Nobel de Medicina
Mario Capecchi, winner of the Nobel Prize in Medicine, talks about his work during an interview Monday, Oct. 8, 2007, at his home in Salt Lake City. U.S. citizens Mario R. Capecchi and Oliver Smithies and Sir Martin J. Evans of Britain won the 2007 Nobel Prize in medicine on Monday for groundbreaking discoveries that led to a technique for manipulating mouse genes. (AP Photo/Douglas C. Pizac)