Two Genes, 120 Million Years: Repeating Mimicry in Butterflies and Moths

A study of neotropical butterflies and a day-flying moth shows that the same two genes, ivory (a long noncoding RNA) and optix (a transcription factor), underlie similar wing color patterns across species separated by over 120 million years, with regulatory changes near ivory driving the variation. In the moth Chetone histrio, a chromosomal inversion including ivory mirrors a butterfly inversion, suggesting recurrent use of a shared genomic toolkit that constrains evolutionary pathways and could help predict responses to environmental change.