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

Abstract

A population can only acquire new genes 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 was 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 Genalex 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.