DNA barcoding: A taxonomist's point of view

DNA barcoding is a taxonomic tool that uses a short fragment of mitochondrial DNA as a marker for a particular species. The usefulness of DNA barcoding is predicated on the presence of a “barcoding gap” in the proportion of genetic variation in a ~600 bp region of the Coenzyme C Oxidase I gene—that there is an order of magnitude difference in intra- versus interspecific genetic variation. Taxonomists and systematists have used molecular tools for decades, including short sequences of a multitude of genes. The DNA barcoding phenomenon is new in its usage across the Eukaryotes and for the well organized and well funded campaigns of the Consortium for the Barcode of Life. Barcoding has been demonstrated to be useful for identifying species, associating life stages and sexes with known species, identification of cryptic species, and other uses. Major criticisms of barcoding include that the “gap” is an artifact of incomplete taxon sampling which leads to false positives and false negatives in identification, that misidentified specimens often are attributed to barcodes without proper vouchers, and that taxonomists are being further marginalized just when we need them most. I will discuss barcoding issues from the point of view of a taxonomist, citing current problems, and discussing the need to collaborate with qualified taxonomists in order to have DNA barcoding fulfill its lofty claims.