SCIENCE

Redhead Genetics Linked To Evolution, But Extinction?

Happy Roodharigendag (that's Redhead Day in Dutch). It's a summer festival that takes place the first weekend in September in the Netherlands. This year, nearly 5,000 people gathered to celebrate all things fiery red, especially this unique phenotype.

But what exactly is the genetic story behind red hair? How do redheads get that auburn tone? And does their rumored extinction have any actual scientific backing?

Click the link below and watch the video above to find out. And don't forget to sound off in the comments section below. Come on, talk nerdy to me!

Hi everyone. Cara Santa Maria here. I heard the other day that people with red hair are going extinct. Then I looked it up online, and wouldn't you know, there it was, all over the place: the great demise of the redhead. Luckily, we don't believe everything we see on the Internet. (More on that later...)

How do redheads get that coppery tone? Melanin. It's a pigment found in human skin and hair that gives it color. It's made by special cells appropriately called melanocytes. We all have them, but some people's produce more melanin than others. Like people with albinism: they produce little or none. Biologically speaking, and I say this with love, of course, redheads are mutants. See, melanocytes have a special receptor on them that tells them to produce a certain kind of melanin. It's called the melanocortin-1 receptor, and in redheads, it doesn't work properly.

Fair skin and freckles are hallmarks of redheadedness. But with those unique signs of beauty comes an increased risk of developing skin cancer. And strangely, research has suggested that that women with red hair require higher doses of anesthesia. But a recently published study by a team of Australian scientists suggests no significant effect of hair color on anesthetic requirements or overall patient recovery. Clearly, more research is needed to get to the bottom of this. Because even though red is the rarest hair color on earth, there are still a fair amount of redheads out there.

Although estimates vary, the number is likely less than 1 percent of the world population. But nearly one-tenth of the Irish population has red hair, and in Scotland, it's nearly 13 percent. Nobody knows exactly when the first red haired humans came on the scene, but it may have been a relatively recent arrival--between 20 and 40 thousand years ago. And even older hominins--neanderthals, to be exact--probably had red hair too, although it came from a completely different gene variant. When that happens it's called convergent evolution, like how bats and birds both developed wings, but through completely different evolutionary processes.

As I said earlier, having red hair is usually caused by a mutation. And this mutation is passed down recessively. That means that both of your parents have to carry the recessive gene for you to have a chance of having red hair. Two redheads make a redhead, but so can two brunettes, as long as they're both carrying that mutated gene. And only about 4 percent of the overall population does.

This brings us back to whether or not redheads may be going extinct. Well, if you think back really hard to your high school biology class---oh who am I kidding? The answer is no! The more we travel around and mix our genes in this giant melting pot, the more diluted that redhead gene variant will become. But recessive traits don't get bred out of a population. Genetics doesn't work that way. Recessive genes are tricky--they hide behind their dominant counterparts. So don't you worry redheads, you are not the last of a dying breed.

Redheads, sound off! Reach out on Twitter, Facebook, or leave a comment right here on the Huffington Post. Come on, talk nerdy to me!

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