The presence of similar colour patterns among different species of poisonous butterflies has intrigued scientists for 150 years. How is that they evolved to mimic one another’s delicate colour patterns, actually joining forces to warn predators to keep away?
Now a research team led by Robert Reed, assistant professor of ecology at the University of California, Irvine, has identified a single gene called optix, responsible for red wing colour patterns in passion vine butterfly species.
“This is our first peek into how mimicry and convergent evolution happen at a genetic level.
“We discovered that the same gene controls the evolution of red colour patterns across remotely related butterflies,” said Reed, according to the journal Science.
“This is in line with emerging evidence from various animal species that evolution generally is governed by a relatively small number of genes,” a California statement quoting Reed said.
The scientists spent several years crossbreeding and raising the delicate butterflies in large netted enclosures in the tropics so they could map the genes controlling colour pattern.
Postdoctoral researcher Riccardo Papa, now an assistant professor at the University of Puerto Rico, and Reed’s colleague, then perfected a way to analyse the genome map by looking at gene expression in micro—dissected butterfly wings.
Finding a strong correlation between red colour patterns and gene expression in one small region of the genome was the breakthrough that led to discovery of the gene.