DNA testing

Largest ever hair DNA test unravels redhead mystery

With redheads making up approximately 1-2% of the world’s population, there’s been much intrigue into how individuals inherit their distinctive locks. It had previously been thought that the inheritance of a single recessive gene controlled whether or not a person would inherit red hair. However, the process has been unravelled and eight genes linked to red hair have been discovered by Edinburgh University researchers in the largest genetic study of hair colour to date. In all, DNA tests were performed on almost 350,000 people who had taken part in the UK Biobank study.

The hypothesis had been that red hair was controlled by a single gene, MC1R. Previous studies have shown that people with red hair inherit two versions of the MC1R gene, one from each biological parent. However, not everyone carrying these two MC1R versions will automatically become a redhead, which means that other genes had to be involved.

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When the redheads were compared with people with brown or black hair, scientists identified eight previously-unknown genetic differences. When the functions of the genes were investigated, it was discovered that some of them work by controlling when MC1R is switched on or off.

The researchers also uncovered differences in almost 200 genes associated with blondes and brunettes. One of their most unexpected findings was the fact that many of these genetic differences affect hair texture, rather than colour. The study has been published in Nature Communications.

Commenting on the research, Professor Albert Tenesa, of the University’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”. For further information on AlphaBiolabs’ DNA testing services, please call us on 0333 600 1300 or email customerservices@alphabiolabs.com

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