Ed Yong reports on a study of pigmentation evolution in the lizards of White Sands, New Mexico: "Three desert lizards evolve white skins through different mutations to the same gene".
The gene is MC1R, also responsible for pigment variation in humans and, apparently, Neandertals. That makes for an interesting story of parallelism of pigment loss. Cave fish have recurrently lost pigmentation due to a different gene, homologous to our OCA2, best known as the "blue-eye" gene. It makes me wonder why lizards broke MC1R repeatedly -- were they using their OCA2 for something else?