Somatic cell nuclear transfer (SCNT) has valuable application in the swine industry as well as bioscience research, but it has been circumscribed because of its inefficiency.Erroneous reprogramming is considered one of the most important reasons leading to the death of SCNT embryo.Studies have found that X-linked genes are remarkably down-regulated in mouse cloned embryo compared with in vitro fertilization (IVF) derived embryos.