The Glow-In-The-Dark Kitty

Cat owners might find a glow-in-the-dark kitty to be fairly useful—you’ll never trip over the cat at night again—but the Mayo Clinic scientists who created this glowing cat had a bigger goal in mind: fighting AIDS.

The substance that makes the cat glow is a version of the green fluorescent protein that lights up the crystal jelly, a type of jellyfish that lives off the West Coast of the United States. Years ago scientists realized that the gene for GFP is a perfect marker when they insert another new gene into an organism. By inserting a version of GFP along with their gene of choice, they could easily see if they were successful because the organism would glow. Since the technique was first developed, researchers have made many glowing animals, including pigs, mice, dogs, even fish you can buy in the pet store.