Although the public's imagination has been taken by the possibility of taking any cell from an adult mammal and turning it into a clone, it may not be true that just any cell will be amenable to the technology applied by the researchers at PPL Therapeutics and the Roslin Institute.

The mammary tissue from which a lamb was cloned is different than many other types of tissues in the body, in that it may contain a higher proportion of cells that are not terminally differentiated