A DNA barcode, or a short standardized sequence that enables researchers to distinguish among many species, works the same way as the 12-number UPC identifies brands of flour or sugar. To systematically sort through the various inhabitants of the natural world, though, Hebert introduced the idea of reading a 650-letter fragment from the front end of a gene encoding the enzyme cytochrome oxidase I, which is shared by virtually all higher organisms. A feather, a scale or a piece of skin can all provide the DNA necessary for an identification, and with it, valuable information about a species’ relative numbers in a given locale, its geographic origins and even its evolutionary age