How do you generate a DNA barcode?

1. A specimen is collected. The specimen is labeled with the collection data (e.g. who collected the specimen, where, on what date, etc.). The collection data is also entered into a database, where it is associated not only with the specimen itself but also with the DNA extractions and sequences generated from that specimen. 

2. Tissue is removed from the specimen - a bit of muscle, a piece of leaf, a hair follicle, a grain of pollen, or any other part of the specimen that contains DNA. Once the tissue is removed, the remainder of the specimen (the "voucher") is deposited in a public collection such as a museum, botanical garden, or herbarium.

3. DNA is extracted from the tissue. There are a number of methods for extracting DNA but they all have the same purpose: cells in the tissue are lysed (i.e. broken open), lipids present in the cell membranes are removed, proteins that may be associated with DNA molecules (such as histones) are removed, and the DNA molecules themselves are precipitated and isolated. All DNA extractions are stored in appropriate long-term storage facilities. Extractions may be stored indefinitely in freezers at -80ºC or at room temperature if the DNA is dried.

4. A gene is amplified from the DNA extraction using a primer pair designed to target that particular gene. After the gene is amplified, the exact nucleotide composition of the sequence can be determined.

5. The resulting DNA sequences are then placed in a reference database where they can be used to identify other specimens. Such databases include BOLD, GenBank and GBIF.ch.