Wing patterning gene redefines the mimetic history of Heliconius butterflies

The mimetic butterflies Heliconius erato and H. melpomene have undergone parallel radiations to form a near-identical patchwork of over 20 different wing pattern races across the Neotropics. Previous molecular phylogenetic work on these radiations has suggested that similar but geographically disjunct color patterns arose multiple times independently in each species. The neutral markers used in these studies, however, can move freely across color pattern boundaries and therefore might not represent the history of the adaptive traits as accurately as markers linked to color pattern genes. To assess this, we compared relationships among races within H. erato and within H. melpomene using a series of unlinked genes, genes linked to color pattern loci, and optix - a gene recently shown to control red color pattern variation. We found that while unlinked genes partition populations by geographic region, optix had a different history, structuring lineages by red color patterns and supporting ...