Holozoan RiBi promoters are enriched in E(CG) sites. The percentage of E(CG)-bearing promoters in RiBi genes is two to four fold higher in D. melanogaster (Dm), H. sapiens (Hs), N. vectensis (Nv), and M. brevicollis (Mb) relative to negative control sequences composed of promoter regions of downstream conserved genes (C1), the 3' regions of RiBi genes (C2), or the promoters of genes with GO mitochondrial classification (C
). This difference between RiBi and C1, C2, or C
is lacking in outgroup genomes such as S. cerevisiae (Sc), which lack Myc, as well as in the nematode genome of C. elegans (Ce), which has secondarily lost Myc (Fig. 3). Inset depicts phylogenetic relationships among these organisms.