Conservatism and novelty in the genetic architecture underlying the diversity of Heliconius wing patterns. (a) Known genetic architectures underlying pattern diversity throughout the clade mapped onto an unscaled phylogeny. Orange tree branches represent nine of the ten species in the silvaniform clade. Major colour variation loci are located on four chromosomes (top) and control variation in similar wing regions (arrows) throughout the genus. Wing phenotypes are represented based on Holzinger and Holzinger (1994). Note that the effect of the Br locus in H. cydno is shown on the ventral side. Loci with names in brackets were described based exclusively on interspecific crosses. (b) Comparative diagram of the distribution of the gene effects across the wing for toolkit loci in the silvaniform clade (excepting H. numata; left) and in the H. melpomene and H. erato clades (right), showing the general conservatism of the regions affected by homologous elements of the multilocus architecture despite some flexibility.