He later admitted that it was not as accurate as it could be, but it was in line with popular belief. And that belief remains. That red hair is more common in Scotland than anywhere else in the world.
Such a belief forces us to ask ourselves, “What is the cause of red hair?” And then to consider whether it is really more common in Scotland.
To answer these questions, we must begin by looking at the line of genetics to see why red hair and blonde hair are common in European populations but rare elsewhere.
This trend is almost certainly a side effect of yellow-skinned Europeans, beginning with the natural selection of genetic mutations among the first prehistoric immigrants from Africa, whose skin was black.
This migration meant that poor skin in Europe with darker skin produced less vitamin D, so genetic mutations favored providing lighter skin. Many genes that affect skin color also affect hair color, so in many cases yellow hair growth results in red or blonde hair.
Redheads Rally for Ginger Pride in Edinburgh
One of these genes, called MC1R, is known to be a major cause of red hair. Almost all red-haired people have inherited two genetic variants of MC1R, one from each parent. However, not everyone has red hair with the two types of genes, and many other genes affect whether your hair will be red.
By looking at the changes in a person’s genes, we can estimate whether they will have red, blonde or black hair.
The UK Biobank is a study of half a million people, where their diverse characteristics are recorded, and genetic mutations are analyzed. In one question, participants were asked about the natural color of their hair. While anonymous, a note of where each person was born allows us to find out from the results if there really are more redheads in Scotland.
The results show that our clutch is indeed true. Although a relatively rare feature, only six percent or less of those surveyed had about 50 percent more red hair in the north of Gretna than in the south of England.
More specifically, we can see that the farther north you are born, the more likely you are to have red hair. Furthermore, if we look at each person’s genetic variation and use it to calculate the probability of their having red hair, we see it growing as the birthplace moves north.
Yet, while our stereotype is supported by science, it is proudly reinforced. With northerners and northerners born with the same genetic makeup, and probably the same hair color, Scots seem to be more likely to celebrate their amber flair, keeping the tradition alive.
Emeritus Professor Ian Jackson is a former head of the disease mechanism at the Institute of Genetics and Cancer at the University of Edinburgh and a colleague of the Royal Society of Edinburgh. This article expresses their own views. RSE is Scotland’s national academy, bringing together great minds to contribute to Scotland’s social, cultural and economic well-being. Find out more at rse.org.uk And RoyalSocEd.