Single master regulatory gene coordinates the evolution and development of butterfly color and iridescence.

The gene has been implicated in butterfly wing pattern adaptation by genetic association, mapping, and expression studies. The actual developmental function of this gene has remained unclear, however. Here we used CRISPR/Cas9 genome editing to show that plays a fundamental role in nymphalid butterfly wing pattern development, where it is required for determination of all chromatic coloration. knockouts in four species show complete replacement of color pigments with melanins, with corresponding changes in pigment-related gene expression, resulting in black and gray butterflies. We also show that simultaneously acts as a switch gene for blue structural iridescence in some butterflies, demonstrating simple regulatory coordination of structural and pigmentary coloration. Remarkably, these knockouts phenocopy the recurring "black and blue" wing pattern archetype that has arisen on many independent occasions in butterflies. Here we demonstrate a simple genetic basis for structural coloration, and show that plays a deeply conserved role in butterfly wing pattern development.

Zhang L ，Mazo-Vargas A ，Reed RD 《-》

Structural color in Junonia butterflies evolves by tuning scale lamina thickness.

In diverse organisms, nanostructures that coherently scatter light create structural color, but how such structures are built remains mysterious. We investigate the evolution and genetic regulation of butterfly scale laminae, which are simple photonic nanostructures. In a lineage of buckeye butterflies artificially selected for blue wing color, we found that thickened laminae caused a color shift from brown to blue. Deletion of the patterning gene also altered color via lamina thickening, revealing shared regulation of pigments and lamina thickness. Finally, we show how lamina thickness variation contributes to the color diversity that distinguishes sexes and species throughout the genus . Thus, quantitatively tuning one dimension of scale architecture facilitates both the microevolution and macroevolution of a broad spectrum of hues. Because the lamina is an intrinsic component of typical butterfly scales, our findings suggest that tuning lamina thickness is an available mechanism to create structural color across the Lepidoptera.

Thayer RC ，Allen FI ，Patel NH 《eLife》

Transcriptome analysis of the painted lady butterfly, Vanessa cardui during wing color pattern development.

Connahs H ，Rhen T ，Simmons RB 《BMC GENOMICS》

optix drives the repeated convergent evolution of butterfly wing pattern mimicry.

Mimicry--whereby warning signals in different species evolve to look similar--has long served as a paradigm of convergent evolution. Little is known, however, about the genes that underlie the evolution of mimetic phenotypes or to what extent the same or different genes drive such convergence. Here, we characterize one of the major genes responsible for mimetic wing pattern evolution in Heliconius butterflies. Mapping, gene expression, and population genetic work all identify a single gene, optix, that controls extreme red wing pattern variation across multiple species of Heliconius. Our results show that the cis-regulatory evolution of a single transcription factor can repeatedly drive the convergent evolution of complex color patterns in distantly related species, thus blurring the distinction between convergence and homology.

Reed RD ，Papa R ，Martin A ，Hines HM ，Counterman BA ，Pardo-Diaz C ，Jiggins CD ，Chamberlain NL ，Kronforst MR ，Chen R ，Halder G ，Nijhout HF ，McMillan WO ... -  《-》

Parallel evolution of ancient, pleiotropic enhancers underlies butterfly wing pattern mimicry.

Lewis JJ ，Geltman RC ，Pollak PC ，Rondem KE ，Van Belleghem SM ，Hubisz MJ ，Munn PR ，Zhang L ，Benson C ，Mazo-Vargas A ，Danko CG ，Counterman BA ，Papa R ，Reed RD ... -  《-》