Phylogeny of insect GMC oxidoreductases. The phylogeny was generated using the neighbor-joining method with Poisson correction and bootstrap replicates 500 times. Bootstrap values are shown at nodes. Based on the phylogeny, genes were classified into gene subfamilies (see text). A Greek letter in a sequence name is shown in a Roman alphabet in this figure (e.g., A for α). Abbreviations: Dm (D. melanogaster), Ag (A. gambiae) Am (A. mellifera), Tc (T. castaneum), Ecol (Escherichia coli), Cele (Caenorhabditis elegans), Anig (Aspergillus niger), Aory (Aspergillus oryzae), Pama (Penicillium amagasakiense), EO (ecdysone oxidase), and CHD (choline dehydrogenase). "DmEO_B1" (CG9504) belongs to GMCβ, but it is indicated as EO instead of GMC because its functional identity is known. The number with 4 or more digits (e.g., CG9503, XM961446) indicates GenBank accession number of the sequence (detailed sequence information is in Additional File 7). "iso1-4" of GMCβ4 indicates four isoforms of this gene (see Figure 5). All protein sequences used in this study are in Additional File 8.