Dieter Egli, PhD, a NYSCF Senior Research Fellow, is co-author on a paper published in the August 19th edition of Nature Genetics, a study conducted in collaboration with the research group of Alex Meissner, PhD, of Harvard University. They studied how the mouse egg erases methylation marks on DNA that are specific to specialized adult cells yet differ in comparison to embryonic stem cells. These methylation marks are thought to be a major barrier in the reprogramming of a specialized cell to a stem cell. Within twelve days after nuclear transfer, they found that regulatory regions of genes were demethylated while repetitive DNA sequences remained methylated. This finding suggests that the egg contains factors that mediate the rapid and specific demethylation of genes, which may be important for development. Thereby, this work elucidates the potential of oocytes to reprogram specialized cells into stem cells.