DNA barcoding is no substitute for taxonomy (original) (raw)

Sir

DNA barcoding, formerly a way of identifying DNA within foodstuffs, is now being proposed as a way to catalogue life.

At the First International Barcoding Conference, held at the Natural History Museum in London in February 2005, heads of research institutes discussed plans to use museums, herbaria and other biodiversity institutes as national centres for DNA barcoding. Several small grants promoting it as an economical way of cataloguing life have been awarded, with a view to seeding bids for larger consortium grants.

Claims for its benefits are extravagant. The Consortium for the Barcode of Life has stated: “DNA barcoding will make a huge difference to our knowledge and understanding of the natural world.” But that's a slogan. What of the science behind these undertakings?

The purpose of barcoding is to find a unique piece of DNA (cytochrome c oxidase subunit 1, for example) for every described species, so future taxonomists can run large biotic surveys without the need to learn or use morphological keys. Barcoding is at best a technology that may be able to spot DNA diversity within physically indistinct species. But even at this level it remains a genetic key to identify known species, rather than replacing traditional taxonomic practice.

However, this quick, cheap technology is in competition with taxonomy for funding. What cash-strapped student will want to enter a field such as taxonomy that takes years to master and offers little or no job prospects? A budding barcoder — with no interest in biology, let alone taxonomy — can be trained in a fraction of that time, quickly disseminate their ‘research’ globally and look forward to a well-funded career.

DNA barcoding may seem progressive to those who use the word ‘dusty’ whenever the subject of taxonomy arises. But the work of taxonomists provides knowledge of the organism, not a few possibly unique nucleotides. In any case, every barcode must be linked with a known, described specimen stored somewhere.

Given its high-profile launch, barcoding will almost certainly result in a plethora of newly ‘flagged’ DNA species that will never be formally described. One estimate is that it will take some 250 years for taxonomy to catch up with barcoding. True to form, barcoding has supplied an answer: ‘DNA taxonomy’ — cataloguing barcodes and assigning each to an unnamed species.

Traditional taxonomy cannot keep up with this ‘diversity’. How long will it be until even the specimen is no longer necessary to ‘understand’ the organism?

DNA barcoding generates information, not knowledge. The vast number of barcodes will tell us what we know: life is complex. Museums that encourage DNA barcoding to compete for funding with taxonomy are misguided, as the practice is counterproductive to furthering our understanding of life.

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Authors and Affiliations

  1. Buffalo Museum of Science, 1020 Humboldt Parkway, Buffalo, 14211, New York, USA
    Malte C. Ebach
  2. The Nature Institute, 20 May Hill Road, Ghent, 12075, New York, USA
    Craig Holdrege

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  1. Malte C. Ebach
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  2. Craig Holdrege
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Ebach, M., Holdrege, C. DNA barcoding is no substitute for taxonomy.Nature 434, 697 (2005). https://doi.org/10.1038/434697b

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