Rampant genome-wide admixture across the Heliconius radiation

The pattern of evolution is typically portrayed as a phylogenetic tree, yet gene flow between good species may be an important mechanism in diversification, spreading adaptive traits and leading to a complex pattern of phylogenetic incongruence. This process has thus far been studied mainly among a few closely related species, or in geographically restricted areas such as islands, but not on the scale of a continental radiation. Using genome-wide resequencing of 40 out of 45 species in the genus we demonstrate that admixture has played a role throughout the evolution of most lineages in the charismatic Neotropical butterflies Heliconius.