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What is DNA barcoding?

DNA barcoding is a method that uses a short fragment of an organism’s DNA (the “barcode”) to identify it as belonging to a particular species. This fragment is ideally conserved within species but variable among species, so that a genetic barcode sequence serves as a unique identifier for a single species. In this sense, DNA barcodes serve a similar function to the numeric barcodes found on products in the supermarket: to act as distinct identifiers for individual products.

The use of DNA barcoding for species identification is dependent upon a DNA reference library, which is a database containing DNA sequences generated from identified specimens. The barcode sequence of an unidentified specimen may then be compared to sequences present in the reference library in order to determine the identity of the specimen. The DNA barcoding method of species identification is inexpensive, fast and reliable, making it an ideal complement to morphology-based taxonomy.
 
Our goal is to create a DNA reference library for all species in Switzerland. The success of a DNA reference library as a tool for species identification is dependent upon correctly identified voucher material, highlighting the importance of an ongoing collaboration between SwissBOL and taxonomic experts. DNA barcoding may also reveal new or cryptic species that will require formal description by taxonomists, furthering the need for taxonomic support.
       
While barcoding using Sanger sequencing typically amplifies gene regions for single specimens, next-generation sequencing technology allows for the amplification of gene regions from samples consisting of many specimens. This so-called “environmental barcoding” may be employed to analyze the species composition of samples of soil or water and is thus valuable as a tool in biomonitoring programs.