Edward M. Marcotte is looking for drugs that can kill tumors by stopping blood vessel growth, and he and his colleagues at the University of Texas at Austin recently found some good targets — five human genes that are essential for that growth. Now they’re hunting for drugs that can stop those genes from working. Strangely, though, Dr. Marcotte did not discover the new genes in the human genome, nor in lab mice or even fruit flies. He and his colleagues found the genes in yeast. “On the face of it, it’s just crazy,” Dr. Marcotte said. After all, these...