Loss of hair colour may be unwelcome to some, but the processes that produce it could be protecting us from damaged DNA (Image: Colin Davis)

GREY hair may be unwelcome, but the processes that produce it are now better understood and could be protecting us from cancer.

Cells called melanocytes produce the pigments that colour hair and their numbers are kept topped up by stem cells. Hair goes grey when the number of stem cells in hair follicles declines. Now Emi Nishimura of Tokyo Medical and Dental University in Japan and colleagues have found what causes this decline in mice. …