In your genes

This is in your DNA: 12 weird traits passed down from long ago

Image: Cade Proulx

You may have never met your great-great-grandparents, but their biological legacy lives on in you in ways you might not expect. From tiny quirks in your body to odd preferences and physical features, ancestral survival and lifestyle choices have shaped what you carry today. Here are 12 surprising traits that science has linked to deep genetic inheritance.

Image: Katya Ross

A thumb that bends backward at the top joint is known as a hitchhiker’s thumb. It results from a single gene variant.

This trait is controlled by a variation in the gene responsible for joint flexibility. Some people have it in both thumbs, while others only in one. It's a harmless variation that may have been more common in populations requiring greater dexterity.

Image: Max Leveridge

Some babies are born with blue or gray eyes that change color over time. The way this shift unfolds is written in your DNA.

After birth, melanin production in the iris increases over time. Genetic variants in the OCA2 and HERC2 genes regulate melanin levels. These subtle changes can take months or even years to settle into a final eye color.

Image: Alex Guillaume

The ability to roll your tongue into a tube shape is often thought to be purely genetic, and that’s partially true. While you can learn to do it with a lot of practice, studies show it’s also influenced by genes.

Some populations have a higher percentage of tongue rollers, and the trait may have originally been a byproduct of muscle control needed for speech or food manipulation in early humans.

Image: Tim Trad

Acrophobia, or intense fear of heights, has a genetic link tied to survival instincts from your prehistoric ancestors.

People with heightened depth perception or balance issues may inherit a stronger fight-or-flight response to elevation. This reaction likely helped early humans avoid dangerous cliffs or falling from trees.

Image: KaLisa Veer

Strange as it sounds, redheads often experience pain differently. Some studies suggest they have a higher threshold for certain types of pain, while others indicate increased sensitivity to specific stimuli like cold or heat.

This is linked to ancient adaptations in the MC1R gene, which influences melanin production and also affects pain modulation through opioid receptors in the brain. Variants of this gene were more common in populations from colder regions, such as prehistoric Europe.

Image: Chermiti Mohamed

Freckles are genetic, but they bloom with sun exposure due to the way ancestral DNA interacts with UV light.

In fact, the same MC1R gene involved in red hair also influences how melanin clusters into freckles. This is because freckling was advantageous for fair-skinned populations needing some UV protection without full pigmentation.

Image: Anita Jankovic

The ability to digest milk into adulthood is a relatively recent mutation in human history. Populations with pastoralist ancestors—such as Northern Europeans and some East Africans—evolved lactase persistence, the continued production of the enzyme lactase that enables them to digest milk throughout adulthood.

Most of the world remains lactose intolerant, but those with this mutation can thank their ancestors for a genetic advantage linked to dairy-based survival.

Image: Thomas Park

Weirdly enough, some people sneeze when exposed to sunlight or even just bright lights. This phenomenon, known as the "photic sneeze reflex," affects 18–35% of people and is linked to genetics.

While this inherited quirk is harmless, it likely results from crossed nerve signals between the optic and trigeminal nerves, the latter of which controls facial sensations and reflexes like sneezing.

Image: Claudia Love

Also called Morton’s toe, this feature was once thought to improve balance or running efficiency. The trait is hereditary and common in certain populations.

Greek statues often depict this toe shape, suggesting it was either idealized or prevalent in ancient Mediterranean groups. Biomechanical studies show mixed results, but some suggest that a longer second toe can affect posture and gait.

Image: Mika Ruusunen

People with ancestry from colder regions often have inherited a better tolerance to cold. Adaptations such as higher basal metabolic rates, subcutaneous fat distribution, and heat-conserving blood vessel responses are linked to genetic clusters in populations like the Inuit or Sámi.

Genes like UCP1, which influence fat burning and thermogenesis, are more active in these populations.

Image: Marco Bianchetti

Some people have a vestigial muscle in the forearm that others lack entirely. Called the palmaris longus, it once helped tree-climbing primates enhance their arm strength.

Today, about 14% of people are born without it in one or both arms. It has little to no effect on grip strength, making it a living fossil of human evolution. Interestingly, when present, it’s often harvested for surgical grafts because its absence doesn’t impair function.

Image: Bethany Beck

Clockwise or counterclockwise hair whorls are influenced by genetics, and some studies link their direction to the same genes that affect handedness. However, identical twins can sometimes have opposite whorl patterns, suggesting a mix of genetics and early fetal environment.

This trait has no known survival function but may serve as a visible marker of underlying developmental processes during early embryonic growth.

10 weird historical events that no one has been able to explain (yet)

Image: Walters Art Museum, Public domain, via Wikimedia Commons

Who doesn't like a good mystery? And if the mystery isn’t a work of fiction but the result of a true story, even better! The great unsolved enigmas of history are absolutely fascinating. Some have been solved over time, but there are still many old secrets for which neither scientists nor historians have found an explanation—yet. Time-travel with us as we uncover 10 of the biggest historical mysteries that will probably never be cracked!

Image: Tanner, Henry S., Public domain, via Wikimedia Commons

Bermeja Island is mentioned in navigation texts written by European travelers and appears in cartography from the 16th to 19th centuries. Old maps place it off the north coast of the Yucatán Peninsula; however, multiple searches over the years have yielded no concrete evidence of its existence.

So, what happened to Isla Bermeja? Was it a cartographic error? Did it sink due to a tidal wave? Because of its geopolitical significance, some have even suggested that it was blown up by the CIA! A 2009 study by the Autonomous University of Mexico concluded that Isla Bermeja does not exist today, nor were any traces found at its supposed coordinates. Yet, it will forever remain a mystery that will surely keep many entertained.

Image: Credit: Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO)., Public domain, via Wikimedia Commons

In 1977, Ohio State University’s Big Ear radio telescope, used in the search for extraterrestrial intelligence, detected a signal now known as the Wow! signal. While reviewing the data, astronomer Jerry R. Ehman noticed a sequence represented as "6EQUJ5." Baffled by the anomaly, he circled it and wrote "Wow!" in the margins.

The signal lasted 72 seconds and, unfortunately, has never been repeated. To this day, no one can fully explain the phenomenon, although some suggest it may have come from a man-made source. Still, the Wow! signal remains one of the strongest candidates for potential extraterrestrial contact ever detected.

Image: Edward S. Curtis, Public domain, via Wikimedia Commons

How is it possible for an entire village to vanish without a trace? Believe it or not, this is said to have happened nearly a century ago. According to lore, a small Inuit village in Canada was well known among fur trappers who visited regularly to trade. But in 1930, something very strange supposedly occurred.

A hunter named Joe Labelle claimed he visited the village one day and couldn’t find a single person. Reports said there were guns and food left behind, and even claims that the graves in the cemetery were empty. A thorough investigation, however, found no conclusive evidence of what happened to the villagers. Some witnesses from nearby towns even reported seeing a huge green light. Theories ranged from mass migration to extraterrestrial abductions. The Royal Canadian Mounted Police has since dismissed the case as an urban legend. Some still believe the story to be true.

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We know thousands of shipwreck stories, but this one is quite unique. The MV Joyita, designed to be nearly unsinkable, was found adrift in the South Pacific, practically unharmed, but the crew had disappeared completely.

In October 1955, the American merchant vessel left the port of Apia in Samoa with 16 crew members and 9 passengers bound for the Tokelau Islands. After days without news, a rescue mission was launched. Five weeks later, the Joyita was spotted more than 600 miles west of its intended route. The vessel was partially submerged, and there was no sign of the passengers or crew. Four tons of cargo and all three life rafts were missing. They were never seen again.

Image: Gary Todd from Xinzheng, China, CC0, via Wikimedia Commons

Do you know where one of the best-preserved mummies was found? Hint: not in Egypt. Xin Zhui, the Marquise of Dai during the Western Han Dynasty in China, was discovered in her tomb at Mawangdui 2,000 years after her death, along with hundreds of valuable documents and artifacts.

What makes this mummy so extraordinary is how well-preserved her body is. Her organs and veins remain intact, and she still has hair and even eyelashes. Scientists analyzed the fluid present in the coffin and discovered it was acidic and contained salt and magnesium. They believe this mysterious liquid may have been responsible for preserving Xin Zhui so well. What they don’t know is whether it was intentionally poured into the coffin or came from the body itself.

Image: Yoichi Okamoto, Public domain, via Wikimedia Commons

The United States has its fair share of presidents who died while in office, but none of our 45 presidents have ever disappeared without a trace. Did you know that this actually happened in The Land Down Under?

Harold Edward Holt was the Prime Minister of Australia from 1966 until his presumed death in 1967. He loved the ocean and spearfishing. During a weekend trip with friends, Holt visited the remote Cheviot Beach to take a swim. Rough sea conditions that day caused him to be swept away by the waves, and he never reappeared. Despite an intensive search, his body was never found, which has given rise to numerous conspiracy theories. Ironically, Australians built the Harold Holt Memorial Swimming Centre in Melbourne in his honor.

Image: FBI, Public domain, via Wikimedia Commons

Many famous criminals have managed to remain unidentified for decades, but the D.B. Cooper case is something else entirely. In 1971, Cooper boarded a flight from Portland to Seattle. Shortly after takeoff, he showed a flight attendant a device he claimed was a bomb and demanded four parachutes and $200,000 in cash.

The crew landed to meet Cooper’s demands in exchange for the passengers and then took off again. As the plane flew over southwestern Washington, Cooper jumped into the cold, rainy night carrying his haul. His whereabouts and true identity were never discovered, although it is likely he didn’t survive the jump. In 1980, some of the ransom money was found near the Columbia River. Although the FBI officially closed the case in 2016, amateur sleuths continue to try to crack it.

Image: Pieter Brueghel the Elder, Public domain, via Wikimedia Commons

Can you imagine an epidemic where the main symptom is uncontrollable dancing? Sounds like science fiction, doesn’t it? Yet this really happened during the Middle Ages. In 1518, a dancing plague struck Strasbourg, Alsace, in what is now France. This strange condition affected up to 400 people, making them dance frantically for weeks. It is said that some even died of heart attacks, exhaustion, or strokes.

Doctors and authorities tried all kinds of measures to stop the spread. They even banned music for a while! To this day, scientists are not certain what caused this bizarre condition: it may have been food poisoning from toxins in the ergot fungus, or perhaps a case of stress-induced mass hysteria.

Image: Public domain, via Wikimedia Commons

The Voynich manuscript is a codex written roughly 500 years ago in an unknown language and writing system by an anonymous author. Known as Voynichese, the manuscript was named after Wilfrid Voynich, a Polish bibliophile and antiquarian who purchased it in 1912.

Radiocarbon testing has shown that it dates to the early 15th century. Many cryptographers and codebreakers have attempted to decipher its roughly 240 pages without success. The manuscript contains diagrams and illustrations of unknown plants and astrological symbols. Some believe it may be a made-up language, a secret code, a work of fiction, or even a hoax. If you think you can solve this mystery, the Voynich manuscript is available for viewing at Yale University’s Beinecke Rare Book and Manuscript Library.

Image: Bernhard

Similar to the Voynich manuscript, the Phaistos Disc is a fired clay disc believed to have been created during the Bronze Age. It was discovered by an Italian archaeologist in the basement of a palace in Crete, Greece, in 1908.

What makes this disc fascinating is that it contains a mysterious message. Stamped into the clay is a set of signs, forming a text that many scientists have tried to decipher—without success. It is considered an early attempt at printing, a technological innovation that would not become widespread for several centuries. While enthusiasts still hope the enigma can be solved, this is unlikely unless other documents are discovered to provide context.