Molecular Info®

Molecular Info® Copy Right © 2001 Institute of Molecular Development LLC

Nuclear Cloning and Epigenetic Reprogramming of the Genome William M. Rideout III, Kevin Eggan, Rudolf Jaenisch The Science, August 2001, 293: 1093 - 1098. Cloning of mammals by nuclear transfer (NT) results in gestational or neonatal failure with at most a few percent of manipulated embryos resulting in live births. Many of those that survive to term succumb to a variety of abnormalities that are likely due to inappropriate epigenetic reprogramming. Cloned embryos derived from donors, such as embryonic stem cells, that may require little or no reprogramming of early developmental genes develop substantially better beyond implantation than NT clones derived from somatic cells. Although recent experiments have demonstrated normal reprogramming of telomere length and X chromosome inactivation, epigenetic information established during gametogenesis, such as gametic imprints, cannot be restored after nuclear transfer.