The conservation for biodiversity in Iraqi freshwater environments is important to protecting native species from the environmental impacts of alien species. Clarias gariepinus (Burchell, 1822) (Siluriformes, Clariidae) has been recognized as an alien species in Iraqi water bodies. This study aims to use molecular DNA to identify this catfish and trace its origins using. The DNA sequences of C. gariepinus were done using the mitochondrial DNA cytochrome c oxidase subunit 1 (COI) gene, and a specific primer set. The polymerase chain reaction (PCR) amplification was used to align the COI gene as a barcoding marker. After analysis, the sequences were compared with sequences in the National Center for Biology Information (NCBI) database using BLAST. Molecular analysis and genetic sequence reconstruction revealed that the COI gene is instrumental in the genetic identification of C. gariepinus. The phylogenetic tree indicated a close genetic link between the Iraqi samples and populations from China and North Korea, suggesting that these may represent the closest known lineages to the origin of this species in Iraq. The findings showed that the selected COI gene is a reliable indicator for tracking the origin of alien catfish populations in the Iraqi environment. This study contributes to the development of molecular detection of alien species in Iraq. The accession numbers LC868421 and LC868422 were employed to submit the sequences to the NCBI GenBank database.
