Methylation in embryonic stem cells in vitro.

Stem cells raise the possibility of regenerating failing body parts with new tissue. Before stem cells can safely fulfill their promise, many technical problems, including understanding the stem cell phenotype, must be overcome. DNA methylation, which is responsible for gene silencing and is associated with chromatin remodeling, is an epigenetic system that determines the specific characteristic of a variety of cells, including stem cells. Each cell type has a unique DNA methylation profile produced by varied loci-specific methylation. Investigation of such DNA methylation profiles provides a way of identifying pluripotent stem cells. Further, it is likely that analysis of the epigenetic status of stem cells may provide novel information regarding "sternness" within these populations.