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Piscidin has a wide range in killing microorganisms including bacteria, fungi, viruses, parasites and has strong anti-tumor activity and plays a role in increasing innate immunity and also does not provide resistance against bacteria; Therefore, it is of great importance in aquaculture. In this study, piscidin gene of Sparus aurata in vector pTZ57R / T was cloned. In this research, ligation product was transferred to component cell of E. coli DH5α strain. Plasmid extraction was performed from single colonies observed in ampicillin plate. Confirmation of the accuracy of single colonies grown in this research was performed by direct PCR and sequencing. The amplified cDNA fragment of the gilthead seabream piscidin gene consists of 310 nucleotides and 57 amino acids. The results of this research show that piscidin gene has been successfully cloned in pTZ57R / T vector. Comparison of nucleotide sequence of piscidin gene in this study showed high similarity with piscidin 5  of Morone chrysops. The comparison of the amino acid sequence of signal peptide piscidin is quite similar to Dicentracin-like of that species registered in the genebank, and mature peptide piscidin sequence is similar in only three amino acids to Pleorocidin-like of Poesila farmosa and Dicentracin-like of Sphaeramia orbicularis. This study could be a step towards further studies of piscidin peptide.

Fish genome contains two copies of growth hormone (GH-1 and GH-2) as a result of duplication process during evolution. The aim of this study was to distinguish GH-1 from GH-2 genes in Rutilus kutum (Mahi Sefid) from the Caspian Sea using sequencing techniques and application of specific restriction enzymes for these loci. For this purpose, five fish were randomly selected and samples for DNA extraction were isolated from caudal fin clips. The DNA was extracted by salting-out method. Then, fragments of 333 and 410 bp from exon 4, intron 4 and exon 5 of GH-1 and GH-2 genes were amplified and, following purification, sequenced on the gel. GH-1 sequence of R. kutum was not different from that of common carp on the long allele showing 100% overlap with each other. On the short allele, however, they showed differences in GH-1 sequence of carp at four positions namely 89, 94, 105, and 164 bp with an overlap of 99%. The GH-1 overlapped with GH-2 sequences from both common carp and R. kutum as 99% and 86%, respectively. Comparison of the GH-1 and GH-2 sequences derived from R. kutum showed that they mainly differed in Intron 4. Other differences observed were mutations at one or more nucleotides. Despite the high similarity in the nucleotide sequences, the differences detected are applicable as specific genetic markers for the discrimination between GH-1 and GH-2. By identifying and sequencing GH-1 and GH-2 genes, the sequences obtained can be used to reconstruct the phylogenetic relations, study different allelic forms more precisely, and establish relationships between these loci with important economic traits in R. kutum from the Caspian Sea.