SEQUENCE OF THE GROWTH-HORMONE (GH) GENE FROM THE SILVER CARP (HYPOPHTHALMICHTHYS-MOLITRIX) AND EVOLUTION OF GH GENES IN VERTEBRATES

The silver carp (Hypophthalmichthys molitrix) growth hormone (GH) gene was isolated and sequenced following amplification from genomic DNA b y the polymerase chain reaction. The gene spans a region of approx. 2. 5 kb nucleotides (nt) and consists of five exons. The sequence predict s a polypeptide of 210 amino acids (aa) including a putative signal pe ptide of 22 hydrophobic aa residues. The arrangement of exons and intr ons is identical to the GH genes of common carp, grass carp, and very similar to mammals and birds, but quite different from that for the GH genes of tilapia and salmonids. The silver carp GH gene shares a high homology at the nt and aa levels with those of grass carp (95.3% nt, 99.5% aa) and of common carp (81% nt, 95.7% aa).