Divergence of Grainy head affects chromatin accessibility, gene expression, and embryonic viability in .

Pioneer factors are critical for gene regulation and development because they bind chromatin and make DNA more accessible for binding by other transcription factors. The pioneer factor Grainy head (Grh) is present across metazoans and has been shown to retain a role in epithelium development in fruit flies, nematodes, and mice despite extensive divergence in both amino acid sequence and length. Here, we investigate the evolution of Grh function by comparing the effects of the fly () and worm () Grh orthologs on chromatin accessibility, gene expression, embryonic development, and viability in transgenic .

Divergent expression of aristaless1 and aristaless2 during embryonic appendage and pupal wing development in butterflies.

Background: Gene duplication events are critical for the evolution of new gene functions. Aristaless is a major regulator of distinct developmental processes. It is most known for its role during appendage development across animals.

aristaless1 has a dual role in appendage formation and wing color specification during butterfly development.

Background: Highly diverse butterfly wing patterns have emerged as a powerful system for understanding the genetic basis of phenotypic variation. While the genetic basis of this pattern variation is being clarified, the precise developmental pathways linking genotype to phenotype are not well understood. The gene aristaless, which plays a role in appendage patterning and extension, has been duplicated in Lepidoptera.

Aristaless Controls Butterfly Wing Color Variation Used in Mimicry and Mate Choice.

Neotropical Heliconius butterflies display a diversity of warningly colored wing patterns, which serve roles in both Müllerian mimicry and mate choice behavior. Wing pattern diversity in Heliconius is controlled by a small number of unlinked, Mendelian "switch" loci [1]. One of these, termed the K locus, switches between yellow and white color patterns, important mimicry signals as well as mating cues [2-4].