**The Expanding Role of DNA Barcodes: Indispensable Tools for Ecology, Evolution, and Conservation**

**Morgan R. Gostel 1,2,\* and W. John Kress 2,3,4**

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	- The Arnold Arboretum, Harvard University, Boston, MA 02130, USA

**\***Correspondence: mgostel@brit.org; Tel.: +1-(817)-463-4199

**Abstract:** DNA barcoding has transformed the fields of ecology, evolution, and conservation by providing a rapid and effective tool for species identification. The growth of DNA barcodes as a resource for biologists has followed advances in computational and sequencing technology that have enabled high-throughput barcoding applications. The global DNA barcode database is expanding to represent the diversity of species on Earth thanks to efforts by international consortia and expanding biological collections. Today, DNA barcoding is instrumental in advancing our understanding of how species evolve, how they interact, and how we can slow down their extirpation and extinction. This review focuses on current applications of DNA barcode sequences to address fundamental lines of research, as well as new and expanding applications of which DNA barcoding will play a central role.

**Keywords:** high-throughput sequencing; species interactions; metabarcoding; symbioses
