A team of researchers from various universities has discovered that the gene that allows tropical butterflies to mimic each others' patterning is the same one that pushed British moths to turn black during the industrial revolution.
Known as "cortex," the findings from the University of Cambridge and the University of Sheffield suggest that this fast-evolving gene is a key player in determining the colors and patterns on butterfly wings.
In a parallel paper from the University of Liverpool, the findings suggest that the cortex gene is also the cause of the peppered moth's change to black during the industrial revolution in an attempt to camouflage itself amongst the dark-colors of the mid-19th century.
Taken together, these findings offer insight into the role of genetics in evolution, although the researchers have yet to determine how the cortex gene came to be selected in the determination of wing color and patterning.
"What's exciting is that it turns out to be the same gene in both cases," said Chris Jiggins of the University of Cambridge. "For the moths, the dark coloration developed because they were trying to hide, but the butterflies use bright colors to advertise their toxicity to predators. 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?"
"It's amazing that the same gene controls such a diversity of different colors and patterns in butterflies and a moth," added Nicola Nadeau of the University of Sheffield. "Our study, together with the findings from the University of Liverpool, shows that the cortex gene is important for color and pattern evolution in this whole group of insects."
Over the years, butterfly wing patterns were adapted for various purposes, including wing patterns, thermal regulation and camouflage. Although these patterns have been studied intensely for over a century, the underlying molecular mechanisms behind them are only starting to be understood.
"Our results are even more surprising because the cortex gene was previously thought to only be involved in producing egg cells in female insects, and is very similar to a gene that controls cell division in everything from yeast to humans," Nadeau added.
The findings were published in the June 1 issue of the journal Nature.
