DNA Sequence Characteristics and Phylogenetics of Three Oligonucleotides Markers on Clariid Species

Aims: The aim of this study is to express the profiles of three oligonucleotide markers corresponded to reproductive genes that may be different between the two Clariid species (Clarias gariepinus and Heterobranchus bidorsalis) and their phylogenetics.

Methodology: Total DNA isolation was carried out on the whole blood of the two strains of Clariid species – 100 species Clarias gariepinus male and female (1.2 – 1.5 kg, 34 – 52 cm) separately; 100 species Heterobranchus bidorsalis (1.7 – 2.2 kg, 38 – 60 cm) respectively using the Quick-gDNA Zymo research kit. Having ascertained the DNA stability on 0.8% agarose gel, NCBI database and Clustal analyses were employed to design primers to reproductive genes that may be different between the two catfishes and may participate in their differential reproducibility. We have used quantitative real-time PCR to investigate the expression of three selected oligonucleotides markers on the catfish. CLC Sequence viewer 7 software was used to analyze the nucleotide alignment percentage and develop the phylogenetics tree.

Place and Duration of Study: The study was carried out in the Biotechnology Centre, Federal University of Agriculture, Abeokuta Nigeria between January and July 2014.

Results: We observed a dimorphic expression pattern of the three marker genes in relation to strains and sex differentiation, indicating that sox9a retained its function in testis, Figα was highly expressed in the female and Cyp19a1b was up-regulated in male C. gariepinus than male H. bidorsalis catfish species. The phylogenetic tree showed that male Heterobranchus and female Clarias were closer irrespective of male or female while male Clarias differed from the two.

Conclusion: To date, these three genes, Sox 9a, Figα and Cyp19a1b have been detected in many fishes, but little or no data has been reported in African catfishes. The findings from this study might be used as the target gene for catfish gender regulation.