DNA Methylation (image) NIH/National Eye Institute Share Print E-Mail Caption DNA methylation is an epigenetic mechanism essential for normal cell development and differentiation, and is also associated with aging and the formation of cancers. When present, DNA methylation generally represses gene expression. Credit NIH Common Fund, adapted from Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.