The phylogeny of Or gene family in 12 Drosophila species. Clades with the same color are the orthologous genes with nearby labels. Internal nodes with high bootstrap support (>90%) were marked by solid squares and these with moderate support (>70%) were marked by empty cycles. Branches within orthologous genes are not marked because they nearly always have high bootstrap supports. The phylogeny is rooted using Or83b. The branch length is not in proportion to the actual genetic distance.