Genomic architecture and functional unit of mimicry supergene in female limited Batesian mimic butterflies.

It has long been suggested that dimorphic female-limited Batesian mimicry of two closely related butterflies, and is controlled by supergenes. Whole-genome sequencing, genome-wide association studies and functional analyses have recently identified mimicry supergenes, including the gene. Although supergenes of both the species are composed of highly divergent regions between mimetic and non-mimetic alleles and are located at the same chromosomal locus, they show critical differences in genomic architecture, particularly with or without an inversion: . has an inversion, but . does not. This review introduces and compares the detailed genomic structure of mimicry supergenes in two species, including gene composition, repetitive sequence composition, breakpoint/boundary site structure, chromosomal inversion and linkage disequilibrium. Expression patterns and functional analyses of the respective genes within or flanking the supergene suggest that and other genes are involved in mimetic traits. In addition, structural comparison of the corresponding region for the mimicry supergene among further species suggests three scenarios for the evolution of the mimicry supergene between the two species. The structural features revealed in the mimicry supergene provide insight into the formation, maintenance and evolution of supergenes. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.