THE idea that evolution is an essentially random process has been dealt another blow. When related species independently evolve similar physical traits they tend to use the same genes to do so.
Nature often comes up with similar solutions for a particular problem, a phenomenon known as convergence. For instance, different species of butterflies in the genus Heliconius have evolved similar wing patterns to warn potential predators that they are poisonous, as have the famous monarch and viceroy butterflies. “But we don’t know whether similar butterfly patterns have evolved with changes in the same genes or by different means,” says…
