How do redheads inherit their ginger locks? Scientists uncover the truth in largest ever DNA hair study

It was previously believed that a single gene determined whether or not a person would inherit ginger hair

(Getty)

With redheads making up approximately one to two per cent of the world’s population, there’s been much intrigue into how individuals with flame-coloured hair inherit their ginger locks.

While it's previously been believed that the inheritance of a single recessive gene controls whether or not a person will inherit ginger hair, a new study has uncovered several formerly unidentified genes that are also involved.

In what’s been described as the “largest genetic study of human hair colour”, a team led by scientists at Edinburgh University carried out an investigation using data from the UK Biobank study.

The scientists assessed DNA from almost 350,000 individuals, comparing the DNA of people with ginger hair to those with blonde, brunette and black hair.

It was formerly understood that the MC1R gene determined whether or not a person would be a redhead.

Jessica Chastain at the 23rd Annual Critics' Choice Awards on 11 January 2018 (Getty Images)

However, when comparing redheads to those with brunette or black hair, the scientists were able to identify eight genetic differences connected with redheads that they hadn’t detected before.

The study, which was published in the journal Nature Communications, solely assessed individuals with European heritage, due to the greater variability of hair colour among them.

Previous studies have shown that people with ginger hair inherit two versions of the MC1R gene, one from each of their biological parents.

However, not everyone who carries two versions of the MC1R gene will automatically become a redhead.

With this in mind, scientists were aware that there had to be other genes also involved, but until now didn't know what they were.

When taking a closer look at the functions of the newly discovered genetic variants, the researchers came to the conclusion that some of them are able to determine when the MC1R gene is switched on or off.

Julianne Moore at the Chanel Haute Couture Fall/Winter 2017-2018 on 4 July 2017 (Getty Images)

Melanie Welham, executive chair of the Biotechnology and Biological Sciences Research Council that helped to fund the research, has spoken about the study's fascinating findings.

"Once again, collaborative research is helping to provide answers to some of life's important questions," she says.

"BBSRC is pleased to have helped support the largest genetic study of human hair colour.

"It has provided some fascinating insights into what makes us such distinct individuals."

In addition to the discovery of the eight genetic differences associated with ginger hair, the scientists also found almost 200 genes linked to blonde and brunette hair.

One of their most unexpected findings was the fact that many of these genetic differences affect hair texture, rather than colour.

On 5 November 2018, people in the US celebrated National Love Your Red Hair Day.

The day is an annual celebratory event that was created with the aim of making people who have ginger hair feel empowered and confident.