Progress on somatic cell nuclear transfer

Somatic cell nuclear transfer offers exciting opportunities in many areas and brings tremendous changes to agriculture, conservation and therapeutics. However, the fundamental research of nuclear transfer including nuclear reprogramming is not fully understood. Some inappropriate epigenetic modifications have been reported in the clone animals, including abnormal regulation of DNA methyltransferase expression, improper expression of imprinted genes,reactivation of the inactive X chromosome. The low efficiency of nuclear transfer hinders the further progress in some degree, we describe some recent advances in applications, methods and main problems limiting efficiency.