In the White Sands National Park of New Mexico, there are three species of small lizard that all share white complexions. In the dark soil of the surrounding landscapes, all three lizards wear coloured coats with an array of hues, stripes and spots. Colours would make them stand out like a beacon among the white sands so natural selection has bleached their skins. Within the last few thousand years, the lesser earless lizard, the eastern fence lizard and the little striped whiptail have all evolved white forms that camouflage beautifully among the white dunes.
Erica Bree Rosenblum from the University of Idaho has found that their white coats are the result of changes to the same gene, Mc1r. All of these adaptations arose independently of one another and all of them reduce the amount of the dark pigment, melanin, in the lizards' skin. It's a wonderful example of convergent evolution, where the same environmental demands push different species along the same evolutionary paths. But Rosenblum has also found that there are many ways to break a gene.
