DNA barcodes for ecology, evolution, and conservation

•DNA barcodes are becoming an integral tool for the identification of species and the understanding of the evolution and ecology of biodiversity.•Although the specification of a single short DNA region as a universal identifier for all of biodiversity has not materialized, a few genetic markers have now been identified to assist in the DNA barcode endeavor.•DNA barcodes are providing resolved local phylogenies of plant taxa to aid understanding of the principles of how species are assembled into communities and the evolution of functional traits in these assemblages.•Previous attempts to resolve multispecies interactions have been enhanced through use of DNA barcodes in investigations of trophic interactions and ecological forensics. The use of DNA barcodes, which are short gene sequences taken from a standardized portion of the genome and used to identify species, is entering a new phase of application as more and more investigations employ these genetic markers to address questions relating to the ecology and evolution of natural systems. The suite of DNA barcode markers now applied to specific taxonomic groups of organisms are proving invaluable for understanding species boundaries, community ecology, functional trait evolution, trophic interactions, and the conservation of biodiversity. The application of next-generation sequencing (NGS) technology will greatly expand the versatility of DNA barcodes across the Tree of Life, habitats, and geographies as new methodologies are explored and developed.