Molecular Identification and Phylogenetic Relationships of Threadfin Breams (Family: Nemipteridae) Using mtDNA Marker

Cytochrome c oxidase-1 gene sequences of mitochondrial genome were analyzed for species identification and phylogenetic relationship among the commercially important Nemipterus species. Sequence analysis of COI gene clearly indicated that all the nine fish species fell into distinct clads, which are genetically distant from each other and exhibited identical phylogenetic reservation. All the COI gene sequences provide sufficient phylogenetic information and evolutionary relationship to distinguish the nine Nemipterus species unambiguously. As per the neighbour-joining (NJ) and maximum likelihood (ML) trees, all the nine species are genetically distant from each other and exhibited identical phylogenetic reservation. Based on the NJ and ML phylogenetic trees N. mesoprion, N. zysron, N. hexodon, N. nematophorus, N. virgatus and N. bipunctatus were closely related with high bootstrap value (97). The overall mean Kimura two parameter (K2P) distances between the nine species was 0.109. The intra species K2P distance was high in N. japonicus (0.069) followed by N. peronii (0.050) and N. mesoprion (0.002). This study proves the use of mtDNA COI gene sequence based approach is an alternative tool for identifying fish species at a faster pace.