Fair-skinned, red-haired folks know — sometimes through painful experience — that they are more susceptible to the damaging effects of the sun's ultraviolet (UV) rays, including sunburn, skin aging and a higher risk of skin cancers. But a study in Nature suggests that in mice, the pigment responsible for this colouring has a role in the development of melanoma.

"There is something about the redhead genetic background that is behaving in a carcinogenic fashion, independent of UV," says David Fisher, a cancer biologist at Massachusetts General Hospital in Boston, who led the study. "It means that shielding from UV would not be enough."

Compared to people with darker skin, those with fair, freckly skin and red hair produce a different form of the pigment melanin. This red–yellow form, called pheomelanin, is less effective at protecting the skin from UV damage than the darker form, eumelanin. The difference is caused by a mutation in the gene MC1R2.

But for a number of years there have been hints that UV exposure alone might not account entirely for the risk of melanoma in redheads.

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