Strands of synthetic DNA can be used as invisible tags to deter counterfeiting

As one of the building blocks of the human genome, DNA has become an important agent in medicine and forensic crime fighting. Now DNA may be used to tag merchandise with codes that counterfeiters cannot crack. A trace of synthetic human DNA embedded with a hidden code and then applied to a designer dress, a CD or a DVD, or mixed into brand-name perfume, for example, could be used to authenticate a product — and enable someone with the key to the code to detect counterfeits