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.

Stop! You’ve been using these 11 objects the wrong way

Image: Diana Polekhina

We use countless objects daily without questioning their design, yet many have hidden features or were meant for entirely different purposes. From kitchen tools to bananas, here are 11 everyday items you might be using all wrong—or that at least have surprising secrets built in.

Image: Anastasia Nikitina

Yes, toothpaste was always intended to clean and polish teeth, but its mild abrasives make it effective for cleaning jewelry, removing stains from clothing, and even defogging mirrors.

Interestingly, the first toothpaste-like substance dates back to ancient Egypt, where a blend of pumice and vinegar was used for oral care. Modern toothpaste, which includes ingredients like baking soda—another household staple—explains why it’s so effective on surfaces beyond just teeth.

Image: Markus Winkler

That hole in your pasta spoon isn’t just for draining water; it can also help measure a perfect portion of dry spaghetti!

A single serving of spaghetti is about the amount that fits through the hole. This design prevents cooking too much or too little, though not all pasta spoons have holes large enough for accurate measuring.

Image: engin akyurt

The latch inside gas pump nozzles was originally designed to shut off fuel flow automatically when the tank is full, not to hold the pump open.

Modern pumps use this mechanism as a safety feature, preventing spills and overflows. In some places, using the latch to hold the nozzle open is even illegal due to fire risks.

Image: Karsten Winegeart

Those metal loops on the back of grocery cart seats aren’t just for show—they’re designed to hold plastic bags with fragile items.

Hanging lighter bags here prevents them from being crushed by heavier groceries in the cart, yet few shoppers take advantage of this simple design. So, next time you go shopping, give it a try—it could be a real lifesaver.

Image: Bam Mccarthy

The hole in a soda can tab isn’t just part of the opening mechanism—it can double as a straw holder. Once you pop the can open, turning the tab around aligns the hole perfectly for a straw. This prevents the straw from floating or shifting while drinking.

While this wasn’t the original intent behind the design, it’s a clever and surprisingly convenient way to make use of an otherwise inconsequential design quirk.

Image: Annie Spratt

If you're like me, this has likely been a brain teaser since childhood: What is the blue side of a two-tone eraser for? Popular wisdom says it's for ink removal, but have you ever tried erasing ink with that side? It just completely obliterates the paper.

Well, it turns out the blue side of a two-tone eraser was actually designed for use on heavier paper, not for removing ink.

Image: Matúš Kameniar

The small bumps on the ‘F’ and ‘J’ keys exist to help typists find their hand placement without looking.

These tactile guides help your fingers find their way back to the home row, enabling faster and more efficient typing. Even if you're not a professional typist, you can rely on this feature to improve both speed and accuracy while writing.

Image: Monika Guzikowska

Ever watched a monkey peel a banana? You might be in for a surprise, because it turns out the easiest way to peel a banana is from the bottom, not the stem.

Monkeys naturally pinch the bottom of the banana and pull, avoiding the struggle of breaking the tough stem. This method also reduces the risk of squishing the fruit inside.

Image: Brett Jordan

The small hole at the end of a measuring tape is designed to hook onto nails or screws for one-person measurements. This feature provides a more stable grip when measuring long distances without needing an extra set of hands.

Also, the serrated edge on some tapes doubles as a tool for marking surfaces. So, next time you don't have a buddy around to help, don’t worry—your measuring tape has you covered!

Image: Andrea Davis

Many people use the drawer under their oven for storage, but it was originally designed as a warming drawer.

This compartment keeps cooked food warm while the rest of the meal finishes, though in some modern models, it may simply be intended for extra storage. Checking your oven’s manual might reveal its true purpose.

Image: Mockup Free

Ever heard someone say you can judge a good wine by the depth of the indentation at the bottom of the bottle? Well, that’s a myth, though it may suggest a better-designed bottle.

The indent at the bottom of a wine bottle, called a punt, helps distribute pressure and maintain structural integrity. Originally designed to support the bottle against carbonation in sparkling wines, it’s now mostly tradition but still improves durability.