According to two recent studies, a DNA barcode could revolutionize taxonomy, potentially saving hours of peering down microscopes or poring over lists of morphological features to identify species.

The barcode in question is a 648-bp stretch of the mitochondrial gene cytochrome c oxidase-I. As mitochondrial genes mutate at a high rate, enough changes should have taken place in this gene to provide a unique sequence for each species, allowing taxonomists to quickly and accurately identify specimens.

A group led by Paul Hebert at the University of Guelph tested the technique in a study of 260 bird species. The barcoding approach proved an accurate way of distinguishing between species, and even identified four potential new species that might have been missed previously. “[Birds are] big, they're coloured differently, and they sing different songs ... yet even in that easy to identify group, there are hidden species,” commented Hebert (CBC News Online).

In a second study, the same technique revealed that the skipper butterfly, Astrapes fulgerator, is actually made up of at least ten species that look similar as adults, but have different characteristics as caterpillars. Taxonomist Felix Sperling, who wasn't involved in the study, is enthusiastic, describing this work as “an excellent demonstration of the power of DNA barcoding to make sense of a confusing welter of ecological and color pattern variation” (The Scientist Online).

But the method is less popular among some taxonomists, and even those who are in favour are far from suggesting that barcoding is the solution to all taxonomic problems. “There's strong debate about whether one size fits all,” stresses ecologist Craig Moritz, “We have to be a little bit cynical about where it works and where it doesn't” (news@nature.com ).