First record of COI Gene-Based DNA Barcoding of Terapon jarbua and Terapon puta in Pakistan

The Terapontidae fish family is an important coastal fish assemblage in Pakistan that contributes to local fisheries. Despite its economic and ecological importance, no previous genetic studies of terapontid species have been reported from Pakistani waters. DNA barcoding, particularly using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences, is a relatively novel method for species identification. COI gene sequences can be effectively used to confirm species identity and investigate phylogenetic relationships among species. The aim of this study was to generate mitochondrial COI gene-based DNA barcodes for Terapon jarbua and Terapon puta fishes collected from Pakistan. DNA was extracted using the CTAB method, and PCR reactions were carried out using Fish F1/R1 and F2/R2 primer pairs. A total of 13 sequences of Terapontidae family (Terapon jarbua, Terapon theraps, Terapon puta, Pelates quadrilineatus) were downloaded from NCBI database and aligned with the sequences generated in this study using multiple sequence alignment tools. The interspecific divergence and intraspecific variation were estimated using the Kimura 2-parameter model in MEGA X, while phylogenetic relationships were reconstructed using the Maximum Likelihood method. Intra-specific divergence was very low (0.007) compared with the inter-species divergence (0.687). Phylogenetic analysis indicated a close evolutionary relationship between T. jarbua and P. quadrilineatus, while T. puta showed a distant relationship. This study provides the first DNA barcodes for T. jarbua and T. puta (Family: Terapontidae) from Pakistani waters. The use of DNA barcodes is discussed as an essential tool for identification of existing species within Terapontidae fish family and for investigating their evolutionary relationships. In future, these DNA barcodes will help detect cryptic species and contribute to the study of new species within the family. Precise species identification is an essential first step toward the future conservation and management of fishery resources in Pakistani waters.