A bewildering array of morphologic nuances are needed to identify species. DNA sequences, aka DNA barcodes, can also be identifiers, with the advantage that anyone with the right device can name a specimen without having to consult an expert or search through taxonomic keys which are generally indecipherable to the non-specialist. As DNA barcode identifications become more common, will this mean a loss of biologically important knowledge? To my reading, the answer is no, as the subtle differences in specialized structures used to identify organisms generally provide little insight into how organisms live and what they do. Thus it is exciting that standardized COI DNA barcodes are being incorporated into species descriptions as this will help democratize access to species names and the biological knowledge they represent.
A 2007 monograph describes 11 new dogfish species in the genus Squalus from the Indo-West Pacific using “a rapid taxonomic approach” incorporating digital images, morphometric measurements, and DNA barcodes. Even for something as recognizable as a shark, it would be difficult for most persons to apply the morphometric measurements (example shown at left) used to characterize these new species. DNA barcoding has the potential to expand the pool of persons able to name shark species, helping those trying to understand shark biology and those assigned to enforce regulations that protect shark species. Biologists might choose to adopt DNA barcoding as a routine identification tool, rather than measuring “labial furrow length” or “internarial space”, for example.
For many organisms, even those of economic importance, the number of persons who can apply the relevant morphologic tools is often very small, and the value of DNA barcoding as a widely-accessible tool potentially greater.
In Can Entomol 139:319 (2007) Jean-Francois Landry, Agriculture and Agri-Food, Canada, provides a taxonomic review of the leek moth genus Acrolepiopsis in North America which includes serious pests of onion and garlic crops.
The monograph includes detailed morphologic illustrations of male and female specimens, cocoons, pupae, and crop damage, and for the non-specialist, DNA barcodes of 30 individuals from 5 of the 6 species, and these are also publicly available on the BOLD website http://www.barcodinglife.org under “Published Projects” tab, including maps showing collection locations and photographs of the individual specimens.
As shown below in the dissections of male Acrolepiopsis genitalia, the morphologic illustrations can be beautiful, but the distinctive characters are not necessarily informative about the biology of the species.
This entry was posted on Sunday, June 24th, 2007 at 8:23 pm and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.