Molecular taxonomy of the Nox domains of Nox/Duox proteins. Amino acid sequences of the following species were trimmed to the length corresponding to human Nox2 and were aligned: human-Hs, H. sapiens; Cow-Bt, B. Taurus; dog-Cf, C. familliaris; rat-Rn, R. norvegicus; mouse-Mm, M. musculus; opossum-Md, M. domestica; chicken-Gg, G. gallus; frog-Xt, X. tropicalis; zebrafish-Dr, D. rerio; fugu-Tr, T. rubripes; tetraodon-Tn, T. nigroviridi s; medaka-Ol, O. latipes; ascidian-Ci, C. intestinalis; sea urchin-Sp, S. purpuratus; fruit fly-Dm, D. melanogaster; mosquito-Ag, A. gambiae; honeybee-Am, A. mellifera; nematode-Ce, C. elegans; plant-At,A. thaliana; amoeba-Dd, D. discoideum; fungus-Pa, P. anserina, fungus-An, A. nidulans; fungus-Mg, M. grisea; fungus-Fg, F. graminearum; alga-Cc, C. crispus; and alga-Py, P. yezoensis. Each subfamily is indicated by a colored circle, and bootstrap values of 1,000 replications are shown at the major branches as percentages. Evolutionary distances (inferior bar) are equivalent to 0.1 amino acid substitution per site.