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Hair Color

I am a natural redhead since birth and recently read in the newspaper that redheads will be extinct by the year 2100. Is this a good possibility and if so could I preserve my eggs for the red hair gene?

-A curious adult from Kentucky

October 6, 2005

Redheads are definitely on the decline. Unless there is some unknown advantage to having red hair, they will eventually become very rare. But they will not disappear altogether.

Of course the gene for red hair will still be there -- it will just be hidden. So freezing your eggs won't necessarily help humanity. It may keep red hair in your family for a while, but it won't really help preserve red hair overall.

So why is red hair declining? And if the red hair gene is still out there, why will there be so few redheads?

This is very much a question of numbers. There are few redheads to begin with. Estimates say that only 4% of the human population carries the red hair gene. As if this wasn't bad enough, red hair is also recessive.

Recessive means you have to have two copies of a certain version of a gene to show a trait. (Remember, we have two copies of most of our genes -- one from mom and one from dad.) So this means that of the 4% who have the red hair gene, an even smaller percentage actually have red hair.

The gene that causes red hair is called MC1R (melanocortin 1 receptor). No matter what your hair color, everyone has this gene.

The red hair version of this gene, though, has slight changes that cause the red hair color. If only one of your MC1R copies has these changes, you won't have red hair, but you will be a carrier of the red hair gene.

One of the reasons red hair has stuck around for as long as it has is that people didn't used to travel very much. There were pockets of red hair, like in some areas of Scotland. In these small areas, the chance that two carriers would meet and have redheaded children was very high.

But humans are more mobile now, and populations mix more than they ever have before. Carriers of the red hair gene move away from these pockets in Europe, and non-carriers move in. This means the red hair gene is getting diluted into the general population more quickly than in the past.

There will still be carriers (people with only one copy of the red hair gene). But since they won't all live in the same place, the chances of two of them meeting and producing a redheaded child will be very low.

This is why, even though the gene may not die out, the number of redheads will continue to decline. However, for as long as the gene is still circulating, the chance of a red haired child being born is not zero. So you can expect one turning up every now and then, just less often. (Click here for a calculation of how many redheads there may be in the world in the future.)

One thing that can affect whether a gene stays around or not is if there is some advantage or disadvantage in having it. So if it were helpful to have the red hair gene around, it would increase in frequency. If there were a disadvantage, it might decline.

Most versions of the red hair gene also cause very fair skin. You may have noticed that redheads often have the lightest skin color around. Scientists think that it's this fair skin color that gave people advantages and disadvantages in the past.

 The red hair gene originally arose in Northern Europe, because having fair skin was an advantage. How? Because it lets more sunlight through than dark skin. When sunlight enters your skin, it stimulates the production of vitamin D, and that protects you from getting diseases like rickets.

But too much sun entering your skin can destroy folic acid, a vitamin that's very important for preventing skin cancer and birth defects. That would put people at a disadvantage and is probably the reason why the red hair gene didn't arise in more tropical places.

Of course, in wealthier regions on Earth, none of this is very important now that we have fortified our milk with vitamin D and our breads with folic acid. Not to mention sunscreen and multi-vitamin pills!

Really, scientists don't see any drawbacks or benefits that currently affect the survival of the red hair gene in some significant way. This is why it will probably keep circulating in the population. Your chances of survival and reproduction are about the same, whether you carry the gene or not.

So, would preserving your eggs help keep red hair alive? First off, your eggs are only half of the equation. Since you are a redhead, chances are that you have two copies of the red hair gene. But you can pass on only one to your children. The other one would have to come from the father. He needs to be at least a carrier of the red hair gene.

This really isn't all that different from the situation people will find themselves in 2100 (or whenever we stop seeing redheads very often). There will still be carriers around, and they could get linked up to have redheads as children.

Let's imagine you succeeded in finding a carrier of the red hair gene as father, and created red haired children. Why wouldn't this help the long-term survival of red hair?

The reason is that you don't really increase the proportion of carriers for the gene. In other words, just a few more redheads in the world are not able to make enough of a difference. One would have to increase the overall frequency of the red hair gene much more dramatically in order for red hair to sustain itself.

How could the frequency of the red hair gene rise? Imagine that being a natural redhead becomes all the rage. If this happens, the number of redheads could grow in at least a couple of ways.

By 2100, we'll probably all know our DNA pretty well. This will mean that carriers of red hair will know they are carriers and can find each other. They could then choose the embryos that will have red hair.

Another possibility is that by then, we may be able to select some of our traits. If it is allowed, people may be able to choose to have kids with red hair and modify their DNA. This would artificially increase the frequency of the red hair gene in the population.

So really, it depends on what you want to accomplish with your eggs. Would you like to help red hair survive in the long-term? Preserving eggs probably wouldn't help. Would you like to make sure your fiery locks won't disappear from your family just yet? That seems more achievable.

Perhaps you will be satisfied with the idea that the red hair gene will not die out just yet, and that redheads, while very rare, will probably still turn up. Or you could hope that genetic technologies will advance enough to let us choose our hair color.

Maybe you can take solace in the fact that redheads are not the only ones who see their numbers dwindle. There's talk that the days of blonde hair and blue eyes are numbered as well...

By Simone Marticke

Redheads are here to stay although they will get rarer. 

Each twin has the MC1R gene. But both of the redhead's genes have mutations.

Red hair versions will almost certainly stay in the human population forever.