How many species are left on Earth -- and how would you know if you've stumbled across a new one?
We now about 1.7 million of the estimated 10-30 million species on the planet. If we had a database of unique genomes of every one, such questions would be readily answered; such information may be years away at best. Nonetheless, various efforts are underway to get an accurate accounting of the life forms on our planet (see WorldChanging posts here, here and here). The most promising pathway appears to be the "DNA barcoding" project. DNA barcoding narrows the particular characteristics of each species to a few, easily-identified genetic markers, which can then be read in the field with a handheld device. We talked about the initiation of the Barcoding Life program a year ago -- and we're now starting to see the results.
The BBC reports on the proceedings of last week's International Conference on the Barcoding of Life, hosted by the UK's Natural History Museum. At the conference, three major new projects were announced:
The Barcoding Birds of the World initiative, organised by The Rockefeller University, University of Guelph and The Smithsonian Institution. Collecting the DNA barcodes of all the 10,000 known species of birds in the world will further our understanding of the nature and variety of species and help to monitor bird populations and study their behaviour. Fish-BOL, a network to assemble DNA barcodes for all fish. Fish are the most diverse group of vertebrates and are an important part of people’s diet across the globe. This project, co-ordinated by the University of Guelph and CSIRO Marine Science Division will collect 15,000 marine and 8,000 freshwater species over the next five years, a task requiring the analysis of some 500,000 fish specimens. The Consortium for the Barcode of Life will develop an open archive of standardized DNA sequences from specimens held in major collections. The Consortium is working with the National Centre for Biotechnology Information and GenBank to enable scientists to transform a collection of individual DNA sequences into a rich source of species information for identification and discovery.
These will build on the datasets already available at the Barcoding Life database. The Birds of North America database, for example, has 264 species from 438 specimens (such as the DNA barcode for the Ruby-throated Hummingbird and the barcode for the Peregrine Falcon). The current database holds at most a few thousand species -- much work remains to be done.
The Consortium for the Bar Code of Life site at the Smithsonian Institution and the Barcode of Life site at Rockefeller University have links to abundant information about how the barcoding process works. Barcoding Life, Illustrated (PDF) is friendly to non-specialists, while Identification of Birds Through DNA Barcodes at PLoS Biology explains how the North American Bird database works in more technical language.
DNA barcoding is not without controversy. Some taxonomists are concerned that the easy identification of species through genetic markers will lead to a decline in the field of taxonomy in general (there is already friction between traditional taxonomists, who identify species largely through physical and behavioral characteristics, and genetic taxonomists, who focus only on the DNA -- and who argue that the current "tree of life" is faulty). Some biologists are concerned that the genetic markers won't prove as unique as currently thought, leading to confusion between closely-related species. There's also a reasonable concern that the information gathered by those seeking to catalog all life may not be as open as it should be. With great profits to be had from medicines derived from plants and animals -- and with naturally-occurring DNA sequences patentable -- we need to make certain that efforts to identify every life form out there doesn't lead to a "land grab" mentality putting the planet's genetic heritage into the hands of a wealthy few.