Be blonde or brunette at the flick of a DNA switch

Whether you are born blonde or brunette depends on a single letter of the genetic code, scientists have learned. The DNA switch fine-tunes the activity of a gene known to be linked to hair colour.

Changing just one of its chemical components — a single genetic code element — is enough to generate blonde hair.

“This particular genetic variation in humans is associated with blonde hair, but it isn’t associated with eye colour or other pigmentation traits,” said the lead researcher, David Kingsley, from Stanford University in the US.