Researchers claim it's the first example of seamless, repeat cloning using the Dolly method—known as “somatic cell nuclear transfer” (SCNT)—in which the nucleus from an adult source animal is transferred to an egg with its nucleus removed. Until recently, the process was fraught with failures and mutations. But the team led by Teruhiko Wakayama, whose results were published today in the journal Cell Stem Cell, was able to create 581 clones from the same original mouse.
Scientists, including Dolly’s creator, have long felt the process was still too unstable—and too wasteful of precious eggs, given the failure rate—to be used on humans any time soon. But perhaps it's not so far off, after all."