AP BIOLOGY

Detailed explanation-1: -A total of 581 healthy mice were made, all of which were fertile and lived a normal life span of about two years. The efficiency of making the cloned cells neither worsened nor improved over the generations. “This is a very important set of results, ” geneticist George Church of Harvard Medical School told LiveScience.

Detailed explanation-2: -A team in the laboratory of Atsuo Ogura at the National Institute of Infectious Diseases in Shinjuku, Tokyo, cloned 12 mice by removing nuclei from testis cells and inserting them into enucleated egg cells. They compared these mice to a genetically similar group created by natural mating.