DNA Barcoding, primarily focusing on cytochrome coxidase subunit I (COI) gene has been appraised as an effective tool for species identification. Nonetheless, species identification based on molecular approach is essential for discrimination of look-alike species. In this study, we focused on the marine fishes Family Nemipteridae, one of the commercially important group distributed within the surrounding seas of Malaysia. Some of the samples were collected during the National Demersal Trawl Survey in the Exclusive Economic Zone of East Coast Peninsular Malaysia by the Department of Fishery Malaysia. A 652bp region of COI was sequenced for 74 individuals from nine putative species. Additional 34 COIsequences from GenBank were also included in this study making the total number of samples analysed to 108 individuals. The averageKimura 2-parameter (K2P) nucleotide divergence was 0.34% among individuals within species and 6.97% within genera. All putative species formed monophyletic clades in both Neighbour-joining (NJ) and Maximum-likelihood (ML) trees. However, there was a potential misidentification in specimen identified as Nemipterus tambuloides,as the specimen did not group with their own taxa. It was genetically grouped in Nemipterus thosaporni clade. This study supports the effectiveness of COIgene in species discrimination of Family Nemipteridae.
Present study investigates the genetic diversity and genetic distribution of the longtail tuna Thunnus tonggol collected from east Malaysia (Borneo states of Sabah and Sarawak) based on mitochondrial DNA D-loop sequence analysis. 58 fish samples were obtained, specifically from Kota Kinabalu, KK (n = 22), Miri, MR (n=20) and Bintulu, BT (n = 17). DNA template was isolated using the salt extraction method. Final length of 404 base pair (bp) D-loop sequences revealed 52 haplotypes that comprise of 77 variable sites (38 of parsimony informative and 39 singleton). A total of 20 haplotypes were found in KK, 19 haplotypes in MR and 16 haplotypes in BT. Molecular diversity indices revealed high haplotype diversity and low nucleotide diversity in all populations; KK (h = 0.9913 ± 0.0165, π = 0.00239 ± 0.0127), MR (h = 0.9942 ± 0.0193, π = 0.0226 ± 0.0121) and BT (h = 0.9926 ± 0.0230, π = 0.0196 ± 0.0171). Population comparison pairwise FST show that KK and BT were significantly genetically differentiated. The result from this study will be beneficial for fisheries management and also to provide information on the population genetics of T. tonggol in East Malaysian waters.