The New York Times summarizes two recent papers on melanomas, the most dangerous type of skin cancer, that provide strong evidence that such cancers start not with mutations in genes, but mutations in the DNA regions that control them. The vast majority of our human genetic code comprises of these and other non-coding regions of DNA; what was once dismissed as mostly ‘junk DNA’ might be better called ‘dark matter’, considering how much we still have to learn about their function.