RFLP-PCR Analysis of Growth Hormone and Myostatin Gene Polymorphism in Pangasius hypophthalmus and Clarias gariepinus: Implications for Growth Performance in Aquaculture

Abstract

Growth-related traits, such as body weight and length, are influenced by key genes, including the Growth Hormone (GH) gene, which promotes somatic growth, and the Myostatin (MSTN) gene, a negative regulator of muscle development. This study investigated the genetic polymorphisms of the Growth Hormone (GH) and Myostatin (MSTN) genes in two economically important aquaculture species, Pangasius hypophthalmus (striped catfish) and Clarias gariepinus (African catfish), using restriction fragment length polymorphism (RFLP) analysis combined with polymerase chain reaction (PCR). A total of 300 fish (150 per species) were sampled from commercial farms in Southwest Nigeria, and genomic DNA was extracted from fin tissue. PCR amplification of the GH and MSTN genes was followed by RFLP digestion using HaeIII and EcoRI enzymes, respectively. Genotypic and allelic frequencies were calculated, and growth performance (body weight and total length) was analyzed across genotypes. The results revealed distinct polymorphic patterns in both genes, with the heterozygous genotypes (GH: AB; MSTN: CD) being the most prevalent in both species. In P. hypophthalmus, the AB genotype for the GH gene occurred at a frequency of 50%, while in C. gariepinus, the AB genotype was observed at 40%. For the MSTN gene, the CD genotype was dominant in both species, with frequencies of 60% in P. hypophthalmus and 70% in C. gariepinus. Growth performance analysis demonstrated that heterozygous individuals (GH: AB; MSTN: CD) exhibited significantly higher mean body weight and total length compared to homozygous counterparts (P < 0.05). For example, P. hypophthalmus individuals with the AB genotype had a mean body weight of 335 ± 20 g and total length of 23.0 ± 1.8 cm, outperforming AA and BB genotypes. Similarly, C. gariepinus individuals with the CD genotype showed superior growth (425 ± 30 g, 27.0 ± 2.3 cm) compared to CC and DD genotypes. These findings highlight the potential of GH and MSTN polymorphisms as molecular markers for selective breeding programs. The observed heterozygote advantage suggests that maintaining genetic diversity in breeding populations may enhance growth efficiency and productivity in aquaculture.