Genetics of Red Hair & Redheads
2007 Report that Red Hair Would Disappear by 2100 is False
Changes in the MC1R gene that lead to red hair will always be present at a low level in the collective DNA of humanity.
Every now and then a story pops up that redheads are an endangered species. For example, in February 2007 there was a flurry of reports that red hair would be extinct by 2100 based on a statement from the Oxford Hair Foundation. This is nonsense.
Redheads are probably here to stay. They will almost certainly become less common over time, but there will always be a few of them around.
To understand why this is, we need to delve a little into how red hair works at the genetic level. Remember, we have two copies of most of our genes—one from mom and one from dad. For people of European descent, red hair happens when both copies of someone’s MC1R gene doesn’t work properly (this is called a recessive trait).
How to become a redhead?
So to end up a redhead, you need to get a non-working copy of the MC1R gene from both mom and dad. However, most people in the world have two good copies of the MC1R gene and so cannot have red haired kids (although they can have red haired grandkids). The only reason we have as many redheads as we do is because until recently, there was very little mingling of ethnic groups. In other words, people with red hair genes tended to have kids with other people with red hair genes. This is no longer true and is a big reason why so few redheads will be around in the future.
To get a feel for how this intermingling will affect red hair in the human population, let’s imagine that the population of Scotland was uprooted and dispersed throughout China. Scotland has a population of around 5 million and of these, 13% are redheads and 40% have one copy of the MC1R gene that doesn’t work (these folks are said to be carriers for red hair). This means that of the 10 million copies of the MC1R gene that are in Scotland, around 3.3 million don’t work. In our mythical country of Scotland-China, these genes would still be present—just severely diluted. In other words, there would be 3.3 million broken copies of the MC1R gene and 2 billion or so working copies.
Red Hair Odds in the Future
The chances of two red hair carriers having children together would fall from 1 in 2 in Scotland to 1 in 400 in Scotland-China. Which means the percentage of redheads would go from 1 in 8 in Scotland to something like 1 in 640,000 (or 1500 out of 1 billion) in Scotland-China. Rare, but not extinct.
So having red hair will become less and less common over time. And it isn't the only trait doomed to a steep decline. For example, the genetics of blue eyes works very similarly and is really only common in Western Europe. Blue eyes are destined to go the way of red hair too.
