Molecular Characterization of Fish Species Using Mitochondrial DNA 12S rRNA.

This study was undertaken to study the capability of a set of new primers (unpublished) to amplify partial sequence of mitochondrial DNA (mtDNA) 12S rRNA gene of marine and freshwater fish species. The primers namely Forward: 5’ - CAA ACT GGG ATT AGA TAC CCC AC - 3’, and Reverse: 5’ - TAC RCT TAC CAT GTT ACG ACT T - 3’ were able to amplify the seventeen fish species chosen for this study. Pairwise comparison of the sequence data of the 17 fish species were undertaken to study the intra-species variations in the partial sequence of mtDNA 12S rRNA gene. The Thunnus tonggol and Scomberomorus commerson showed the highest similarity that is 89.37%. Diagramma pictum and Siganus canaliculatus showed the second highest similarity with 86.26%. The lowest similarity seen between Leptobarbus hoevenii and Nemipterus bathybius with 67.77%. A total of 1354 nucleotide positional polymorphisms were recorded. The transition (TC and AG) 628 out of 1354 and the number of transversion was 514. The lowest number of nucleotide polymorphism was observed in Siganus canaliculatus 8.3% and Nemipterus bathybius has showed the highest nucleotide polymorphism with 26.81%. An unrooted neighbor joining tree (NJ) was constructed to study their genetic relationship