It was one of the very first motion pictures ever made: a galloping mare filmed in 1878 by the British photographer Eadweard Muybridge. More than a century later, that clip ... is now the first movie ever to be encoded in the DNA of a living cell, where it can be retrieved at will and multiplied indefinitely as the host divides and grows. The advance, reported on Wednesday in the journal Nature ... is the latest and perhaps most astonishing example of the genome's potential as a vast storage device. George Church, a geneticist at Harvard and one of the authors of the new study, recently encoded his own book, "Regenesis," into bacterial DNA and made 90 billion copies of it. With the new research, he and other scientists have begun to wonder if it may be possible one day to do something even stranger: to program bacteria to snuggle up to cells in the human body and to record what they are doing, in essence making a "movie" of each cell's life. When something goes wrong, when a person gets ill, doctors might extract the bacteria and play back the record. It would be, said Dr. Church, analogous to the black boxes carried by airplanes whose data is used in the event of a crash. In 1994, [mathematician Leonard Adleman] Adleman reported that he had stored data in DNA and used it as a computer to solve a math problem. He determined that DNA can store a million million times more data than a compact disc in the same space.