Scientists say they have bred a dog that glows under ultraviolet light when an antibiotic is added to its food. Scientists started cloning glow-in-the-dark puppies two years ago by inserting genes from other species that produce fluorescent proteins, such as jellyfish and coral. In the journal Genesis, researchers from Seoul National University report that they produced a dog that expresses the green fluorescent protein gene when it eats food containing a doxycycline antibiotic. When the drug is no longer added to the food, the glow-in-the-dark effect fades away. The technique could be used to help find cures for human diseases such as Alzheimer's and Parkinson's, South Korea's Yonhap news agency reported. The genetically modified female beagle, named Tegon, was born in 2009. Other methods can produce dogs that glow, but the uncontrollable expression often results in unwanted outcomes," they said.