DNA barcoding markers: A comprehensive review and taxonomic classification across species

DNA barcoding has revolutionized species identification and biodiversity assessment by employing short, standardized genetic sequences as molecular markers. Since its inception by Hebert in 2003, it has become a cornerstone of taxonomy, ecology, conservation, agriculture, and medicine. This review traces the historical development of DNA barcoding, highlighting the strengths and limitations of widely used markers such as COI in animals, ITS in fungi, rbcL and matK in plants, and alternative loci in algae. The discussion emphasizes how barcoding enables accurate identification of cryptic taxa, supports food and forensic authentication, and strengthens biodiversity monitoring across ecosystems. Advancements in multi-locus strategies, genome-based markers, and DNA metabarcoding have enhanced resolution and scalability, while next-generation sequencing, environmental DNA, and nanotechnology promise to overcome persistent challenges of low variability, amplification barriers, and incomplete reference databases. Despite ongoing limitations, DNA barcoding continues to be an indispensable, cost-effective tool that bridges classical taxonomy with modern genomics. By integrating emerging technologies and fostering global collaboration, it holds immense potential for transforming biodiversity science and ensuring sustainable ecosystem management in the genomic era.