Construction of neighbor-joining tree based on amino acid sequences of PRLs. Bootstrap values are indicated for each node. Taxonomic groups are indicated on the right. Prolactin sequences from A. melanopus (AEB00558), Epinephelus coioides (AAO11695), Acanthopagrus schlegeli (AAX21764), Pagrus major (BAE43854), Rhabdosargus sarba (ABB17072), Sparus aurata (AAC26852), Takifugu rubripes (NP_001072092), Oncorhynchus keta (CAA45407), Danio rerio (NP_852102), Anguilla japonica (AAO17792), Tetraodon nigroviridis (AAR25696), Salmo salar (NP_001117140), Carassius auratus (AAT74865). Hypophthalmichthys nobilis (CAA43383), and Anguilla anguilla (CAA48902) were used for comparison. Prolactin sequences from Papio hamadryas (ADG56475) and Homo sapiens (AAH88370) were included as outgroups.