Real but modest gains from genetic barcoding

Costa and Carvalho make a compelling case for the practical utility of barcoding fish. Essentially the barcode, the precise sequence of a carefully chosen few hundred base pairs of a mitochondrial gene found in all eukaryotes, is intended as a defini taxonomic criterion that can be added to the existing description of a species, but that has the enormous advantage of being applicable to any part of the organism. No existing part of most taxonomic descriptions can be applied to a fish finger, remains of animals in a fish’s stomach or, probably, a detached shark’s fin. Since, as they explain, there are important practical contexts in which it is desirable to relate such objects to their species of origin, detecting fraudulent fishmongers or violations of fishery preservation law, for example, the potential benefits are clear. They might also, in imaginable future circumstances, come to be of considerable benefit in providing definitive classifications for field biologists without easy access to relevant kinds of taxonomic expertise. tive