title: DNA barcoding ofClarias gariepinus,Coptodon zilliiandSarotherodon melanotheronfrom Southwestern Nigeria.
abstract: DNA barcoding has been adopted as a gold standard rapid, precise and unifying identification system for animal species and provides a database of genetic sequences that can be used as a tool for universal species identification. In this study, we employed mitochondrial genes 16S rRNA (16S) and cytochrome oxidase subunit I (COI) for the identification of some Nigerian freshwater catfish and Tilapia species. Approximately 655 bp were amplified from the 5' region of the mitochondrial cytochrome C oxidase subunit I (COI) gene whereas 570 bp were amplified for the 16S rRNA gene. Nucleotide divergences among sequences were estimated based on Kimura 2-parameter distances and the genetic relationships were assessed by constructing phylogenetic trees using the neighbour-joining (NJ) and maximum likelihood (ML) methods. Analyses of consensus barcode sequences for each species, and alignment of individual sequences from within a given species revealed highly consistent barcodes (99% similarity on average), which could be compared with deposited sequences in public databases. The nucleotide distance between species belonging to different genera based on COI ranged from 0.17% betweenSarotherodonmelanotheronandCoptodon zilliito 0.49% betweenClarias gariepinusandC. zillii, indicating thatS. melanotheronandC. zilliiare closely related. Based on the data obtained, the utility of COI gene was confirmed in accurate identification of three fish species from Southwest Nigeria.
authors.affiliation: Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria.
authors.forename: Mofolusho O
authors.initials: MO
authors.lastname: Falade
authors.affiliation: Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Opene
authors.affiliation: Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria; Department of Biological Science, Edo University, Iyamho, Edo State, Nigeria.
authors.forename: Otarigho
authors.initials: O
authors.lastname: Benson
keywords: 16S rRNA; COI gene; Clarias; DNA Barcode; Tilapia