Number of redheads surges in Europe – and scientists don’t know why

Redheads who were teased in the school playground now have the last laugh – as a study reveals their numbers are surging thanks to natural selection.

Researchers have found that humans are still evolving, and at a much faster rate than previously realised.

DNA analysis shows that over the past 10,000 years, the ginger gene has become more common among Europeans.

It means the red hair sported by Ed Sheeran, Prince Harry, and Florence Welch could increasingly become more widespread.

Other variants that appear to have been ‘selected’ for include a light skin tone, a lower chance of male–pattern baldness, a faster walking pace and higher intelligence.

Additional traits that have become more common are a susceptibility to celiac disease, immunity to HIV, resistance to leprosy, a lower risk of rheumatoid arthritis and a lower body fat percentage.

The researchers, from Harvard University, aren’t completely sure what survival advantage red hair may have in modern times.

‘Perhaps having red hair was beneficial 4,000 years ago,’ they said. ‘Or perhaps it came along for the ride with a more important trait.’

The findings challenge conventional theories that humans have changed little in evolutionary terms since we first emerged 300,000 years ago.

For the study, the researchers analysed ancient DNA from nearly 16,000 people across more than 10,000 years in West Eurasia – which is now Europe and parts of the Middle East.

They collaborated with more than 250 archaeologists and anthropologists to sift through the DNA.

Overall, they found that most of the genetic selection accelerated after the introduction of farming, reflecting how different traits became advantageous as people shifted to agriculture from hunting and gathering.

Some of the changes seem logical – for example developing a resistance to certain diseases.

But others appear counterintuitive, like the major genetic risk factor for gluten intolerance spiking after people began farming wheat.

‘With these new techniques and large amounts of ancient genomic data, we can now watch how selection shapes biology in real time,’ first author Ali Akbari, from Harvard University, said.

‘Instead of searching for the scars natural selection leaves in present–day genomes using simple models and assumptions, we can let the data speak for itself.’

Genetic quirks are usually the result of random mutations that occur during errors in copying parents’ DNA during reproduction.

Most mutations hardly have any impact, but if one provides some kind of survival advantage then the carrier is more likely to live longer and pass on the variant to their children.

Over generations, the most advantageous variants can become dominant across a whole species, driving evolution via natural selection.

‘This work allows us to assign place and time to forces that shaped us,’ Harvard Geneticist David Reich said.

The authors, who published their work in the journal Nature, plan to repeat the research in East Asia, East Africa and Central and South America to uncover yet more genetic variations.

They hope this could help with disease prevention and pave the way for developing new gene therapy medications.

‘To what extent will we see similar patterns in East Asia or East Africa or Native Americans in Mesoamerica and the central Andes?’ Professor Reich asked.

‘If we can’t use ancient DNA to study the most important period in human evolution one million to two million years ago, then at least we can study selective pressure on human genomes during more recent periods of change and learn broader principles.’

Despite the findings, redheads are still relatively rare – making up less than 2 per cent of the global population.

A previous study found that red–headed women have genetically different pain thresholds to the rest of the female population.

A report in the medical journal Anesthesiology said redheads’ pain thresholds were linked to the hair gene mutation which partially switches off a sensory receptor.

They also have the highest orgasm rates of all hair types, experts found.

‘The sex lives of women with red hair were clearly more active than those with other hair colour, with more partners and having sex more often than the average,’ Dr Werner Habermehl, from the University of Hamburg, said.

‘The research shows that the fiery redhead certainly lives up to her reputation.’