Determination of DNA barcodes of six commercial fish species in Iran

Understanding the genetic structure of economically significant species in the Persian Gulf is essential prior to implementing conservation and enhancement measures for their populations. This study involved the extraction of total DNA from at least five samples of the swimming fins of the species under investigation, following standard methodologies. Specifically, a segment of the mitochondrial DNA (mtDNA) known as cytochrome c oxidase subunit I (COI) was successfully amplified and sequenced for six species prevalent in the Persian Gulf, identified locally as Rashgo, Sobeity, Sangsar, Shoride, Mish, and Halvasefid, and scientifically as Eleutheronema tetradactylum, Sparidentex hasta, Pomadasys kaakan, Otolithes ruber, Protonibea diacanthus, and Pampus argenteus. The amplified sequences ranged from approximately 600 to 650 base pairs. Phylogenetic relationships among the studied species were analyzed using a Neighbor Joining tree based on cladistic and phenetic data, which facilitated the assessment of genetic relationships and distances among the species. The findings indicated that Otolithes ruber and Protonibea diacanthus clustered within the same clade as sister groups, exhibiting low genetic divergence compared to samples from Taiwan and Canada. Additionally, Sparidentex hasta and Pampus argenteus formed sister groups with Protonibea diacanthus in the first clade, drawing samples from China, America, Canada, and India. Notably, Protonibea diacanthus specimens from the western Persian Gulf displayed a 200% genetic divergence when compared to typical specimens from Hormozgan province, indicating distinct clades. Conversely, Pomadasys kaakan was situated in a separate branch with greater genetic divergence relative to the previously mentioned species and included samples from Saudi Arabia. Furthermore, Eleutheronema tetradactylum was identified as a distinct haplotype alongside samples from Malaysia, Indonesia, India, and Bangladesh within the first clade and exhibited sister group relationships with Pomadasys kaakan. A significant observation was the presence of Protonibea diacanthus Mangout in the Khuzestan region compared to common Protonibea diacanthus found in Hormozgan province. This suggests a potential dominance of the Mangout morphotype in the western Persian Gulf relative to its counterpart in the eastern region. Should this hypothesis be validated through further research, it may indicate that this morphotype represents a new endemic species or variant specific to the Persian Gulf region.