Unrooted phylogenetic tree of HSD17B predicted protein sequences. We identified nine HSD17B genes in the zebra finch assembly; these predicted proteins segregated with the same enzyme type in chicken and the other species. The unrooted tree models some enzymes (HSD17B4 and 7) as unique branches. Enzyme types predicted to be evolutionarily related (HSD17B3 and 12, and HSD17B2 and 6), are shown to be preserved in the zebra finch. Bootstrap support values are at branch points. Scale bar denotes substitution rate. zf = zebra finch, ch = chicken, h = human, m = mouse, dan = zebrafish, iso = isoform.