Evaluation of genetic similarity and distance among seven Clariid fish populations in Kano Rivers, Nigeria

Abstract

A population can only acquire new gene either through the immigration of individuals from surrounding populations. One of the greatest  advantages of microsatellite marker is that DNA sequence information is needed to perform the assay. Thus, a study was carried out to evaluate genetic similarity and distance in strains of Clariid species (Clarias gariepinus and Heterobranchus longifilis). In achieving this, 25 blood samples were gotten from Clarias gariepinus and 10 from Heterobranchus longifilis for DNA extraction. DNA were extracted, amplified and scored using  seven microsatellite markers. The markers were Cga01, Cga02, Cga03, Cga05, Cga06, Cga09 and Cga10. The gel images were then subjected to  molecular analysis using Genealex software to determine their base pairs and evaluate their genetic variability. The populations examined were Clarias gariepinus of River Dudusingaya (CgD), Ghari (CgG), Thomas (CgT), Karaye (CgK), Bagwai (CgB); and Heterobranchus longifilis of River Bagwai (HlB) and Ghari (HlG). Among the populations sampled, the genetic similarity ranged from 0.018 for CgD and CgT populations to 0.079 for CgT and HlG populations. The genetic distance observed in the populations ranged from 0.112 for CgG and CgB populations to 0.998 for CgT and CgK populations. The Clariid species that were closer indicated that the river locations shared tributaries and the Clariid species exchanged genetic materials over a long period of time. On the other hand, those that were farther apart indicated that they shared little or no tributaries. It can be concluded that the studied populations were not genetically pure but heterogeneous with varying degrees of genetic similarity and distance therefore, there were no. exhibition of genetic uniqueness and the populations were not isolated.

Keywords: Genetic similarity, Genetic distance, Clariid populations