Earlier today, I took a walk in the blustery winds of Washington DC with Drew Endy, a synthetic biologist from MIT. We had just been talking with Congressional staffers about the promise and perils of being able to manipulate life. There was too much to fit into the ninety minute session, and so our conversation spilled out on the street. And one of the things we talked about was the question of whether you can put your signature on a living thing. The question came up thanks to Craig Venter and his team, who announced last week that they had synthesized the entire genome of a microbe. The research was impressive, but the press coverage was a bit ridiculous, as I explained here. The notion that Craig Venter was playing God (he isn't) has proven to be journalistic catnip. In fact, the story refuses to die. In their paper, Venter and his colleagues mentioned they had added "watermarks" to the synthetic genome to distinguish it from the natural one they had copied. On Monday, Wired reported that they had gotten scientists to decipher the watermarks, which turned out to be the names of the scientists themselves. Their discovery was picked up in the days that followed by other outlets. Drew Endy thought this was just more non-story. For one thing, he pointed out that the names were no secret. The scientists published all the watermarks in a supplementary table. But it was a non-story in a deeper way, Endy said. Watermarks imply that these signatures were somehow permanent marks of their makers. But to Endy, a better term is graffiti. If Venter and his colleagues implanted their new genome in a cell and it actually came to life, mutations would eventually strike the watermarks, turning "Craig Venter" into gibberish. It occurred to me that something even more drastic might happen. The scientists had put their signatures in parts of the genome that don't encode for proteins. Specifically, they chose spots that are sometimes invaded by parasitic pieces of DNA called transposons. Since the microbes don't suffer when the transposons strike these spots, putting watermarks in them wouldn't cause any harm either. But that also means that if the genome were inserted into cells, transposons might well insert themselves right into those watermarks, splitting them into fragments. Transposons also have a knack for slicing out chunks of DNA, so they might erase the signatures altogether. If you're looking for literary immortality, you may not want to make DNA your paper and ink.