Scientists decode butterfly puzzle

WASHINGTON — Scientists have cracked the code of how butterflies get their wing patterns, according to a study published recently in the scientific magazine Proceedings of the National Academy of Sciences.

Arnaud Martin, an evolutionary geneticist at George Washington University in the United States and one of the authors of the study, said the work will help scientists understand fundamental rules about the function of genes.

Butterfly wings vary in color and shape and have different functions. Some butterflies have brightly-colored wings to warn predators that they are poisonous. Others have dull camouflage wings, enabling them to pass off as leaves or bark.

Martin and his colleagues used CRISPR, a system that has been likened to cellular cut-and-paste, to delete a gene called WntA in a broad breed of butterflies, The Washington Post reported on Tuesday.

The small modification led to big changes. For example, in Heliconius butterflies, a species with dramatic colors, a large red spill appeared on the wings of the mutant insects.

Other changes included color splotches and different tints along the edge of the wings.

“It’s extraordinary that it works so broadly,” said Owen McMillan, a staff scientist at the Smithsonian Tropical Research Institute and a co-author of the study.

The researchers knew WntA is important for wing patterns. However, they were surprised that its removal could lead to such dramatic changes.

The research highlights the flexibility of evolution regulation. Carolina Concha, a biogenomics researcher at the Smithsonian and another author of the study, called it “extraordinary”.