Unveiling the Genetic Diversity in Clarias gariepinus (Burchell, 1822) Using Random Amplified Polymorphic DNA (RAPD) Fingerprinting Technique

Abstract

The utilization of molecular markers-assisted genetic diversity study is critical and imperative for a more robust selection and breeding programmes in aquaculture. Twenty C. gariepinus species were randomly selected, 5 each from four Rivers/locations-Okurikan (OKU), Lemna (LMN), UNICAL Fish Farm (UFF) and MCC cultured fish site, in Cross River State, Nigeria for genetic diversity study using RAPD technique. Genomic DNA extraction and purification from caudal fin tissue sample was performed using ZR Genomic DNA tissue extraction Kit, primed using OPA09, OPA11 and OPA13 RAPD primers and amplified using PCR. The amplified fragments were ran on gel electrophoresis and visualized under ethidium bromide dye. Thirty four bands were generated by the three RAPD primers from the four C. gariepinus populations of which 28 were polymorphic, accounting for 82.35%. Polymorphism revealed by each fish population ranged from 92.86-100% while, gene diversity estimates ranged from 0.246±0.16-0.385±0.09. Intra-population similarity index ranged from 42.49-78.4% while, the inter-population similarity index across all population combinations ranged from 52.32-71.69%. These result also revealed that as genetic distances increases, genetic identities narrows between the wild and the cultured species. UPGMA dendrogram generated two major clusters with C. gariepinus species from OKU, UFF and MCC in cluster-1 and C. gariepinus species from LMN in cluster-2. Implicitly though, our results suggest that there were several genetic diversity in the populations studied, especially between the cultured and the wild, which could encourage selection of C. gariepinus from OKU and LMN populations for the purpose of breeding and improvement.

Genetic Diversity in Cultured and Wild Population of Clarias gariepinus (Burchell, 1822) in Nigeria Using Random Amplified Polymorphic DNA (RAPD) and Microsatellite DNA

“…The Figures respectively recorded for these statistics in this study are: 60.8%, 1.215 ± 0.045, 1.083 ± 0.004, 0.141 ± 0.006, 0.071 ± 0.003 for the cultured population, and 47.9%, 0.958 ± 0.046, 1.076 ± 0.005, 0.120 ± 0.006, 0.063 ± 0.004 for the wild (Table 3). These Figures are lower than reported in similar studies [16,21,[23][24][25].…”

“…Popoola et al [16,[21][22][23] reported percentage polymorphic loci of 68.5, 100, 89.9 and 74.7 for cultured), and ~93% (and 100% for cultured) respectively, which are higher than the 47.9% and 60.8% observed in this study for the wild and cultured populations respectively. In this present study, the cultured population showed a higher level of inherent genetic diversity and allele richness than the wild as revealed by indicators such as the percentage of polymorphic loci (%P), Number of Alleles (Na), Number of effective alleles (Ne), Shannon Information index (I), and expected heterozygosity (Nei's gene diversity).…”

“…This lower genetic diversity in both cultured and wild compared to what was recorded in similar studies could be an outcome of several factors which include the types of RAPD primers employed [23] or it may indicate a loss or an on-going loss of variability in both the cultured and wild species which may need to be stemmed by conservation interventions [27].…”

Genetic characterization of farmed and wild populations of African catfish (Clarias gariepinus Burchell, 1822) using the random amplified polymorphic marker

“…The average number of total gene diversity among the populations (HT) recorded (0.452) in the farmed population was higher than the one (0.402) observed in the wild population. Closer to the present study, Ikpeme et al (2015) also found high gene diversity (0.385 and 0.365) in two fish farms of Clarias gariepinus in southwestern Nigeria. However, Popoola et al (2014) obtained a relatively lower (0.30) gene diversity in the cultured population of C. gariepinus.…”

“…Clarias gariepinus is the most important and suitable catfish species for tropical aquaculture in Africa (Barasa et al, 2017). The C. gariepinus production in Nigeria exceeded that of Nile tilapia (Oreochromis niloticus), due to its high fecundity and fast growth, which contributes for about 70-80% of the total freshwater fish production (Ikpeme et al, 2015). It is found all over the country because it is the major culturable fish species in Nigeria.…”