Nucleotide and putative amino acid sequences of leptin in darkbarbel catfish. Numbers on both sides represent the positions of the nucleotide and amino acid sequences. Signal peptide is marked with white type in black box. Four putative α-helix domains are boxed and numbered with helix A-D. Small letters in the top and bottom positions represent the 5′- and 3′-untranslated regions (UTRs). Underlines represent initiation codon and termination codon respectively.