The findings provide important validation for the bar-coding concept. The technique was viewed with skepticism early on by ecologists and taxonomists who doubted that one small piece of DNA could be used to reliably identify species. But the researchers found that bar-coding results corresponded to the traditional species classifications about 95 percent of the time. “Analysis shows that in the vast majority of cases bar-coding worked,” says Jim Edwards, director of the Global Biodiversity Information Facility in Denmark, an organization that promotes global sharing of biodiversity data. “I don’t know why there is divergence at the species level on this one little piece of DNA, but it works.”
Scientists caution that the bar-coding technique cannot definitively identify new species; genetic results must be used alongside more traditional taxonomic methods. In the bird study, for example, it’s not yet clear what to conclude about the gulls that share a genetic bar code. “Some of them may be the same species, or they may be young species that haven’t yet had time to evolve differences in this small region,” says Stoeckle.
Universities, museums, and other organizations around the world have created an international consortium to further develop the technique. Projects in progress are cataloguing the biodiversity of birds, fish, ants, and fungi. Hebert and collaborators have catalogued about 25,000 species to date, at a rate of about 2,000 specimens a week. They aim to analyze 500,000 species by 2014. “The goal is to register effectively every organism humans are likely to encounter,” he says.
The technology could eventually be used to identify crop pests or invasive species, or to monitor trade in endangered species. A fast way to catalogue species diversity could also be useful for conservation efforts. Scientists are now cataloguing various species in areas of Madagascar and the Amazonian rain forest, two areas undergoing rapid development. “Immense blocks of territory are under threat of development,” says Hebert. “They want to set aside regions of highest unique biodiversity, and we come in with a fast survey tool.”