20 Years After Dolly the Sheep, What Have We Learned About Cloning?

Today marks the 20th anniversary of the announcement of Dolly the sheep, the first mammal cloned from an adult cell.Researchers at the Roslin Institute in Scotland were finally able to produce Dolly — cloned from the udder cell of an adult sheep — after 276 attempts, according to the National Human Genome Research Institute (NHGRI)."For a developmental biologist, the ability to clone an advanced mammal was thought to be impossible," Lawrence Brody, director of the Division of Genomic