Occurrence of Noxes in the phylogenetic tree. A schematic phylogeny of organisms was created from genomic information [49, 53, 67, 91]. Branch lengths are not proportional to divergence. "Mammals" in this figure include H. sapiens, C. familliaris, R. norvegicus, and M. musculus. Among fungi, yeast (S. pombe and S. cerevisiae) lacked Noxes, although they did possess a protein with similar structural domains, Fre (see Additional file 9). The asterisk indicates an apparent lack of EF-hand-containing Nox/Duox in two fungi; M. grisea, F. graminearum possess an EF-hand-containing Nox, whereas P. anserina and A. nidulans do not.