist in nature. But this one wasn't just translucent. It was completely clear. Its beating heart, stomach, and liver were fully visible through its skin. Genetic testing showed it didn't match any previously cataloged species. The frog wasn't sick or albino either. Researchers studied it carefully, but couldn't determine why or how. how the mutation happened.
Transparency like this gives no clear evolutionary advantage and had never been recorded at this level in a wild amphibian. The frog lived a normal lifespan and appeared healthy. But its mutation remains one of the most puzzling amphibian cases of the last decade. In 2017, a farmer in Assam, India, witnessed something he described as quote otherworldly. One of his goats gave birth to a baby with a single large eye positioned in the center of its forehead. kind of like that lady from Futurama. Veterinarians diagnosed the newborn with cyclopia, a rare congenital disorder caused by abnormal development of the front portion of the brain. The goat also had a missing nose and fused eyelids. What makes this case so mysterious is how well-developed the rest of the body was. In most animals, this condition is fatal early in development. But this goat was born alive and even survived for several days. Experts said the chances of this happening naturally are astronomically low. Photos and footage were verified by local veterary authorities and the case gained international scientific attention. For decades, people across the US have reported sightings of hairless creatures rumaging through trash or crossing backyards. Many assumed these were cryptids or mangy coyotes. In many cases, they were actually raccoons. [music] Sarcoptic mange can explain most of these sightings, but in several documented incidents in Pennsylvania and Texas, veterinarians found raccoons with no mites, no infection, and no disease.
Their hair just simply never grew. Their skin was unusually thick and sensitive, and genetic testing didn't reveal a single clear mutation. Environmental triggers have been suggested, but no one has pinned down the cause. The phenomenon has shown up in scattered, unrelated populations across the country. But what makes it so confusing?
It's not spreading like a disease. It's just appearing randomly again and again.
In 2017, a farmer in Georgia was stunned when one of his goats gave birth to a baby with eight fully formed legs.
Spider goat. Veterinarians confirmed the extra limbs were not just small growths.
They were actual legs attached at the torso in a way that suggested embryionic twinning. Usually when an embryo splits and doesn't separate completely, you get conjoined twins. But this goat had only one head and one set of organs. [music] That made its mutation unique. Despite its deformity, the goat lived for weeks after birth and became a media sensation. Scientists couldn't fully explain how the extra limbs formed so symmetrically or why its internal development stayed singular. It remains one of the strangest livestock cases ever documented. Right after the Fukushima nuclear disaster happened in 2011, a group of Japanese researchers led by a scientist named Joji Otaki decided to study some of the local wildlife. They wanted to see what effect the radiation was having. They picked a tiny super common insect called the pale grass blue butterfly. When they caught the first batch near the accident site, they noticed a few weird things right away. Some had dented eyes, others had crumpled wings, and a few had malformed antenna. The real discovery happened when they brought these butterflies back to a clean lab away from the radiation.
They bred them to see what would happen to their babies. The next generation, the number of physical deformities didn't go down, doubled. The researchers realized the radiation had permanently damaged the butterflyy's [music] blueprints. The eggs in the host plants that they ate were full of fallout, and that damage was being passed down directly from parent to offspring. In 2011, a fisherman in the Gulf of California named Enrique Lucerino Leon caught a pregnant dusky shark. When he cut it open, one of the fetuses inside looked totally wrong. It was pure white, while all its siblings were normal gray.
Oh, and another small detail. Right in the center of its forehead was a single large eye, like a cyclops. Instead of tossing it, he handed it over to marine scientists at National Geographic. They ran X-rays and tests to make sure it wasn't a fake. Of [music] course, it was completely real. The shark had a condition called cyclopia. Normally very early in development, the brain is supposed to divide into two halves and each half forms one eye. In this shark, that split never happened. The brain stayed whole. So there was only one eye socket to form right in the middle.
Animals born this way don't survive long. It can't swim properly or hunt. So they're incredibly rare as is and even rarer to find. The specimen lets scientists get a closer look at exactly what it looks like when that basic step of development goes wrong. Deep under Texas, inside the cave systems of the Edwards aquifer, there's a fish called the toothless blind cat. It lives hundreds of feet underground in complete darkness. It's developed into what it is today over the course of millions of years. It has no eyes at all. Not blind eyes, I mean no eyes. Skin just grows right over the spots where the eyes would normally develop. There's no point in building eyes down there, so the body just [music] stopped doing it. The fish also has zero pigment in its skin, which makes it completely see-through. You can look at one and see its organs, its blood vessels, pretty much everything. I mean, it kind of looks like a raw chicken cutlet. It's not exactly pretty, but it's cool. Scientists find it especially interesting because it shows something counterintuitive. I mean, being completely blind sounds like a pretty major flaw, but in a pitch black cave, having eyes is just a [music] waste of energy. The body eventually stops spending resources on something useless, so the fish is better off for it. You'll also find other pale blind creatures down there, like the Texas blind salamander. And there are other similar eyeless catfish found in Mexico.
Yeah, technically this is not a mutation. It's an evolutionary thing, but it's still pretty strange. In late 2015, a hunter near Preston, Idaho, shot a mountain lion. When he got close to look at it, he found something growing out of the left side of the animal's forehead. hard white mass with a fully formed set of [music] teeth inside it and whiskers growing out the outside. He turned it over to biologists at the Idaho Department of Fish and [music] Game and when they studied the skull, they came up with two explanations and they weren't really able to rule either one out completely. The first was a terteratoma, a type of tumor made of cells [music] that can grow into almost anything, hair, bone, teeth. They sometimes show up in completely wrong places on the body. So that [music] seems to fit pretty well. But the second theory was that the lion had started out as a conjoined twin. The twin stops developing early in pregnancy and gets absorbed back into the surviving animal.
Sometimes there are remnants of the twin left behind. In this [music] case, a jaw. Either way, the lion had been walking around in the wild for years with this extra set of teeth on its forehead, [music] but it seemed healthy until the hunter got to it. Belgian blue cattle look like pro bodybuilders. Their shoulders and hind quarters are enormous, packed with crazy muscle. They look almost nothing like regular cows.
That's not from a special feed or anything farmers are doing. It comes down to one missing protein. In a normal animal, the body makes something called myostatin. It [music] job is to tell the muscles when to stop growing. Think of it as a shut off switch. When the body has enough muscle, myostatin kicks in.
It's just like that's enough. But Belgian blues have a mutation where the gene that makes my statin is either missing or broken. So the switch never flips and the muscles just keep building and multiplying with [music] nothing to stop them which is where the term double musling comes from. They end up with far more muscle fibers than normal.
Geneticists study these animals because the same basic system exists in humans.
If researchers can figure out how to work around myostatin safely, it could open up treatments for people with muscle deficiencies. In 1966, a gorilla was captured in a forest in Equatorial Guinea that looked completely different from any other gorilla anyone had seen.
It had pure white fur, pale skin, and light blue eyes. The gorilla was named Snowflake, and he's still the only known albino gorilla ever documented. [music] Albino animals like Snowflake are born without normal amounts of melanin. Of [music] course, genetic testing later showed Snowflake's albinism came from a mutation a genie inherited from both parents. Because of this lack of pigment though, Snowflake was unusually sensitive to sunlight and prone to health [music] issues. Unfortunately, this made him more vulnerable to skin cancer, which eventually caused his death in 2003. Snowflake spent most of his life at the Barcelona Zoo, where he became a huge attraction. Albino gorillas are so rare that scientists said this case was one in a million.
After most woolly mammoths disappeared from the mainland, a tiny group survived on Wrangler Island in the Arctic [music] for thousands of years. When scientists looked at their DNA, they found a lot of problems. These last mammoths had tons of harmful mutations building up over generations because the population was so small and isolated. Some of the mutations affected their fur, [music] making it kind of satinike instead of the thick wool we usually picture. Being so cut off, the mammoth couldn't get rid of these genetic problems. and over time and added up, making [music] them weaker, less capable of dealing with sicknesses and changes in the weather.
Scientists think this pileup of bad mutations probably helped push the last Wrangler Island [music] mammoths to extinction about 4,000 years ago. Just recently in Brazil, paleontologists came across a strange fossil jawbone in a riverbed. At first, they thought it was just a deformed bone that had been pressed weirdly by rock. But when they found eight more just like it, that's when they realized they'd found [music] a whole new species. They named it Tena Amcola. And the fossils date back about 275 million years, long before dinosaurs ruled the [music] planet. Its jaw was nothing like what you'd expect. Instead of teeth pointing up or down like normal animals, the main teeth pointed out to the sides. Even the part of the jaw that would face the tongue was [music] twisted upward and covered in rows of tiny grinding teeth called dentacles.
The lead scientist who studied it, Jason Partardo, said the jaw has this weird twist that drove them crazy trying to figure out. They spent years wondering if it was a [music] deformation until they realized every jaw had the same twist. Scientists think it used its jaw more like a grinder than a slicer. Maybe chomping on plants or small bits of food in the water.
>> [music] >> They haven't found anything beyond the jaws yet, so things like what its body looked like are still a bit of a mystery. In 2011, a fisherman in the Gulf of California caught a pregnant dusky shark. When the shark was cut open, several embryos were found inside.
Most of them looked normal, but one of them clearly didn't. The embryo, which was about 22 in long, had a single eye sitting right in the center of its head.
When photos of it started getting shared around online, people thought it had to be a hoax. I mean, just look at this thing. It looks like a muppet. But marine biologists who looked at the specimen said the photos were real.
Condition is called cyclopia, which happens when the front part of the brain doesn't split [music] into two halves the way it normally does during early development. And because of that, the face never forms two eye sockets. The embryo ends up with one central eye instead. Researchers also noticed something interesting about the eye itself. It had actually developed optical tissue. So, it had formed the way a regular eye would. Even so, sharks with this condition almost never survive. Cyclopia usually comes with severe brain problems, as you can probably imagine, and so it probably wouldn't have lived long if it had [music] actually been born. In May 2025, a team called Rattlesnake Solutions was called to a backyard in Scottsdale, Arizona to pick up what they thought would be a pretty normal western diamondbacked rattlesnake. [music] Instead, they got one that looked quite different. Instead of the standard crisscross diamond pattern these snakes are named for, this one was covered in round curvy [music] spots that looked more like a leopard's coat. When the team shared the photos of the snake on social media, they were just as amazed as everyone who saw the pics. In their [music] words, "In the many thousands of diamond backs we've seen over the years, this is a first." That's wild when you think about I mean how many rattlesnakes uh they encounter every year. You didn't think it was a hybrid with another species either. The prevailing theory is that it's just a pattern mutation, a fluke genetic change that gave the snake the unusual spots. But according to the group's owner, Brian Hughes, this kind of thing is insanely [music] rare. He said that over the past 25 years, only three snakes with a [music] similar pattern mutation have ever been seen. This one, another near the same area in 2016, and the first about 20 years ago.
>> In 2011, a group of fishermen caught a dusky shark in the Gulf of California.
When they opened the pregnant shark, they found a fetus with one perfectly centered eye. A marine biologist examined the specimen and confirmed it was a genuine case of cyclopia. The mutation happens early in embryionic development and usually leads to fatal defects, but this shark fetus [music] was otherwise completely normal. Scans showed its organs and skeletal structure were healthy. The only abnormality was its single fully developed eye.
Scientists preserved the shark for study, but to this day they can't explain why this case was so biologically clean compared to [music] most other occurrences. In 2018, pig farmers in China began reporting litters with bizarre facial deformities. Some piglets had snouts that curved upwards like a trunk. Others had eyes misplaced on their heads or unusually shaped ears.
Veterary teams investigated dozens of cases. The piglets didn't show signs of chemical exposure or infection, and genetic testing didn't find a consistent mutation either. The deformities appeared randomly in unrelated herds, then faded away months later. Many piglets were otherwise healthy, which made the phenomenon even stranger. While the leading theories point to spontaneous genetic errors triggered by environmental stress, no one has been able to prove it. To this day, it's one of China's most unexplained farm animal anomalies. Two-headed snakes have fascinated and unsettled people for decades. But what makes some of these cases truly mysterious isn't just their appearance. It's how they survive. In 2019, a two-headed copperhead snake was found in Virginia. Instead of dying after a few days, like most do, it lived under observation for months. Both heads were fully functional and shared one body, constantly competing over food and movement. This condition called bicephille is rare but well documented.
What scientists can't fully explain is how some of these snakes develop coordination between the two heads. A few have survived over a decade in captivity. The neurological adaptation required for two brains to share one body and function well is still not understood. In 2015, marine biologist David Gruber made a discovery in the Sullivan Islands that left researchers speechless. While diving at night, his team encountered [music] a glowing hawkill sea turtle emitting bright green and red light. This was the first biofllororescent reptile ever documented. Unlike bioluminescent creatures that create their own light, this turtle absorbed surrounding light and remitted it in neon colors.
Scientists were able to record it and study it, but they still don't fully understand how or why a sea turtle would evolve this ability. It doesn't match typical defense mechanisms or camouflage patterns. This discovery was published in National Geographic and stunned [music] the scientific community. It proved that even large, wellstudied species can still hold incredible secrets.
>> Sometimes a bird watcher will spot a half and half bird. Say a northern cardinal for example. The entire right side of the body is bright red and the entire left is brown. It looks like two different birds fused together straight down the middle. A bilateral genadorph which means half its body is genetically male and the other half is genetically female. [music] Starts with the very first cell division after the egg is fertilized. Normally when that cell splits in two, both new cells get identical genetic information.
But sometimes mistake happens and the chromosomes get divided unevenly.
[music] So, one cell ends up with male chromosomes. The other ends up with female ones. From that point on, each cell builds its [music] half of the bird using its own instructions, so to speak.
Male cells build the right side. The female cells build the left side. That split goes all the way through the body, including the internal organs. The bird can have male bits on one side and an ovary on the other. Next up, we have Stumpy, the four-legged duck, which sounds like a cartoon character, but this is actually a real case. In 2007, a duckling hatched on a farm in Hampshire, England with four legs. The owners called him Stumpy. He had his own normal working legs up front and a second pair growing right behind them. They were smaller and they don't actually function, but they were there. This is called polyia, which just means extra limbs. It happens when the embryo basically gets garbled instructions about where to grow limbs while it's still developing. Most animals born this way don't make it. The extra limbs are just a problem. They dragged, they got caught. Uh, but Stumpy was different.
His extra legs were small enough and positioned just right that they didn't really stop him from walking or swimming. So, he grew up normally alongside the other ducks. One of the extra legs eventually got snagged on a fence and had to be removed by a vet, but otherwise he was completely [music] healthy. There's a rare hereditary skin condition called epidermma dysplasia, verifis. You might have seen photos of people with this. It's usually just referred to as the treeman disease. To get it, a person has to inherit a broken copy of a specific gene from both parents. If only one parent passes it down, doesn't show up. So, this is very rare, thankfully. The genes involved are called ever one and ever two. Their job is to help the immune system recognize and fight off a virus called human paploma virus, HPV. Most people carry some version of HPV and their bodies deal with it without any issues. But whenever one and ever two are both broken, immune [music] system doesn't recognize the virus at all. So the virus moves into the skin cells and forces them to produce massive amounts of keratin, the same tough protein [music] that makes up our fingernails. So nothing so nothing to stop it. Keratin builds up into these thick, rough, almost bark-like growths, mostly on the hands and feet. Doctors have to surgically remove them. Two-headed animals are called polyphilic and they show up most often reptiles, snakes especially, and sometimes turtles. It's not caused by pollution or anything in the environment though, the process is almost identical to what creates identical twins and humans. So when a fertilized egg starts developing, it's supposed to split fully into two separate embryos. That split starts but doesn't finish. The cells just keep growing anyway, [music] connected. The result is one body with two heads. Each head has its own brain, its own eyes, but they share everything below the neck. So, the same heart, the same lungs, the same digestive system. In the wild, they almost never survive because it's basically two different snakes fused together, and they often just can't cooperate with each other. Makes escaping from predators a bit of a problem if they both want to slither in a different direction. In captivity, scientists have kept them alive for years, though. But one well doumented behavior at feeding time, they've had to put physical barriers between the two heads because snakes have been known to fight over the same piece of food.
Neither one understands that the food's [music] going to end up in the exact same stomach regardless. In 2019, a fisherman on Lake Champlain pulled in a trout that looked totally normal at first, but when she went to take the hook out, she noticed the fish had a second mouth right below the first one.
Photos started spreading online. People assumed that maybe it was edited.
Biologists looked at it and they confirmed the fish was real, though.
Sometimes a fish survives an old hook injury where the jaw tears open and then heals in an unusual shape which can look like a second mouth. But a case where a sort of second mouth forms during development, that's pretty rare. What surprised scientists though was the fact that the fish was a full-grown adult. A second opening in the throat usually causes real problems with breathing through the gills or it just makes it nearly impossible for them to swallow food. This one had gotten around both those problems though, which isn't something anyone was expecting.
Superbugs are bacteria that have developed resistance [music] to the antibiotics we rely on to treat infections. This is becoming a bit of a concern because it means that infections which used to be easy to treat with simple antibiotics [music] could become deadly again. And these superbugs can spread quickly, especially in places like hospitals where people are already weakened by other health issues. Bacteria learn to fight off the treatments we use to kill them. [music] So the usual treatments don't work anymore. In some cases, even the strongest antibiotics available have no effect. If things were to continue like this, we might be looking at a world where simple cuts or infections could become life-threatening again. And things that used to be manageable like pneumonia or urinary tract infections could be lethal. We've already seen some superbugs in action. The most famous example is probably MRSA which resists [music] common antibiotics and can cause everything from minor skin infections to more serious ones. There are others out there like C deficil and multi-drugresistant tuberculosis. And without new antibiotics or treatments, the future could look a lot like it did before antibiotics were discovered. A lot of people could die from infections that we just don't [music] think twice about cuz they're so easy to treat.
Apparently, our DNA has a lot of what's called the junk, which are stretches of genetic material that don't seem to have any specific purpose. But scientists are starting to worry that some of this so-called the junk DNA might suddenly turn on in ways we don't understand. If these dormant genes were to activate, they could cause unexpected mutations in our cells, leading to diseases or even new forms of cancer. The problem is they don't know exactly what these dormant genes do. I don't know, though. I mean, why be all doom and gloom about it?
Maybe these dormant genes are more like [music] the Xgene in X-Men and will start having people with laser eyes and the power to control the weather. They should look into that. If these genes were to wake up though, they could potentially start producing harmful proteins or cause other genetic problems that result in serious health issues.
Some scientists again think that certain forms of cancer might be [music] linked to junk DNA. Gene editing technology, especially crisper, has been a pretty huge leap in science. [music] They can now make some incredibly precise changes to DNA, which opens up all sorts of possibilities from curing genetic diseases to creating crops that are resistant to pests. But there's a looming threat behind it, the risk of unintended mutations. Even though Crisper is incredibly accurate, it's not perfect. Sometimes it can cut or alter DNA in unexpected ways, creating problems that no one saw coming. Changes like this could potentially cause new diseases or make existing ones even [music] worse. One big concern is that these unintended mutations could be passed on to future generations, making the problem even worse. Imagine editing a gene to prevent a disease, but instead you accidentally create a new health issue that's even worse than the one you were trying to avoid in the first place.
And of course, forget mistakes. Even sometimes people just cause harm intentionally. Another fear is that crisper could be used to [music] create bioweapons and god knows what else.
There's definitely a lot of good that can come from gene editing, but still a lot we don't know about what can happen long term. Xenobiology is the study of life that isn't quite like the life we know on Earth. It's about creating new artificial life forms, organisms that don't naturally occur in nature, but are designed by humans. So, with advances in synthetic biology, scientists have already created [music] bacteria and even yeast that have been altered. As you can probably guess, though, the big concern here is that these artificial life forms could mutate in unpredictable ways, creating new diseases or causing harm to the environment. One of the biggest worries is that these new life forms could escape the lab and spread [music] into the wild, where they might compete with or disrupt natural ecosystems. Let's say we had some genetically altered lab bacteria that could eat plastic, but instead of stopping once it's eaten enough, it just mutates to start breaking down other materials that are essential to life. Or imagine we had a synthetic organism that can survive in extreme environments like the deep ocean and suddenly becomes a global threat. There's a very real potential for unpredictable consequences. [music] And as we get better at creating life in a lab, the risks of these organisms mutating into Frankenstein-like creations also becomes more of a possibility. Oine spongififor and seephalopathy or to put it in fancier terms, mad cow disease, is a deadly disease known as a pryion disease. A disorder of the brain that affects [music] cattle and can in rare cases be transmitted to humans through infected beef. This disease is caused by what's called a misfolded protein.
[music] a protein that has folded incorrectly, resulting in a toxic shape.
Once it takes hold, it leads to brain degeneration. So, what if a pryion disease like mad cow were to mutate, [music] making it more easily spread and deadly?
The thing about prime diseases is that they're incredibly difficult to treat.
There are no antibiotics or antiviral treatments that work against them, and they often take years to develop symptoms. And as cattle farming practices change or new methods of processing [music] meat are introduced, these types of diseases could evolve and spread in ways that we're just [music] not prepared for. And because pryion diseases are so contagious and devastating once they take hold, scientists are keeping a close watch on the possibility that new mutated forms [music] could grow and pose a serious risk to global health. A two-headed brown trout was found in a creek in southern Idaho. And it wasn't the only deformed fish in the area. Scientists found more trout with facial deformities, twisted fins, and defective eggs. And it all pointed to one thing, selenium pollution. Selenium is a metal that shows up naturally in the environment, but when it builds up from things like mining or coal burning, it becomes toxic. In this case, the pollution was traced back to operations run by JR Simplot, a massive aggra business company that processes food and chemicals. They funded a study to look into the deformities. And while the report claimed that the selenium levels were safe, others strongly disagreed.
Joseph Scorpa, a wildlife biologist with the US Fish and Wildlife Service, said the study was biased and quote highly questionable. He pointed out that it completely skipped over the effects on birds and reptiles and seriously downplayed the deformity rates in fish.
Meanwhile, in Tennessee, politicians started pushing bills to deregulate selenium altogether. See, the coal industry has a stake in this, too.
What's happening in one Idaho Creek is just one part of a much bigger picture.
There's this fish called the Clear Lake Hitch that only lives in Clear Lake, California. And some of them have developed a mutation known as pug headedness, [music] which you can probably form a pretty clear image of in your head. They end up with steep, almost boxy foreheads, bulging eyes, and an underdeveloped upper jaw. Basically, the top half of the mouth doesn't grow right. So, it ends up shorter than the bottom, making the whole face look warped. Scientists think this is thanks to pollution, mainly from pesticides and mercury that have built up in the lake over time. The hitch used to be everywhere in this area. They were a big part of the diet for indigenous tribes like the Pomo. And back in the day, you could see massive runs every spring.
These days, even in a good year, only a few thousand show up to spawn. Some years, [music] barely any. Out in the middle of the Mojave Desert, there's this tiny deep pool called Devil's Hole.
It looks like just a weird blue hole in the ground surrounded by dry rocks, but it's actually a deep water-filled crack in the earth, kind of like a natural well. And inside this tiny pool lives one of the rarest fish in the world, the devil's whole pup fish. These fish are tiny, smaller than your pinky finger, [music] and they've been living here for thousands of years. The water is warm, nearly 90°, and has very little oxygen.
The fish need that exact setup to survive. It's a very specific environment, but they've adapted perfectly until recently. Right now, there are only about 75 of these fish left, and scientists are worried. Their genes are a mess. Scientists have found what's called genetic load. Basically, these fish are drowning in bad DNA, and there's [music] no way for natural selection to clean it out. This leads to what's called an [music] extinction vortex, where the genetic problems make it even harder to survive. Back in the 70s, conservationists built backup tanks [music] to protect the pup fish in case the wild ones died out. But at one of these tanks, some pup fish from a nearby but different species snuck in. Their babies mixed with the DNA and grew way faster and healthier, even sprouting extra fins. The hybrids exploded in number, which showed biologist Andy Martin that introducing new genes was probably the solution here. Martin thinks the devil's whole pup fish could be saved if they bring in a few of these cousins from a spring just a few miles away. But some conservationists [music] hate this idea. To them, it's not really saving this specific species of fish if [music] you're changing their DNA. Nano silver. That sounds like an anime attack, but this is a real particle causing mutations in fish. Silver and nano particles, tiny particles smaller than viruses, are used in over 200 consumer products because they kill bacteria on contact. Scientists are now worried these little particles might [music] be messing with the environment and wildlife. When silver nano particles wash down drains, they end up in rivers, lakes. Darren Ferguson, a researcher at the University of Utah, tested these particles on zebra fish embryos in the lab and found some pretty scary mutations. Some of them became quote extremely distorted, almost making a number nine or a comma instead of a linear fish. He said the particles cause deformities in eyes, tails, and most disturbingly their hearts. And here's something pretty scary. Zebra fish actually have organs kind of similar to ours, so this could hint at risks for people, [music] too. Scientists still don't know exactly what this means for us or the planet long term, but the Environmental [music] Protection Agency said the same special properties that make nanocale materials useful are also properties that may cause some nanocale materials to pose potential risks. In California's Kersonen Reservoir, a big environmental problem popped up because of selenium pollution. Selenium is a naturally occurring element, but when it builds up too much, it becomes toxic. In Casterson, the water got contaminated with high selenium levels, mainly from irrigation runoff. The fish there, especially embryos, started coming out with serious deformities. Some had messed up eyes or were just missing them completely. There were deformities in their fins, the brain. Scientists call this cluster of problems Kestrin [music] syndrome. And it's not limited to fish because the birds eating them also suffered. Birds have been found with deformed beaks, legs, and wings. In Ona Lake, New York, walley fish started appearing with tumors. This comes from exposure to chlorinated wastewater effluent. That's water discharged from treatment plants containing [music] chlorine byproducts. So, these chemicals don't break down easily and can build up in the lake. These tumors are obviously a sign that pollution in the lakes has [music] carcinogenic effects, meaning it can cause cancer. Walleye are especially important, too, cuz they're popular for fishing. So this is worrying not only scientists but fishermen and the communities who depend on the lake. Back in the 70s a coal fired power plant in North Carolina started dumping waste water full of selenium into Bellow's Lake. Over time it completely wrecked the fish population. By the early 2000s the number of fish species in the lake dropped from 24 down to just six. Most of the fish couldn't reproduce anymore.
One study found that 19 of the original 20 species couldn't produce any surviving offspring. Only smaller fish that ate plankton, like mosquito fish, managed to stick around. They weren't affected as badly by the selenium buildup. Eventually, the plant stopped dumping the waste into the lake in 1986.
Levels of selenium in the water dropped way down and they even restocked the lake with sport fish like bass and bluegill. But even 10 years later, the fish were still having trouble reproducing. That's because selenium sinks to the lake bed and slowly leaks back into the food chain, especially if storms stir up the sediment. To make things even worse, some illegally introduced Alabama bass in 2011. They started out competing the native bass, especially largemouth. Now, state officials are trying to get rid of them by removing catch limits, but the damage is already being done. In the Great Lakes, especially Lake Ontario and Lake Michigan, scientists have seen lake trout hatching with strange deformities.
They found fish with weird faces, swollen yolk sacks, which are the little sacks attached [music] to fish embryos that hold the nutrients they need to grow, and they have bloated areas around the heart, symptoms known as blue sack disease. It's caused by exposure to dioxins and toxic [music] chemicals that build up in the water over years from things like industrial waste and pesticides. These toxins settle in the sediment but work their way up the food chain. Fish at the top, like lake trout, get hit hardest because they eat smaller contaminated fish. The damage mostly shows up in the embryos, so it's affecting reproduction more than anything else. Many of the baby fish just [music] don't survive. These deformities were first spotted decades ago and are still showing up in areas where dioxin levels are high. Even though regulations have cut down on the amount of dioxins going into the lakes, the old contamination is [music] still there. Now, we've talked about all the bad stuff going on with fish, but what about some interesting adaptations?
Well, Atlantic Tomcot in the Hudson River developed a mutation that lets them survive in waters full of toxins.
For decades, the river was basically a chemical dumping ground. Chemicals that usually kill or will seriously harm fish. But scientists have noticed that Tomcott have developed a genetic mutation that changed how they process pollutants. Normally, these chemicals get into a fish's cells and start causing damage. But this mutation messes with the pathway [music] the pollutants usually use. Instead, the fish store the toxins in their fat, basically locking them away where they can't cause a whole lot of harm. This trait didn't show up everywhere. It's specific to Tomcod that live in polluted water. The downside though is that these fish are now heavily specialized to survive in dirty, polluted water. If the environment changes again, even if it's for the better, they might not adapt fast enough. And they're still concerned about predators eating them and taking in those same toxins up the [music] food chain, including people who eat the fish. Killfish are tiny, colorful fish found along the east coast, often in places no other fish would want to be, like New Jerseyy's New York Bay or Virginia's Elizabeth River, where there's a lot of toxic waste. These areas are loaded with dioxins and heavy metals. But somehow killish are doing pretty well all things considered. Turns out they've evolved an insane resistance, up to 8,000 times more than [music] normal. Researchers collected hundreds of killfish from different polluted sites and sequenced their genomes. And what they found was that each population had developed similar mutations in the same genes that basically turned off the normal response to these toxins. This kind of resistance is only possible because killfish have super high genetic diversity. For other species that don't have that kind of variation, adapting like this isn't really an option. Again though, there's still food for birds and bigger fish, so there's still a lot of worry as to how all that stored up pollution could affect the rest of the food chain. Most of us know that when you open your eyes underwater, things get [music] blurry.
That's because the water and the fluids inside our eyes are pretty similar in density, which messes with how light passes into the eye. The result, blurry vision. But there's a group of people called the Mochan who can actually see clearly underwater, even at depths of up to 22 m or about 75 ft. The Mochen live mostly on boats or stilt houses, only heading to land to trade for food and supplies. They don't use modern diving gear like masks or fishing poles.
Instead, they spend a lot of time underwater gathering resources from the ocean floor like sea cucumbers and clams. And over the course of generations, the Mochin's eyes have actually developed the ability to change shape when they're underwater. They refract light better, making it easier to see things clearly underwater. Tests have shown that the underwater vision of Mochen people is twice as sharp as Europeans. Sleep is a basic human need, and everyone constantly harps on 8 hours. You got to get 8 hours of sleep or you're just crumbled to pieces throughout the course of the day. And 8 hours is probably ideal for the majority of the population, but some people really don't need 8 hours. There's a rare genetic mutation called DEC2 that allows certain people to function on just 6 hours or even less of [music] sleep every night. And not just survive on it, it's actually ideal for them. The DEC2 mutation affects the way their bodies process sleep, [music] making them more efficient at getting the rest they need in a shorter amount of [music] time. It's uh quality over quantity. For most people, getting only 6 hours of sleep a night for a prolonged time [music] can lead to some serious health issues like high blood pressure or heart disease. But people with this mutation don't have those problems. If you think you're one of these people, though, you are probably not. This mutation is incredibly rare. It's found in less than 1% [music] of people who even claim to have this ability. I usually only get 6 hours of sleep a night or less. And [music] let me tell you, I don't feel great most of the time. Hyperthinesia is a rare condition where people can remember nearly every detail of their lives with perfect clarity. Able to recall what they did on a random day years before. Keep in mind, I'm not talking about like your wedding or the day your child was born. Uh if you remember those things, great. Uh, but you probably should be able to remember those things. I'm talking about really detailed things like even what they ate for breakfast on a random day 5 years ago. It's like they have files in their brains full of footage of every single day of their life. Now, this sounds like a pretty amazing ability, but it can actually be a double-edged sword. For some, remembering every single moment of their lives, especially the more painful ones, can be [music] a bit overwhelming.
Scientists are still trying to figure out how the brain is able to store and access all this information. But this condition is so rare that there are only a few confirmed cases. [music] Imagine not feeling any pain no matter how serious the injury. Again, this sounds like a real life superpower, and I suppose it kind of is in a way, but like with most superpowers, there's a downside. The condition is called congenital insensitivity to pain or CIP.
And you don't really need to think about it much to realize that this can be a pretty dangerous condition. Pain sucks, but it is there for a reason. It alerts us to things that are harmful to us. So, not being able to feel pain at all.
Well, it makes it much harder to know when you're injured or sick. People with CIP could break a bone or get an infection without ever feeling it. So [music] things can be left untreated and then conditions can worsen. Even something as simple as stepping on a sharp object might go unnoticed and it can lead to infections. [music] CIP is caused by a mutation that affects nerve cells responsible for sending pain signals to the brain. Researchers are also studying to see if they can develop new treatments for chronic pain through this condition. Most people worry about losing bone density as they get older, which can lead to conditions like osteoporosis and brittle bones. But for a small group of people, the opposite of true. Their bones just continue getting denser as they [music] age. This mutation is found in the Africconer population and people of Dutch descent living in South Africa. It's linked to a mutation in a gene called SOS, which controls bone growth. Normally, this gene [music] keeps bone growth in check.
But in those with the mutation, their bones keep getting stronger throughout their lives instead of weaker. If someone inherits two copies of the mutated gene though, it causes a rare condition called sclerosiosis which leads to excessive bone [music] growth.
This can result in gigantism, facial distortions, hearing loss. But if a person again only inherits one copy of the mutated gene, they have unusually dense and strong [music] bones. Again, this mutation is extremely rare, but researchers are studying it because it could of course help in developing treatments for bone related conditions.
Some people are naturally stronger than others, but a rare genetic mutation known as myostatin related muscle hypertrophy takes strength to a whole new level. Myostatin is a protein that normally limits muscle growth in humans.
But there are some people who are born with a mutation that reduces the effect of myostatin, [music] which means their muscles keep growing without the usual restrictions. As a result, they develop extraordinarily strong and dense muscles, often far beyond what would be expected of a normal person. Apparently, Eddie Hall has this, but some people aren't really sure. I wouldn't be surprised. He's incredibly strong. Anyway, people with this condition don't really need to hit the gym for hours a day to build muscle.
They're born with the genetic ability to just grow massive, [music] powerful muscles naturally. Hard to see any problems with this one, but there are some downsides. People with this condition may develop joint issues because of the sheer size and power of [music] their muscles. Imagine sharing your body with someone else and having to coordinate every action you make.
That is the reality for people with polyphily, [music] a condition where a person has two heads or I guess you could say two people have one body. This happens when conjoined twins don't fully separate during development and sometimes the heads are joined at the neck [music] or share the same body.
It's incredibly rare with only one in 50,000 to even 200,000 pregnancies resulting in polyphilic twins. Usually, they'll have control over half of their limbs. But it can get complicated. Each twin can control their own side, but both, of course, need to work together to move. Some people with polyphille can walk, run, and even [clears throat] drive. But it's not always straightforward. Occasionally, one of the heads might not have much control over the body, or not [music] any at all. That's known as parasitic head and sadly attempts to remove it through surgery usually don't work. Most polyphilic people fortunately don't survive into [music] adulthood. So most of us see the typical seven colors in a rainbow. Red, orange, yellow, green, blue, indigo, [music] and violet. If you count more colors though, you may be someone with a rare condition called tetrachromacy. People with tetrachromacy have four types of color detecting cells in their eyes instead of the usual three. This extra type of cone cell means they can see way more shades than the average person. They can spot subtle differences in color that most of us [music] just don't notice. One famous example of someone with tetrachromacy is Australian artist Ketta Antico. As you can imagine, her paintings are pretty vibrant, just full of color. And I would just [music] love to see her work through her eyes. Photographic memory, also called idetic [music] memory, is something most of us have heard of before. And people are pretty liberal about throwing this term around, too.
But it's a lot more rare than people realize. [music] It's the ability to remember images, even entire pages of text only after a brief glance. Similar to hyperthimeia, people with photographic memory can recall every little detail as if they're looking at a mental snapshot of a moment in time.
Again, some people claim to have photographic memory, but true photographic memory [music] is incredibly rare, and experts aren't totally sure how it works. What scientists [music] do know is that people with photographic memory seem to have special neural processes in their brains that just allow them to encode and retrieve visual information much more efficiently than others. Some brain regions responsible for memory and visual perception are [music] more active than people with disability. But no one fully understands the exact [music] mechanics yet. Aging.
Unfortunately, it happens to all of us.
All we can do is drink water, rub our faces with lotion, sleep better, and hope for the [music] best. But for a few lucky folks, the typical signs of aging, like wrinkles and gray hair, don't show up as quickly. And I'm sure a bunch of you are going, "Well, duh. Obviously that's true." But I mean, not nearly as quickly. This condition known as delayed aging means that some people simply just age way slower than the rest of us. They appear youthful even as they get older, often staying healthy and vibrant long into their later years. Their bodies also resist age related diseases like Alzheimer's or heart disease, [music] and they seem to have more energy and stamina than other people their age.
Scientists are still figuring out how this happens. [music] But it's believed that certain genetic mutations might make their bodies more resilient to the usual wear and tear that comes with getting older. [music] Unlike the other conditions on this list with benefits and downsides, there's really no downside I can think of about this one other than being [music] IDed more at bars. I mean, anyway, who cares really?
Studying delayed aging is [music] important because it could give us a chance to slow down the aging process and live longer, healthier lives for the general population. If we can figure out how some people manage to stay so youthful and strong, scientists might be able to create treatments that could help everyone stay in better shape as they get older without all the usual aches, pains, [music] and health problems. Starting off this list today, we are talking about double-headed snakes. Ever been startled by nature's own glitch? Double-headed snakes are one of the most jaw-dropping examples of polyphille, a condition where an embryo fails to fully split during development.
These snakes emerge with two heads, each with its own set of instincts that can conflict with one another. Imagine one head wanting to attack while the other hesitates. This internal tugofwar often leaves the creature struggling [music] to feed or move properly. And while this phenomenon is most famously seen in snakes, it's also been spotted in turtles, lizards, [music] and even birds, it's a wild reminder of how delicate and unpredictable nature can be. Next, we are talking about the cyclopic [music] fish. What could go wrong with a fish's blueprint? Cyclopic fish with a single central eye instead of the usual pair are a startling example of developmental disruption.
These mutations typically result from severe genetic errors or exposure to toxins during early growth stages, leaving the fish with a disorienting, almost cartoonish appearance. The lone eye is rarely enough for proper vision, making survival nearly impossible.
Scientists study these rare cases to uncover the intricate [music] signaling pathways involved in eye formation, turning what might seem like a gruesome anomaly into a key puzzle piece in understanding developmental biology.
Next, we are talking about the amphibian limbs. Ever seen an amphibian that doesn't quite fit the mold? Frogs and salamanders sometimes hatch with extra [music] missing or oddly deformed limbs due to genetic glitches or environmental disturbances like pollution and parasitic infections. [music] These mutations don't just make for a bizarre appearance. They can severely impair an animal's ability to escape predators or forage for food. While these deformities might sound like something from a horror story, they also offer researchers invaluable insights into how environmental factors can disrupt the delicate process of limb development in [music] nature. Next, we are talking about the ocular growths. What if a creature's eyes went [music] rogue? In rare cases, amphibians are born with extra or misaligned eyes due to aberrant ocular growth. These malformed structures can throw off the creature's entire visual system, resulting in significant impairments that make it difficult to navigate [music] or to hunt. Although such mutations are extremely uncommon, they provide [music] scientists with a unique window into the complexities of eye development, revealing just how finely tuned and vulnerable these processes really are.
Next, we are talking about the insect appendages. [music] Ever noticed an insect that looks like it came with bonus parts? Sometimes genetic errors or environmental stressors [music] cause insects to sprout extra wings, legs, or antenni, turning an ordinary bug into a walking, flying oddity. These extra appendages aren't superpowers.
They tend to hinder the insect's ability to move, feed, and survive in the wild.
Yet, this bizarre twist of natures offers entomologists [music] a fascinating glimpse into how even minor disruptions in the [music] genetic blueprint can lead to dramatic and unexpected changes in form and in function. Next, we are talking about turtle shells. [music] What if nature's armor wasn't built to last? Turtles and tortoises sometimes hatch with malformed shells, gaping, asymmetrical, or oddly contoured due to developmental mutations. Their shell is their primary defense against predators, [music] and any flaw can leave them dangerously exposed to environmental hazards. often linked to temperature fluctuations during embryionic development. These shell deformities are a stark reminder of how even slight changes in early conditions can have lifealtering effects on the animals survival.
>> EV stands for this. It's sometimes referred to as the treeman disease. EV is an ultra rare genetic condition that causes uncontrollable growth of wartlike lesions all over the skin. The weird thing is these lesions are caused by certain types of HPV, the same virus that causes, you know, common warts, but almost everyone's immune system fights off HPV before it gets serious. In EV patients, their immune system doesn't work properly against these HPV [music] types. Scientists found mutations in two specific genes that seem to break the immune system's ability to control the virus, but they're not sure exactly why.
[music] Because of this, the HPV spreads unchecked, causing large, scaly lesions that can look kind of like tree bark, which is where the nickname treeman disease comes from. One of the most well-known cases was a man from Indonesia who lived with the condition for over 20 years before passing away.
The lesions covered his hands, feet, and his [music] face. Doctors don't have a cure, so treatment focuses on just removing the growths [music] and managing infections. Diproopus is a super rare condition where a person is born [music] with parts of their face duplicated. This can mean anything from having two noses or two mouths to nearly just two full faces on one head. It's so rare that there have only been about 36 confirmed cases of this. Scientists think this happens because of a problem with a protein called Sonic Hedgehog, not making that up, which controls how the face develops before birth. When this protein is too active, it can cause the face to split or duplicate. But exactly why this happens in some pregnancies and not in others, it's still a mystery. Most people born with this don't survive long because the condition usually comes with other serious problems, especially in the brain and the internal organs. Sometimes the duplicated parts aren't fully formed. Other times they're more complete. Doctors and researchers have studied cases over the years, but there's still no clear explanation for why it happens. It's not inherited.
Instead, it seems to be a random error during early development. It's one of the rarest and most baffling birth anomalies corted. Progeria is a crazy rare genetic condition where you age way faster than normal. It's caused by a mutation in a gene called LMNA, which makes a protein important for keeping cells stable. When that protein is messed up, cells get damaged faster, [music] and the body shows signs of aging early. You know, you'll have hair loss, wrinkled skin, heart problems.
Kids with progeria usually look like tiny old people, even though they're actually really young. It's super rare.
Only about 400 cases have been confirmed around the world. Those born with it usually only live into their early teens, and most die from heart disease.
There's no cure yet, but some treatments can help with symptoms and maybe slow down the aging a little. Even though scientists know the gene involved, the full picture of how this works at a molecular level is still a mystery, which makes it one of the most puzzling human mutations we know of. Next up is something called mermaid syndrome, which sounds kind of nice, but it isn't.
Scientifically, it's known as sirenia.
This is a rare condition where you're born with your legs fused together, looking kind of like a mermaid's tail.
It's extremely uncommon and sadly it's usually fatal because it comes with serious problems [music] inside your body. You'll have missing or malformed kidneys and just lots of issues in this general [music] area. As you can imagine, doctors think it happens because the blood flow to the lower part of the fetus gets messed up early in pregnancy, but they don't fully understand why. Some studies say it might be caused by things like maternal diabetes or exposure to certain toxins, but they're not entirely sure. Unlike conditions caused by a single gene mutation, mermaid syndrome seems to come from a mix of things, but this is so rare that only a few hundred cases [music] have ever been documented.
Polyphille means having two heads on one body. It's an extremely rare type of conjoined twins where [music] instead of two bodies, they're just one with two separate brains. Each case is different.
Sometimes both heads have control over parts of the body. Sometimes one is more dominant. How these twins share organs and nerve [music] control varies a lot, so each case is unique, which makes it tricky for doctors. Scientists know polyphille happens when an embryo [music] starts to split into twins, but then doesn't fully separate. What's not clear is why it stops halfway, [music] leaving two heads on one body. It's not inherited and seems to be a random developmental glitch early in pregnancy.
survival is rare because contrary to what cartoon logic would have you believe, having two brains actually puts a huge strain on the [music] body. It's it's not a good thing. There have been documented cases in both humans and animals, but very few survive for long.
When they do, it raises all kinds of medical and [music] ethical questions about treatment and quality of life.
Even with modern medicine, scientists still don't fully understand how these twins brains [music] manage to coordinate the body or why the condition happens in the first place. Fibroplasia acific progressiva or FOP if you want to get all fancy. It's one of the rarest and weirdest genetic disorders. People with FOP have a mutation in a gene called ACVR1 that makes their body turn muscles, ligaments, and other soft tissue into bone. It's like their body starts building a second [music] skeleton slowly just traps them in place. Imagine your muscles turning to stone over time. Terrifying, but that's kind of what happens here. The mutation causes the body's normal repair process to go totally wrong. Instead of healing injuries like normal, the body just reacts by creating bone where it shouldn't. Scientists still don't fully understand why this happens, but they know it's tied to the way cells communicate during bone growth. FOP is very rare. Only about 800 cases have ever [music] been documented. People with it usually start showing symptoms in early childhood and it just gets worse over time. there's no cure and surgeries to remove the extra bone often just make things worse because as you can imagine the body will just create [music] more bone in response.
It's a rare condition where someone is born missing some of the middle fingers or toes which makes their hand or foot look like a split kind of clawike.
That's why it's sometimes called lobster claw hand. The exact causes are complicated. It happens because of changes in certain genes that control how fingers and toes develop in the womb. These gene changes [music] can be different from person to person, which is why eodactyl can show up in a lot of ways. Some people might be missing just one finger. Others have more severe splits. The condition doesn't follow a simple pattern. That means it doesn't always get passed down in families [music] in a clear way. Sometimes it just happens randomly during development. The gene mutations affect the process where the hand or foot forms from tissue called the limb butt, causing the central digits not to develop or just [music] to fuse together. This one isn't life-threatening, though. A lot of people do live normal lives and find ways to adapt to it. Although back in the day, [music] they would usually be put in the circus. But because the exact gene changes can vary a lot, scientists don't fully understand why the condition happens or why it looks so different [music] in different people.
Hypertriosis is a super rare condition where people grow way more hair than usual, thick hair, even on places that don't normally have it. It can show up at birth or develop later. But the form people are born with happens because of genetic mutations [music] that mess with how their hair grows. One of the earliest recorded cases was a guy named Petrus Gonzalus from the 1500s who had so much hair that people called him the werewolf man. The hair can cover the face, the arms, the back, [music] sometimes just the whole body, making it look more like fur than hair. Even though it's not dangerous, can obviously definitely make life pretty hard socially. I can only imagine how bad it must have been in the 1500s. I mean, some people would have been trying to drive a steak through his heart or burn him alive. Scientists still aren't totally sure why the mutation makes the hair grow so much or why it picks certain body parts to cover. There are only a few hundred confirmed cases around the world, so it's super rare.
Maren syndrome is a genetic condition that affects connective tissues, all the stuff that holds your body together like skin, bones, and organs. People with Marfin usually have really long limbs and fingers plus super flexible joints.
Sometimes their hearts are affected as well because the blood vessels. This happens because of a mutation in a gene called FBN1, which controls a protein called fibrillin one. This protein gives strength and stretchiness to tissues. So when fibrillain one doesn't work right, the body parts it supports just get weaker and stretch out more than they should. Some people with this condition might barely notice it. Others need serious medical [music] care to protect their heart and lungs. With the right treatment and monitoring, most people with this live full active lives.
Scientists have learned a lot about this one, but they're still studying how to prevent the serious issues that it can cause. Imagine never feeling pain. I bet some people would wish for this, but but for people with congenital insensitivity to pain or CIP, it's actually a big problem. This rare genetic condition means their nerves don't send pain signals to the brain properly. So, they don't notice when they're hurt. Because of this, they often injure themselves without realizing it. Might burn [music] their skin, get infections. There have been cases of people with this condition breaking their bones and not knowing.
CIP [music] happens because of mutations in certain genes that interfere with how nerve cells send pain messages to the brain. Scientists study it closely because understanding this condition, I mean, it's not only going to help people with CIP, but they could also develop new pain treatments for everyone else.
The tricky part is since pain is the body's way of protecting itself, not feeling it [music] means these people have to be extra careful all the time.
>> Next, we are talking about two-tailed lizards. Ever been intrigued by a lizard with an extra tail? Lizards are known for their impressive tail regeneration skills, but sometimes this process goes ary, resulting in a bifurcated or split tail. [music] While a two-tailed lizard might seem like something out of a fantasy novel, the extra tail usually disrupts the creature's balance and coordination, making everyday survival a bit of a tougher challenge. Interestingly, this mutation isn't always permanent. It can be the result of incomplete regeneration following an injury, offering a quirky insight into nature's remarkable yet [music] imperfect repair mechanisms.
From turtle shells, we are now talking about crab shells. What happens when a crab's armor becomes a bit of a burden?
Exposure to pollutants or random genetic anomalies can [music] cause crabs to develop grotesqually misshapen exoskeletons. These abnormal growths not only distort the crab's appearance, but also impede its movement and feeding abilities, turning [music] it into an easy target for predators. Despite the grim reality for the affected crabs, studying these mutations helps marine biologists understand the environmental pressures [music] that can disrupt crustaceian development and highlights the vulnerability of marine ecosystems to external stressors.
Next, we are talking about bird wings.
Ever wondered how a bird survives with uneven wings? Some birds hatch with asymmetrical wing development, where one wing is noticeably different in size or shape from the other. This imbalance can be catastrophic, severely limiting their ability to fly, evade predators, or compete for food, often indicative of deeper developmental issues. Such wing deformities serve as a harsh reminder that nature's precise engineering isn't infallible. For the birds effective, even a small deviation in wing symmetry can mean the difference between survival and a life grounded by physical limitations. And finally, to end off this list, we are talking about blob [music] plants. What if a plant's growth turned into a bizarre work of art?
Fascination is a mutation where a plant's growing tip becomes elongated, [music] flattened, or swollen, resulting in oddly bloblike structures that defy the usual natural [music] symmetry. Though this mutation might produce a look that's almost otherworldly or a little bit grotesque, it provides scientists with unique insights into the genetic and environmental factors that influence plant development. [music] Triggered by everything from genetic errors to infections or even physical damage, fascination challenges our expectations of natural beauty and reveals the unpredictable side of nature's creative process. group of people can naturally stay underwater far longer than almost anyone else. The bio of Southeast Asia live their lives on the ocean and rely heavily on deep diving. When researchers studied them, they found a hereditary mutation in a gene that enlarges their spleens by up to 50%. Larger spleens store more oxygenated red blood cells, and when they dive, that oxygen is released into their bloodstream, letting them stay underwater for minutes at a time. This mutation appears almost only in this group of people, not in neighboring populations, not in similar coastal groups. A real modern example of human adaptation shaped by isolation and lifestyle.
During an extreme drought in the Amazon, people started seeing dolphins turning unusually bright pink. Pink river dolphins normally have a soft rosy color, but in Lake Tephe during the 2023 heatwave, researchers documented dolphins with intense full body pink coloration. The mutation appears linked to heat stress and blood vessel expansion near their skin. Younger dolphins showed the effect the strongest, suggesting a developmental trigger. Some dolphins eventually faded back to normal colors. Others stayed bright. It is one of the clearest examples of environmental pressure creating rapid visible changes in an isolated species.
Most people struggle to breathe at high altitude. Tibetans thrive there because of a mutation almost no one else has. A gene called EPA1 inherited from ancient human ancestors.
It prevents blood from thickening at low oxygen levels. This lets Tibetans live at altitudes that would leave most people dizzy or sick. The mutation is incredibly common in the region but extremely rare outside of it. It is one of the strongest known cases of inherited human adaptation preserved because of the harsh and isolated environment of the Tibetan plateau. In a remote region of Kazakhstan, generations of families began noticing the same disturbing pattern. Birth defects, growth abnormalities, and unusually high rates of rare cancers. There was a test site that was the Soviet Union's main nuclear testing zone for decades.
Between 1949 and 1989, more than 400 nuclear tests took place there. Some were underground, but many were atmospheric, sending radioactive material drifting straight into surrounding villages. Decades later, researchers discovered something alarming. People in these remote villages showed genetic mutations passed down through multiple generations. Some mutations affected bone development.
Others altered immune function. Some increased susceptibility to diseases not normally seen in the region. And these people here never evacuated. Many did not even know that they were living in fallout. So the mutations accumulated slowly and spread within families.
There's nothing supernatural about it.
It is simply the longl lasting biological impact of radiation exposure combined with extreme geographic isolation. Inside central American mangroves lives a fish that does not need a partner to reproduce. The mangrove killifish can self-fertilize, producing offspring that are nearly perfect genetic clones. It evolved this ability because the swamp pools it lives in frequently become isolated or temporarily uninhabitable. When a pool dries or becomes cut off, a single killifish can repopulate the area once conditions improve. Very few vertebrates on Earth can do this. It is one of the strangest real reproductive mutations ever documented.
Researchers deep in the Bornean rainforest found indigenous families with bright blue eyes and no European ancestry at all. Genetic testing showed the diac groups do not have the same blue-ey mutation found in Europeans.
They developed an entirely separate mutation that created the same trait through a completely different genetic path. This rare case of convergent evolution stayed preserved because the communities were extremely isolated for generations. Wolves living inside the Chernobyl exclusion zone are bigger and genetically different from wolves outside the region. Scientists found mutations related to immune response and DNA repair which help them tolerate constant lowdosese radiation. Wolf populations inside the zone are also estimated to be dramatically higher than outside it.
The mutations were not engineered. They were developed naturally as the wolves adapted to an environment with no humans and persistent radiation exposure. A small coastal region in Japan saw an outbreak of severe developmental disorders caused by industrial pollution. From the 1930s to the 1960s, [music] mercury contaminated wastewater was dumped into Minimata Bay. When pregnant women ate contaminated fish, the mercury disrupted fetal brain development. Babies were born with a syndrome now known as congenital minima disease. This was a developmental mutation, not a genetic one. It changed how the brain formed in Udo, caused entirely by environmental exposure in a geographically isolated [music] community. In one of the most remote mountain regions of Siberia, researchers found sheep with unusually [music] dense skull bones. The isolated snow sheep of the Ptorana Plateau showed mutations affecting [music] bone development. Their skulls and horn bases were noticeably thicker than normal, likely an adaptation to harsh cold and heavy predation pressure. Because the herd was cut off from other populations, the mutation strengthened over time instead of being diluted. In one remote region of South America, an entire population developed a mutation that allows them to survive something that should be deadly. In parts of northern Argentina and the Adakama region, local drinking water naturally contains high levels of arsenic, some of the highest on Earth. But instead of widespread poisoning, researchers discovered something unexpected. People in this isolated area carry a rare mutation in the gene AS3MT, which dramatically increases the body's ability to detoxify arsenic. For most humans, arsenic builds up in the body and causes organ damage. For this population, the toxin is processed and expelled far more efficiently. The mutation is thought to have developed over thousands of years of exposure to the contaminated water supply. What makes it truly strange is how localized it is. Populations just a few hundred miles away do not have this protection.
It is one of the strongest real examples of humans evolving resistance to a natural poison.
Fungal infections are another area where mutations could cause huge problems.
Candida Rus, for example, is a pretty nasty fungus that people tend to get in hospitals when they already have weakened immune systems. [music] What's really creepy about this one is that it's mutated to become resistant to most antifungal treatments. So, it's almost impossible to get rid of. It can cause severe infections, especially in people, again, with weakened immune systems. And because it's so resistant to treatment, it's a nightmare for doctors trying to treat it. But the problems don't stop there. Fungi like Candida RS get better at surviving in hospital environments where they're more likely to come in contact with vulnerable patients. And because they're so hard to treat, they can spread quickly between patients, making outbreaks much harder to contain.
The fear is that if these fungi keep mutating, they'll become [music] even harder to fight, potentially leading to even deadlier infections that can spread across entire hospitals or communities.
As our oceans continue getting warmer, scientists are seeing an increase in the amount and size of toxic algae blooms.
Now, toxic algae blooms or harmful algae blooms happen when certain types of algae grow out of control, producing toxins that can cause all sorts of [music] problems. These toxins can contaminate drinking water, poison marine life, and even cause neurological diseases in humans. Some of these algae produce a toxin called domoic acid, which can poison shellfish, which in turn causes brain damage in humans who go on to eat [music] the contaminated seafood. And the issue is only expected to get worse as the planet keeps getting warmer. The ocean becomes the perfect condition for algae to thrive. And as these algae blooms become more common and more toxic, they're posing a bigger and bigger [music] threat to ecosystems underwater and our human health. In the same vein, pollution and radiation is causing issues with fish. We're starting to show signs of some pretty bizarre mutations. Some fish have been found with extra fins, [music] extra eyes, or other strange mutations that you just rarely see in nature. Only now, [music] it's becoming more common.
Mutations like this can be caused by chemicals and radiation, leaking into the environment from industrial buildings like [music] power plants and factories. What's worrying scientists is that these mutations could potentially spread to [music] other species and mess up entire ecosystems. If these mutated fish were to pass on their altered genes to their offspring, it could result in entire populations of animals with extra eyes or tentacles and tumors. It just be a mess. And as nasty as that would be, it could have ripple effects in the food chain, affecting everything from the fish that humans eat to the animals that depend [music] on these fish for food.
We're already seeing signs of these mutations in fish populations near areas with heavy amounts of pollution. And there's real concern that as these changes spread, we might see bigger shifts [music] in marine life that could be difficult, if not impossible, to undo. Environmental radiation is another huge concern when it comes to mutations.
This can come from nuclear accidents like Chernobyl or Fukushima, radioactive waste, or even just natural sources of radiation in the environment. [music] When plants, animals, or even humans are exposed to this radiation, it can cause pretty gnarly genetic mutations. And these mutations can get passed down through generations. There are cases of what's called the Chernobyl heart, for example, a heart condition in infants whose mothers were exposed to radiation in Chernobyl. And these mutations can spread [music] throughout ecosystems affecting populations of animals and plants. Over time, the genetic changes could accumulate leading to new diseases [music] and deformities. Again, the Chernobyl disaster created this huge area of radioactive contamination, and scientists have found a whole bunch of mutations in animals and plants living there. Some of these mutations are mostly harmless, but others could lead to long-term health problems [music] or even extinction for certain species.
Radiation mutations aren't always spotted immediately either. It can take a while for them to manifest, but they can be incredibly dangerous in the long [music] term. And another concerning mutation that's getting more attention is the rise of chemical induced mutations [music] in plants, especially crops. Pesticides and herbicides, which have been used to protect plants [music] from pests and weeds, are causing some pretty weird and unexpected genetic changes in the plants themselves. Over time, these chemicals can create [music] mutations that make the plants more resistant to the chemicals, leading to what are called super weeds that are harder to control. And once again, some of these mutations might be passed [music] on to future generations of plants, creating entire populations that are resistant to herbicides [music] and pesticides. What if we were to run out of ways to protect crops? [music] We'd have no vegetables, which of course means no popcorn at movie theaters, meaning I'd probably never bother going to the movies again. And that is a terrifying note to end
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