Maximum likelihood phylogenetic tree of all zebrafish and human CYPs. The phylogeny is rooted with CYP51, the only vertebrate CYP shared with fungi. Clans, as defined by Nelson (2003), are indicated by shaded highlights (red, Clan2; blue, Clan3; green, Clan4; purple, Mitochondrial Clan). The CYP2 family is further highlighted in yellow (see also Figure 2). Support values in the branches are derived from 100 bootstrap replicates using RAxML. Human (hs) sequences are red, zebrafish (zf) are blue.