The genes linked to red hair

Scientists have discovered eight genes linked to red hair. The study – which also sheds light on blondes and brunettes – is the largest genetic study of hair colour to date.

It had been thought that red hair is controlled by a single gene, called MC1R. The new research sheds light on other genes that are involved. Previous studies had shown that redheads inherit two versions of the MC1R gene that leads to red hair – one from their mum and one from their dad.

Although almost everyone with red hair has two copies of the red-haired version of MC1R, not everyone carrying two red-haired versions is a redhead. Scientists knew there must be other genes involved but these have mostly remained a mystery until now.

Now researchers at the University of Edinburgh have looked at DNA from almost 350,000 people who had taken part in the UK Biobank study. The study, which was led by The Roslin Institute and the MRC Human Genetics Unit, focused on people of European descent because they have greater variation in hair colour.

The genetics of hair colour and texture

Comparing redheads to people with brown or black hair, they identified eight previously unknown genetic differences that are associated with red hair. The team also looked at the functions of the genes they identified and found that some of them work by controlling when MC1R is switched on or off.

In addition to the redhead genes, the researchers uncovered differences in almost 200 genes associated with blondes and brunettes. Scientists say there is a gradient of colour from black, through dark brown to light brown and blonde, which is caused by increasing number of genetic differences in these 200 genes.

The researchers were surprised to find that many of these 200 genetic differences were associated with hair texture rather than pigmentation. Others are involved in determining how the hair grows – whether curly or straight, for example.

The study, published in the journal "Nature Communications", was funded by the UK's Medical Research Council (MRC) and the Biotechnology and Biological Sciences Research Council (BBSRC).

We were able to use the power of UK Biobank, a huge and unique genetic study of half a million people in Britain, which allowed us to find these effects.

We are very pleased that this work has unravelled most of the genetic variation contributing to differences in hair colour among people.

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

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