and Again: the Repeated Use of Two Mimicry Hotspot Loci

The extent to which evolution is repeatable has been a debated topic among evolutionary biologists. Although rewinding the tape of life perhaps would not lead to the same outcome every time, repeated evolution of analogous genes for similar functions has been extensively reported. Wing phenotypes of butterflies and moths have provided a wealth of examples of gene re-use, with certain 'hotspot loci' controlling wing patterns across diverse taxa. Here, we present an example of convergent evolution in the molecular genetic basis of Batesian wing mimicry in two butterfly species. We show that mimicry is controlled by variation near , a known butterfly hotspot locus. By dissecting the genetic architecture of mimicry in and , we present evidence that distinct non-coding regions control the development of white pattern elements in the forewing and hindwing of the two species, suggesting independent evolution, and that no structural variation is found at the locus. Finally, we also show that orange coloration in is associated with a well-known patterning gene. Overall, our study once again implicates variation near the hotspot loci and in butterfly wing mimicry and thereby highlights the repeatability of adaptive evolution.