Project description:BackgroundSarotherodon galilaeus (Linné, 1758) is a member of the family Cichlidae, which is considered the most important aquaculture freshwater species endemic to Africa and the Middle East. The genetics and molecular biology of this species are rare. This requires more comprehensive mitochondrial genomes-based phylogenetics to enhance understanding of the relationship and delineate this species.Methods and resultsHere, we assembled the complete mitogenome of S. galilaeus using Illumina high-throughput sequencing technology. The mango tilapia mitogenome was 16,631 bp in length with an AT composition of 53.4% and 46.4% GC content. It encodes 37 genes comprising two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and 13 protein-coding genes (PCGs) as well as the D-loop known as the control region. The phylogenetic tree was conducted to provide a relationship within the haplotilapiine lineage based on the maximum likelihood method, and the newly sequenced S. galilaeus was clustered with other Sarotherodon species.ConclusionOur results provide a new perception of the genetic basis of S. galilaeus species for further research on systematics, evolution, population genetics, and molecular ecology.
Project description:Sarotherodon galilaeus (Linnaeus, 1758), a cichlid species that is naturally distributed in African and Eurasian waters, was introduced in many Asian countries for aquaculture. To date, rare genetic studies focused on this species have hindered our understanding of this species. Here, we reported the complete mitochondrial genome of S. galilaeus that was sequenced using next-generation sequencing technology. The resulting mitogenome of S. galilaeus was 16,630 in length and comprised 13 protein-coding genes (PCG), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA genes (rRNA), and one control region (D-loop). Phylogenetic analysis indicated that Oreochromini species contained two lineages (I and II) and S. galilaeus clustered with Oreochromis aureus rather than other Sarotherodon species.
Project description: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% between Sarotherodonmelanotheron and Coptodon zillii to 0.49% between Clarias gariepinus and C. zillii, indicating that S. melanotheron and C. zillii are closely related. Based on the data obtained, the utility of COI gene was confirmed in accurate identification of three fish species from Southwest Nigeria.
