DNA Barcoding 101


DNA Barcoding 101 includes the laboratory experiment prototol and supporting resources for using DNA barcoding to identify plants or animals – or products made from them. Step-by step instructions are provided as web pages and as a downloadable PDF file. 2- and 3-D animations illustrate polymerase chain reaction, DNA sequencing, and other techniques used in the experiment.

First, a sample of tissue is collected, preserving the specimen whenever possible and noting its geographical location and local environment. A small leaf disc, a whole insect, or sample of muscle are suitable sources. DNA is extracted from the tissue sample, and the barcode portion of the rbcL or COI gene is amplified by polymerase chain reaction (PCR). The amplified sequence (amplicon) is submitted for sequencing in one or both directions.

The sequencing results are then used to search a DNA database. A close match quickly identifies a species that is already represented in the database. However, some barcodes will be entirely new, and identification may rely on placing the unknown species in a phylogenetic tree with near relatives. Novel DNA barcodes can be submitted to the database at the Barcode of Life Data System (BOLD) (www.boldsystems.org/) at the University of Guelph.

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