A single master regulatory gene optix underlies both color and iridescence in butterflies. A single master regulatory gene optix underlies both color and iridescence in butterflies

It is debated to what extent individual regulatory genes might underlie non-gradualistic evolution of complex morphological traits. We have shown that a single regulatory gene, optix, is required for development of all color and iridescence in nymphalid butterfly wings by CRISPR/Cas9 genome editing. To investigate how wing features are controlled by optix, we used mRNA-seq to compare transcript abundance in wild type and optix knockout wings of V. cardui and J. coenia. We generated an average of 269 million reads 36 bp paired-end Nexseq 500 reads from 16 libraries and identified numerous candidate genes including known genes involved in the insect melanin and ommochrome biosynthetic pathways and suspected components potential involved in scale structure. Overall design: Butterfly forewings and hindwings were sampled separately at a late stage of pupal development when ommochrome and melanin pigments are both becoming visible, with two biological replicates each of both wild type and knockout phenotypes, using Illumina Nextseq 500 for 36 bp paired end sequencing.