DNA barcoding was invented by Paul Hebert of the University of Guelph, in Ontario, Canada, in 2003. His idea was to  　 a unique identification tag for each species based on a short stretch of DNA. Separating species would then be a simple task of sequencing this tiny bit of DNA. Dr. Hebert proposed part of a gene called cytochrome oxidase I ( COI) as suitable to the task. All animals have it. It seems to vary enough, but not too much, to act as a reliable marker, and it is easily  　 , because it is one of a handful of genes found outside the cell nucleus, in structures called mitochondria. The idea worked, and it has dramatically reduced the time ( to less than an hour) and expense (to less than $2) of using DNA to identify species. And thus, in July this year, Dr. Victor' s mystery goby became Coryphopterus Kuna. It was the first vertebrate to have its DNA barcode-a sequence of about 600 genetic 'letters' -included in its official description. Barcoding has taken off rapidly since Dr. Hebert invented it. When the idea was proposed, it was expected to be a  　 to taxonomists trying to name the world's millions of species. It has, however, proved to have a far wider range of uses than the merely academic-most promisingly in the realm of public health. One health-related project is the Mosquito Barcoding Initiative being run by Yvonne-Marie Linton of the Natural History Museum in London. This aims to barcode 80% of the world's mosquitoes within the next two years, to help control mosquito-borne diseases. Mosquitoes are  　 for half a billion malarial infections and 1m deaths every year. They also  　 devastating diseases such as yellow fever, West Nile fever, and dengue. However, efforts to control them are consistently  　 by the difficulty and expense of identifying mosquitoes—of, which there are at least 3,500 species, many of them hard to tell apart.