Unrooted phylogenetic tree of HSD3B predicted protein sequences. The two HSD3B genes identified in the zebra finch genome assembly, HSD3B1 and HSD3B7, show the closest similarity to the same HSD3B types in the chicken. The HSD3B1 protein sequence is predicted to be more similar to the HSD3B1-6 mammalian proteins than the HSD3B7 zebra finch protein is to the mammalian HSD3B7 protein. Bootstrap values are at branch points. Scale bar denotes substitution rate. zf = zebra finch, ch = chicken, h = human, m = mouse, dan = zebrafish.