What is DNA Barcoding?
In 2003, researchers at the University of Guelph in Ontario, Canada, proposed “DNA barcoding” as a way to identify species using a short, standardized fragment of their DNA. Plant pests are typically identified by professional taxonomists using morphological “keys”. If a specimen is damaged or is in an immature stage of development, even specialists may be unable to make identifications. Barcoding solves these problems, because barcodes can be obtained from tiny amounts of tissue allowing anyone to make a quick identification.
The gene region that is being used as the standard barcode for almost all animal groups is a 648 base-pair region of the mitochondrial cytochrome c oxidase subunit 1 gene (“COI”). By first creating a reference database of DNA barcodes derived from known species identified by expert taxonomists, barcodes can be generated from unidentified specimens and queued against the reference database and when a match is found in the reference database the taxonomic identify of the unidentified specimen can be inferred.
DNA barcoding is ideally suited for bio-monitoring applications such as pest monitoring, and differs in three important ways from traditional morphological approaches to species identification.
- DNA barcoding extends existing taxonomic knowledge, by allowing non-experts to identify species using DNA barcode reference libraries.
- Many steps of the DNA barcoding workflow can be automated greatly increasing the number of specimens which can be identified in a given time.
- DNA barcoding is capable of identifying any life-stage of an organism (e.g. eggs, larval, juveniles), or physically damaged specimens.
The primary reference library for DNA barcodes is the Barcode of Life Data Systems (BOLD); which provides an integrated environment for the assembly and application of DNA barcodes. In addition to being a reference library for DNA barcodes, BOLD also provides an annotation framework that supports tagging and commenting on records and their components (i.e. taxonomy, images, and sequences), allowing for community-based validation of barcode data. Statistics presented on Plant Pest Barcoding are derived solely from DNA barcode data present in BOLD.
For general information on DNA barcoding refer to:
- Stoeckle, M. Y. & Hebert, P. D. N. (2008) Barcode of life. Scientific American, 299.
- Jinbo, U., Kato, T. & Ito, M. (2011) Current progress in DNA barcoding and future implications for entomology. Entomological Science, 1-18.
- Canadian Centre for DNA Barcoding
- International Barcode of Life