GENETIC VARIABILITY IN CULTURED AND WILD POPULATIONS OF Clarias gariepinus (Osteichthys: Clariidae) USING RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) MARKER

Abstract

Three wild populations of Clarias gariepinus from Esaodo (River Osun), Owena (River Owena), and Agbabu (River Oluwa), and three farmed populations, viz: Akure, Ilesa and Ado-Ekiti, in Southwest Nigeria, were analysed for their genetic differences using Random amplified polymorphic DNA (RAPD) analysis. Live specimens comprising 40 individuals (680 ± 3.28 g) from each location were collected and kept in six concrete tanks (2x1x1m). Altogether 435 reproducible bands were obtained from six populations for the nine RAPD primers used. The Analysis of Molecular Variance (AMOVA) indicated that the sampled populations are significantly different from each other, and that 99% of the total variation resided within the population. The percentage of genetic identity (GI) of RAPD-PCR profile among six populations ranged from 74.6% to 83.5%, while Genetic distance of the six populations based on RAPD-PCR profile ranged from 0.180 to 0.293. Estimates of genetic variation in wild and cultured populations of C. gariepinus were made, and total and mean number of segregating fragments were 71 (89.9%), 34.5 and 59 (74.7%), 35.4, respectively. Total gene diversity within wild and cultured populations (Ht) was 0.3419 and 0.3010, respectively. The study established that there is genetic variability in both wild and cultured C. gariepinus. RAPD showed that samples within the wild and cultured populations under study were closer to each other than between the two habitats. With reference to total gene diversity values and total number of segregating fragments, the wild population was considerably more diverse than the cultured population.

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

“…The implication is that the differential among the primers used could have arisen due to the nucleotide sequence differences since the quality of the DNA template sources were good. Saad et al (2009) and Popoola et al (2014) reported lower percentage polymorphic loci of 68.5 and 74.7%, respectively in cultured C. gariepinus species, which did not corroborate with our current report of 100% for the cultured C. gariepinus population. However, our report agrees with the observation of Agbebi et al (2013).…”

“…This was true for C. gariepinus from MCC and UFF (cultured) with 0.027 as the genetic distance and 0.974 as genetic identity. Popoola et al (2014) reported a high genetic identity between two cultured populations of C. gariepinus in the southwest, Nigeria.…”

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).…”

“…To effectively manage brood stocks for optimum productivity, it is important to compare the genetic composition of cultured with the wild population because significant loss of genetic variation, attributable to low effective number of parents, domestication selection or the mating design, among other factors, have been reported in hatcheries. Moreover, the feral introgression of the cultured into the wild as a result of escapee fishes has a great tendency of eroding the genetic diversity of the wild, especially if the genetic composition of the cultured population had not been properly managed [16].…”