Genome editing in butterflies reveals that spalt promotes and Distal-less represses eyespot colour patterns

Abstract

Transcription factors Distal-less(Dll) and spalt were co-opted during the evolution of butterfly eyespots. Here, Zhang and Reed use CRISPR/Cas9 genome editing to show that while spalt is a positive regulator of eyespots as predicted, Dll knockouts have positive effects on both eyespot size and number, thus suggesting that Dllis an eyespot repressor, not an activator as previously thought.