Molecular Validation of Cichlids from Zobe Reservoir, Dutsin-Ma, Katsina State, Nigeria Using Cytochrome Oxidase (COI) Genes

The species of cichlids are easily misidentified due to their morphological similarities. This study, therefore, was designed to discriminate the cichlid species inhabiting Zobe reservoir using a molecular approach. Samples of different cichlid species were collected from the reservoir between August and November 2022 and identified using their morphological features following the field guide to Nigerian freshwater fish. Fin clips of two samples from each of the species were fixed in 100% ethanol and the DNA was extracted. The mitochondrial cytochrome oxidase (CO1) gene area was amplified (using the FishF1 and FishR1 primer pair), purified and sequenced to reveal the identity of the species. Morphologically, the result revealed the presence of four species, namely: Oreochromis niloticus, Oreochromis mossambicus, Sarotherodon galilaeus, and Coptodon zilli. The genetic identity of the samples agreed with the earlier attempt made at morphological discrimination except for O. mossambicus which matches the partial and complete genome of Oreochromis aureus, hence, solving misidentification. The phylogenetic tree of the CO1 genes constructed using MEGA 11 software reveals the species were grouped independently into the three different genera of the Cichlidae family (i.e., the Coptodon, Oreochromis and Sarotherodon). This study affirms the need for molecular confirmation of morphologically identified cichlids in Nigeria. Keywords: Cichlids, DNA Barcoding, Identification, Phylogeny, Polymerase Chain Reaction