Abstract Abstract: Mammalian somatic cloning got great progress in past few years, people have paid more attention to the researching and developing programs based on animal cloning platform. The article discussed some cloning problems about animals, which included synchronization of donor cells with recipient oocytes, abnormality and premature senescence of cloned animals, and disputed on somatic cell passages in vitro. Current progress of mammalian cloning was also introduced briefly. At last author's ideas on animal cloning were elucidated.
