In general, the tree shows six distinct monophyletic
clades, all but one supported by posterior probabilities of
1.00. These include the mitochondrial, CYP2, CYP3, and
CYP4 clans, and two deep branches that do not include
any arthropod CYPs. The non-arthropod lineages are
nearly deuterostome exclusive and would be if not for the
two anemone CYPs that show their closest relationships
to CYP26. These anemone CYPs found nested within a
vertebrate lineage indicate that a CYP26-like ancestor may
have existed in cnidarians but was lost in protostomes.
Similar inferences concerning CYP loss in protostomes
have already been made about CYP51, CYP20 and possibly
CYP7. The history of CYP20 in protostomes may be
complex since an ortholog has been detected in the annelid
leech Haementeria depressa (CN807321). In addition,
CYP19 (aromatase) clusters with the CYP2 and mitochondrial
clans, and CYP46 and related sea anemone CYPs are
part of a sister clade to the CYP4 clan (Additional file 2).