Dna and Edna-Based Techniques for Characterizing Three Unionid Bivalve Species in the Northern River Nile, Egypt

Bivalve mollusks are avid filter feeders. They filter significant amounts of algae, bacteria, sediment, nutrients, and other particles from the waters, playing a key benthopelagic regulatory role on the freshwater ecosystems. To provide DNA-based approach and environmental DNA (eDNA) based-techniques for accurate species identification and tracking, three different unionid bivalves were collected from North of the River Nile, belonging to the genera Coelatura, Mutela, and Chambardia. They were subjected to DNA barcoding, through sequencing the hypervariable barcode region of the mitochondrial cytochrome oxidase subunit I gene (COI), and phylogenetically analyzed. Also, the resulting barcodes were used to design species-specific PCR assays that were tested over waters where the three species were co-incubated. The results revealed that the collected species were mainly Mutela rostrata and Chambardia rubens. The third species showed barcoding and phylogenetic proximity to Coelatura aegyptiaca, yet mixed identity was found with two other Northeastern African Coelatura species. eDNA-based PCRs provided specific, clear amplicons for the three species. Based on these results, it is strongly recommended to extend the application for molecular techniques for further investigation of hidden diversity in the world of River Nile bivalves in Egypt to detect their exact species, abundance, and status of conservation.