Molecular Identification and Phylogenetic Analysis of <i>Hydra vulgaris</i> from Greater Zab River, Iraq

No genomic data for Hydra vulgaris was recorded in Iraq. DNA barcoding is a modern technique used for accurate identification that is more important than previous studies utilizing morphology characters. This study aims to investigate the identification of H. vulgaris based on genomic analysis using the mitochondrial gene Cytochrome Oxidase I (COI) and construct a phylogenetic tree as the first study in Iraq. In our current investigation, we found species of Hydra from the Greater Zab River during June–July 2022, with average Water temperatures (25.1–29.6°C), Hydrogen potential (pH) 7.5–7.8, and Dissolved Oxygen (DO) 6.3–7 mg/l. As a result, the acquired sequencing data for H. vulgaris was registered in the GenBank database (OP521891.1) for the first time. There were minimal genetic differences across the same strains (zero – 0.09); however, there was maximum divergence (0.424–0.508) to other species due to geographic distribution. Also, applying phylogenetic methods such as Maximum Likelihood, Maximum Parsimony, and Neighbor-Joining, it was verified that the Hydra species belongs to the ‘vulgaris’ group. According to aquatic parameters, only water temperature shows no significant correlation according to months (P < 0.05). In contrast, pH and Dissolved oxygen show significant (P > 0.05) differences according to period studies and are correlated with species. Finally, it should be noted that this particular strain is used as a bioindicator for ecology, adapted to environmental assessment and geographical location.