Compared to many other species, all humans have incredibly similar genomes. However, even small changes in our genes or our environment can lead to some very unique traits being developed. Sometimes these differences manifest themselves as a change of hair or eye color, but other times it’s something way cooler and more significant.
Here are some genetic quirks you didn’t realize were normal.
1. Red Hair
Although seemingly everyone has a soulless ginger friend, this hair color occurs only in 4-5% of people. In Northern Europe, redheads are born more often, making some researchers believe that such mutation is a genetic response to the lack of sun, shorter days, and longer nights, but nobody knows for sure. It could very well just be the lack of negative selection that removes unnecessary mutations.
2. Lactose Tolerance
Lactose tolerance is one of the finest examples of human evolution that is now being actively discussed. While milk is considered commonplace among modern humans, other mammals stop drinking it when they reach maturity because they lose the ability to digest it. Ten thousand years ago, Europeans began to domesticate cows. During that period, a mutation has occurred, allowing some people to continue producing the necessary enzymes that make drinking milk safe for us. Well, for most of us.
3. Blue Eyes
Although only about 8% of the world’s population has blue eyes, the mutation that gave rise to this beautiful feature is incredibly old for our species. The first blue-eyed person lived in Spain seven thousand years ago. Prior to that, everyone had brown eyes, but researchers have established why they turned blue. The gene responsible for the amount of brown pigment produced by the iris was turned off, resulting in cool blue eyes.
4. Sneezing at Bright Light
Oddly enough, some people are genetically predisposed to sneeze from looking at the sun, and this is not that uncommon. Between 10% and 35% of people sneeze upon sudden exposure to bright light, and the scientists call this mutation “the light sneeze reflex.”
5. Morning Coffee Is a Must
Many people cannot wake up without a cup of coffee, and they only have their genes to blame for that. Research shows that caffeine has different effects on various genotypes. The reaction to foreign substances and stimulants, like caffeine, is also controlled by genes.
6. Lack of Wisdom Teeth
Wisdom teeth are more of a problem than a necessity. And when they start bothering people, dentists prefer to pull them out rather than treat them. 350,000 years ago, large molars were vital for our ancestors, as they munched on tough plants and raw meat. Due to the dietary changes, our wisdom teeth have gradually stopped growing, and now about 40% of Asians, 45% of Inuit, 10-25% of Americans, and 11% of African Americans never develop them at all.
7. Short Sleep Syndrome
Some people can doze off for ten to twelve hours only to wake up tired and beat up. But a certain mutation makes other people require just a few hours to get a good night’s sleep. People with this gene only need 3-4 hours to feel fresh and rested the next day. Oh, how I envy those lucky few.
8. Alcohol Intolerance
When some people with a certain genetic mutation drink alcohol, their cheeks start to flush a lot due to the dilation of the face’s blood vessels. And although a red face is completely harmless, it can indicate that you may have alcohol intolerance.
9. Fish Smells Nice
Studies have shown that some people never get bothered by the stench of fish but not because they like the smell, but because their brain thinks they’re smelling caramel, roses, or even potatoes. This mutation is extremely rare and so far has only been found in people from Northern Europe.