Phylogenetic relationship among blackwater fishes in North Selangor Peat Swamp Forest via 16S rRNA gene

Blackwater fish are native to Asian waters, the genetic diversity of which is unknown to the rest of the world. Despite the fact that their scientific names are generally the same, the taxonomy of many blackwater fishes remains a mystery due to differences in physical features depending on place of origin. The majority of species are difficult to recognize and discriminate against due to a lack of well-defined characteristics for each species, ambiguous taxonomic categorization, and poorly resolved taxonomy. The 16S rRNA gene was used as the molecular marker for species identification and phylogenetic relationships between Blackwater fish from the North Selangor Peat Swamp Forest (NSPSF) and several species from the NCBI database. A total of 115 blackwater fish samples were collected from the NSPF. Molecular Evolutionary Genetics Analysis X (MEGA-X) was used to check all samples for sequence discrepancies. The Neighbour-Joining (NJ) technique was used to calculate the tree's branch lengths using Tajima Nei model and Kimura 2-parameter model, followed by Maximum Parsimony (MP) method to determine character change using the tree length. The phylogenetic tree analysis using the NJ and MP methods reveals that the NSPSF blackwater fish species are similar to various blackwater fish in the NCBI database, with a genetic distance of 0.15% and 15%, respectively, indicating high variability. The base composition revealed that the 16S rRNA gene is a conserved region, with a value of 44.04%. Therefore, the study demonstrates that 16S rRNA gene is wellsuited for species identification research. The findings of this study can assist understandings on the genetic relationships of several blackwater fish species from North Selangor Peat Swamp Selangor and contribute to species conservation efforts.