Genetic switch that turned moths black also colours butterflies

Heliconius butterflies have evolved bright yellow colours to deter predators, while peppered moths famously turned black to hide from birds. A new study reveals that the same gene causes both, raising fascinating questions about how evolution by natural selection occurs in these species. It raises the question that given the diversity in butterflies and moths, and the hundreds of genes involved in making a wing, why is it this one every time? - Chris Jiggins The same gene that enables tropical butterflies to mimic each other's bright and colourful patterning also caused British moths to turn black amid the grime of the industrial revolution, researchers have found. Writing , a team of researchers led by academics at the Universities of Cambridge and Sheffield, report that a fast-evolving gene known as "cortex" appears to play a critical role in dictating the colours and patterns on butterfly wings. A parallel paper in the same journal by researchers from the University of Liverpool shows that this same gene also caused the peppered moth to turn black during the mid-19th century, when it evolved to find new ways to camouflage itself; a side-effect of industrial pollution at the time. The finding offers clues about how genetics plays a role in making evolution a predictable process. For reasons the researchers have yet to understand in full, the cortex gene, which helps to regulate cell division in butterflies and moths, has become a major target for natural selection acting on colour and pattern on the wings.