Genetic Variation among Four Species of Tilapia and Their Hybrid in Egypt Using Random Amplified Polymorphic DNA (RAPD) Analysis

In this study, Random Amplified Polymorphic DNA technique (RAPD) was used to characterize four Tilapia species and the hybrid (O. niloticus, O. aureus, S. galilaeus, T. zillii and Hybrid (O. niloticus x O. aureus)). Three samples of each species were collected from River Nile. The DNA of fish samples were extracted using DNA extraction kit. RAPD analysis was carried out using eleven RAPD primers, while only eight primers were given detectable bands. A total of 186 scorable bands obtained by RAPD-PCR technique across four tilapia species and hybrid genomes with 166 polymorphic bands. The similarity indices were high among tilapia species, science it ranged from 0.920 between O. aureus and O. niloticus, to 0.907 between hybrid (O. niloticus x O. aureus) and S. galilaeus. Therefore the phylogenetic relationships among four tilapia species and the hybrid were clearly resolved in dendrograms. They clustered in five branches: the first one includes O. niloticus, the second branch includes O. aureus, the third branch includes S. galilaeus, the fourth branch includes hybrid (O. niloticus x O. aureus) and the fifth branch includes T. zillii. This study concluded that, the molecular patterns showed by RAPD bands, represent specific bands and apparently are suitable tool to distinguish among tilapia species and hybrid. The results clearly revealed that the four tilapia and hybrid are distinctive species.