Rideout WM, Eggan K, Jaenisch R. 2001. Nuclear cloning and epigenetic reprogramming of the genome. Science (New York, N.Y.). 293(5532):1093-8. Pubmed: 11498580


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. Survival of cloned animals to birth and beyond, despite substantial transcriptional dysregulation, is consistent with mammalian development being rather tolerant to epigenetic abnormalities, with lethality resulting only beyond a threshold of faulty gene reprogramming encompassing multiple loci.

Related Faculty

Photo of Kevin Eggan

Kevin Eggan investigates the mechanisms that cause motor neuron degeneration in Amyotrophic Lateral Sclerosis (ALS), and seeks to translate new discoveries into new therapeutic options for patients.

Search Menu