DNA barcoding is based on a gamble (or maybe a shrewd guess), and perhaps a smidgin of circular thinking: that there is a chunk of genome short enough to sequence quickly and cheaply, and which shows just enough variability for the entire sequence to be the same for all members of a species, but different for different species. Well, the gamble seems to have paid off. A suitable bit of a gene has duly been identified for both animals and plants, data are being ammassed, and there’s talk of a portable gadget being available in a few years which will read off the relevant sequence from a bit of leaf or skin or something and compare it with a database to give you the species name right there in the field.
The DNA barcoding fraternity met recently in Taipei for the 2nd International Barcode of Life Conference to gauge their progress since their first meeting two years ago:
In 2005, there were 33,000 records covering 12,700 species in the Barcode of Life Data Systems (BOLD) at the University of Guelph, Canada. Today over 290,000 records have been banked, representing over 31,000 species, and data accumulate at an accelerating pace (see www.barcodinglife.org/views/taxbrowser_root.php).
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Barcodes are in hand for about 20% of the world’s estimated 10,000 bird species, and about 10% of the estimated 35,000 marine and freshwater fishes. An emerging international research network plans barcode coverage of more than 500,000 species of all kinds within five years.
Technologies and processes available today can identify a species through its DNA within a few hours at a cost of less than US $2. Scientists believe that process will soon be shaved to mere minutes and a few pennies using new, highly-portable technologies such as DNA microchips, massively parallel sequencers and microfluidic systems.
Two North American “barcode factories” (at the Smithsonian Institution, Washington D.C., USA, and the University of Guelph, Canada) are now able to produce hundreds of thousands of barcodes per year. Meanwhile, a new network of 17 “Leading Labs” has been created to share and disseminate barcoding information and offer training.
The EurekAlert article from which the above quote is taken also gives a number of interesting examples of the application of the technology to specific problems. For example, researchers have “DNA barcoded all 689 species listed in World Economic Plants: A Standard Reference, a prelude to testing the identity and purity of plant-based medicines and herbals.” I’d really like to see the method used on a large, complicated genus of wild crops relatives, like Vigna or Aegilops. Maybe someone’s already working on it.