author(s)
Md. Faruque Miah, Toufiqur Rahman, Shahena Aktar Shipa and Anindita Chakrabarty

abstract
Genetic diversity of any fish is most important for their existing, breeding, production and management. In this study, intra-species genetic variation of a wild population of walking catfish, Clarias batrachus in Sylhet, Bangladesh was investigated. Four RAPD markers such as OPB-19, OPB-12, OPB-05 and OPF-14 were used to assess genetic variability among 8 individuals of C. batrachus genotypes. Less number of DNA bands was revealed by all the primers in experimental populations where a total of 132 bands were detected and all the markers were shown different levels of polymorphism. Intra-specific polymorphisms were recorded 60%, 55.56%, 40.91% and 30.77% in primer OPB-12, OPB-19, OPF-14 and OPB-05 respectively where average polymorphism was recorded 46.81%. Average gene diversity was found 0.19823. The genetic distance of experimental samples ranged from 0.6 to 1 and in an average 0.88, indicating higher genetic distances of this population. A genetic relationship among the individuals of the experimental population was constructed where 3 clades and 2 sub-clusters were recorded considering different linkage distances. Considering different genetic parameters genetic variability was found higher among this experimental population.