Scientists at the University of Edinburgh say the discovery of the additional genes linked to red hair has helped to solve the mystery of how redheads inherit their flaming locks.
The study - which also sheds light on blondes and brunettes - was the largest genetic study of hair colour to date.
While only around 1-2 per cent of the population possesses the ginger gene, around 13 per cent of Scots have red hair. Famous flame-haired Scots include actress Karen Gillan and singers Annie Lennox and Lulu, while even the ancient Romans described the Celts as redheads.
Until now it was thought that their red hair was controlled by a single gene, called MC1R. Previous studies had shown that redheads inherit two versions of the MC1R gene that leads to red hair – one from each of their parents.
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.
Researchers at the University of Edinburgh have identified eight previously unknown genetic differences associated with red hair.
Professor Ian Jackson, of the Medical Research Council Human Genetics Unit at the University of Edinburgh, said: “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.” Professor Albert Tenesa, of the University of Edinburgh’s Roslin Institute, said: “We are very pleased that this work has unravelled most of the genetic variation contributing to differences in hair colour among people.”