Zoolog Sci. 2010 Feb;27(2):128-33. doi:10.2108/zsj.27.128.

Oikopleura dioica alcohol dehydrogenase class 3 provides new insights into the evolution of retinoic acid synthesis in chordates.

Cañestro C, Albalat R, Postlethwait JH.

Adh3 is the only MDR-Adh in the Oikopleura genome. It strictly conserves the eight residues that constitute the signature of all Adh3 and other residues as well, therefore probably metabolising the same types of substrates as in other species. (Adh3 is the ancestral MDR-Adh genes in vertebrates; Adh1, 2 and 4 show signs of neofunctionalisation).