Bizarre but True: Common Traits You Didn’t Know are in Your Genes!

Achoo Syndrome

We usually think of genetics as something related to eye color, blood groups, or diseases like diabetes. But what if we told you that your odd sneeze in sunlight or your dislike for coriander could all be in your genes? From the funny to the frustrating, many quirky human traits are hardcoded into your DNA. Let’s explore some of these fascinating and often bizarre genetic surprises.

1. ACHOO Syndrome — Sneezing at the Sun?

Imagine walking out of a dark movie theater into sunlight—and suddenly sneezing. You're not alone. This condition, hilariously named the ACHOO syndrome (Autosomal Dominant Compelling Helio-Ophthalmic Outburst), causes some people to sneeze when exposed to bright light.

This isn’t due to an allergy—it’s a reflex likely linked to crossed signals in your brain between the optic nerve (vision) and the trigeminal nerve (involved in sneezing). Studies suggest it runs in families and follows a dominant genetic pattern, meaning if one parent sneezes at the sun, you probably do too!

Gene involved: Possible link to ZEB2 gene region

2. Lactose Intolerance — Not Everyone Loves Dairy

Many people feel bloated, gassy, or sick after drinking milk or eating ice cream. This could be lactose intolerance, the inability to digest lactose, the sugar in milk.

Humans are born with the enzyme lactase, but in many adults worldwide, the production of this enzyme drops with age. However, certain populations (especially Europeans) have a gene variant that keeps lactase active throughout life—a condition called lactase persistence.

Gene involved: LCT gene (regulated by a variant in the MCM6 gene, like SNP rs4988235)

3. Cilantro Tastes Like Soap?

Some people love coriander (cilantro), while others say it tastes like soap. This isn’t a matter of picky eating—it’s genetic!

The OR6A2 gene makes a smell receptor that detects aldehydes, chemicals also found in soap. If your version of the gene is sensitive, you’ll pick up the soapy taste in cilantro leaves.

Gene involved: OR6A2

4. Male Pattern Baldness — It's Not Just Your Mom

Think baldness skips a generation or only comes from your mom's side? Not really.

Male pattern baldness is actually a mix of many genes working together—that's what we call a polygenic trait. It’s not just about one gene. One key player is the AR (androgen receptor) gene on the X chromosome, which you inherit from your mom. This gene influences how your hair follicles respond to hormones like DHT, a big factor in hair thinning and baldness.

But it’s not just about the X chromosome—there are other genes on different chromosomes that also come into play. So, your chances of losing hair can come from both your parents, not just one side of the family. Plus, things like stress, what you eat, and getting older can speed up how fast those genes show up in real life.

Genes involved: AR, plus many others identified in genome-wide studies

5. Alcohol Flush Reaction — The “Asian Glow”

Some people turn red and feel warm or sick after drinking alcohol. This is known as alcohol flush reaction, and it’s most common in East Asian populations.

This reaction happens because of a defective ALDH2 enzyme, which normally breaks down a toxic alcohol by-product. Without it, the toxic compound builds up quickly, causing redness, nausea, and a racing heart.

Gene involved: ALDH2 (notably the rs671 variant)

6. Morton’s Toe — The “Long Second Toe” Surprise

Look down at your feet—does your second toe appear longer than your big toe? That’s Morton’s toe, and it may be in your genes.

Although more research is needed to pinpoint exact genes, this trait often runs in families. It’s not a deformity; just a variation in bone length and toe placement.

Gene involved: Unknown, likely polygenic

7. Contagious Yawning — Why You Yawn When Others Do

Yawning is natural. But why do you yawn when someone else does—even over a video call? This is called contagious yawning, and research links it to empathy and brain connectivity.

Some studies suggest genetics play a role in whether or not you “catch” yawns. People with autism spectrum traits or lower empathy scores are less likely to be affected. While no single gene has been nailed down so far, brain structure and function appear to be involved.

Gene(s) involved: Still under study; linked to neurological function

8. Color Blindness — Not Always a Boy’s Club

Most people with red-green color blindness are male, but it can affect females too (though rarely). That’s because the genes for color vision lie on the X chromosome.

Males have one X chromosome, so one faulty gene can cause color blindness. Females have two Xs, so both would need to carry the faulty gene for them to show the condition—making it less common in females.

Genes involved: OPN1LW, OPN1MW (on X chromosome)

9. Migraines That Run in the Family

Not all headaches are genetic, but familial migraines, especially hemiplegic migraines, often are. These severe headaches can come with numbness, vision problems, and even temporary paralysis.

Researchers have found mutations in SCN1A, a gene that controls ion channels in nerve cells, in some forms of inherited migraines.

Gene involved: SCN1A, CACNA1A, ATP1A2

10. Joint Hypermobility — More Than Flexibility

Can you bend your thumb back to your wrist? Or do your joints move more than others’? That may be joint hypermobility, which sometimes signals a connective tissue condition like Ehlers—Danlos Syndrome (hEDS).

In most flexible people, it’s just a harmless quirk. But in others, especially with symptoms like pain or dislocation, genes involved in collagen structure may be affected.

Genes involved: Still under investigation; possible links to TNXB and others

You may have thought these little quirks were just part of your personality or luck of the draw—but they are often encoded in your DNA. Whether you sneeze at the sun, taste soap in your salad, or glow after wine, your genes are whispering (or shouting!) their secrets.

So the next time you notice something unusual about your body, habits, or preferences, don’t brush it off. Science might have a beautiful, genetic explanation.

References

1. https://www.crigenetics.com/blog/achoo-photic-sneezing-reflex.htm

2. https://www.helix.com/blog/genetics-dna-achoo-syndrome-allergies

3. https://www.23andme.com/topics/traits/photic-sneeze-reflex/

4. https://www.xcode.life/genes-and-allergy/how-does-genetics-influence-your-risk-for-photic-sneeze

5. https://en.wikipedia.org/wiki/Photic_sneeze_reflex

6. https://pubmed.ncbi.nlm.nih.gov/28132945/

7. https://www.helix.com/blog/dietary-intolerance-genetics

8. https://humanpeople.co/blogs/longevity-insights/genetic-insights-into-lactose-intolerance

9. https://www.fitnessgenes.com/blog/lactose-tolerance

10. https://arxiv.org/abs/1209.2096

11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1470658/

12. https://www.everydayhealth.com/foot-health/mortons-toe.aspx

13. https://pmc.ncbi.nlm.nih.gov/articles/PMC6875787/

14. https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-023-09721-7

15. https://en.wikipedia.org/wiki/Yawn

16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3968284/

17. https://pubmed.ncbi.nlm.nih.gov/9620288/

18. https://www.23andme.com/topics/traits/male-pattern-baldness/

19. https://www.verywellhealth.com/can-women-be-color-blind-5092910

20. https://www.wired.com/story/monkeys-with-superpower-eyes-could-help-cure-color-blindness/

21. https://arxiv.org/abs/1403.6801

22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9319525/   

23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4609397/

24. https://pubmed.ncbi.nlm.nih.gov/25338840/

Blog Credits: This blog has been reviewed and validated by Dr. Siva Lakshmana Teja Alapati, MD FIICA, Associate professor - Cardiac Anesthesia.

Image Credits: The image of this blog has been generated using Gemini AI for better resonation.