Interest in the potato genome is primarily agricultural; scientists hope that with the help of the draft genome unveiled last year, they can breed potatoes that are, for instance, drought-tolerant or more nutritious. But there's basic plant biology to be learned, too. The potato and the tomato only diverged 10 million years ago--a blink of the eye in evolutionary time--and yet they are vastly different. "One is a fruit that grows on a vine and the other is this weird tuber that grows underground," says C. Robin Buell, a plant biologist at Michigan State University. "What makes a potato a potato?" With the help of the draft genome, Buell is working to find out.