Goodbye, Dolly. What killed Dolly? Premature aging related to her unusual origin as a clone? Or just one of those things? If you read this morning's Boston Globe and New York Times, you're still wondering.

According to the Globe piece -- which carries Anne Barnard's byline, but which included reporting by staff writer Gareth Cook as well as wire-service material -- cloning almost certainly had something to do with the famous sheep's death at the age of six, "well short of the normal 11- to 16-year sheep lifespan." The report notes that Dolly "grew obese, developed arthritis, and showed signs of premature aging" during her brief but celebrated life.

Yet the Times' Gina Kolata reports almost exactly the opposite, writing that sheep that are kept indoors, as Dolly was, may have about half the 11- to 12-year life expectancy of those allowed to roam in pastures; that her arthritis was not unusual for a sheep allowed to live past the typical nine-month slaughtering age; and that her obesity was well under control. Kolata writes:

Her illness and death, Dr. [Ian] Wilmut [one of the scientists who helped create Dolly] said, probably had nothing to do with the fact that she was a clone. "It could equally well have happened if she was not a clone," he said.

So which is it? This piece, by James Meek in the Guardian, strongly suggests that cloning did, indeed, cause Dolly to age prematurely, and that her true biological age might even have been 11 -- the six years since she had been born plus the six-year age of the cell from which she was cloned.

Needless to say, the full truth won't be known for some time to come.