Red hair is most common in Ireland

Robin McKie:

Red hair today is generally associated with the Scots and Irish, but there have been no consistent efforts to establish the prevalence of the condition.

“It has actually become harder to find the prevalence of red hair today,” said Rees. “More and more women — and some men — now dye their hair and we simply have no idea if a redhead is a real one or if a blonde is a redhead under the dye. As a result the incidence of red hair in Britain is still a bit of a mystery.”

Enter the scientists of the People of the British Isles project: thanks to their efforts, this most distinctive characteristic is now opening up its mysteries for the first time. Testing their white cell samples for two of the half-dozen red-hair versions of the MC1R gene, they were able to show their frequency in each area of the British Isles. The results were intriguing.

Where one is the maximum value, they got figures of 0.16 and 0.23 for the frequencies of red-hair genes in Cornwall and Devon. The frequency in Oxfordshire was 0.07; in Sussex and Kent 0.13; in northeast England 0.11; in Lincolnshire 0.07; and in Cumbria nil. In Wales the figure was 0.21, and in Orkney a high 0.26. But the highest was in Ireland. Using data from other research studies, the team got a figure for Ireland of 0.31, confirmation of the stereotypical image of the red-haired Irishman.

The results are remarkable, as Sir Walter Bodmer, the Oxford geneticist leading the project, acknowledges: “I was amazed at them. I didn’t expect to see something like this.”

The research gives us, for the first time, an insight into the startling numbers of native people who have been described as having red hair in ancient times.

Here is why red hair is so common in Ireland:

But why do we have such numbers in these parts of the British Isles today and not others? The answer, says Bodmer, is that red-hair genes were common among the first Britons and that populations in the archipelago’s fringes still carry their bloodline.

“Genes for red hair first appeared in human beings about 40,000 to 50,000 years ago,” agrees Rees.

These genes were then carried into the islands by the original settlers, men and women who “would have been relatively tall, with little body fat, athletic, fair-skinned and who would have had red hair”, says David Miles, of English Heritage.

Redheads therefore represent the land’s most ancient lineages. So if you want an image of how those first people appeared, don’t think of a hairy savage with a mane of thick black hair. Contemplate instead a picture of a slim, ginger-haired individual: Prince Harry, perhaps, or the actress Nicole Kidman who has Scottish and Irish descent.

Why did those early Britons have so many redheads in their midst in the first place? Is there an evolutionary advantage to having red hair in this part of the world? According to Rees, the answer may be yes.

The MC1R variants that cause red hair also have an effect on the skin. As a result, redheads do not make enough of the dark pigment melanin to protect them against the sun’s powerful ultraviolet rays. Their skin rarely tans. It just burns or freckles.

In Africa, where modern humans first evolved 150,000 years ago, this would have been fatal. In northern Europe, however, melanin-free skin could have provided an advantage because we make vitamin D in our skin when sunlight shines on it.

Dark-skinned people were protected against the African sun, but their ability to make vitamin D would have been badly affected in relatively gloomy northern Europe. This could have caused rickets, resulting in weak bones and curved legs — bad news for a hunter-gatherer. Rickets is particularly damaging for women, as it increases pelvic deformations, raising the risk of death in childbirth. So, the theory goes, we evolved white, melanin-free skin that has no dark pigment to block sunlight and cause rickets. Red hair was a side effect.

So there it is: being a redhead could mean you possess an evolutionary advantage over non-red-haired people.

Genetic differences between Britain and Ireland