ＤＮＡ甲基化是唯一发生在哺乳动物细胞内ＤＮＡ合成后的修饰作用，是调节基因表达的机理之一。尽管ＤＮＡ在调节细胞功能中的作用尚处在研究之中，但已被证明，甲基化状态的变化与细胞分化、癌症及自身免疫等多种情况有关。本报告旨在复习目前所了解的ＤＮＡ甲基化的生物化学? DNA methylation is the only modification that occurs after DNA synthesis in mammalian cells and is one of the mechanisms that regulate gene expression. Although the role of DNA in the regulation of cell function is still under study, it has been shown that changes in methylation status are associated with a variety of conditions, such as cell differentiation, cancer and autoimmunity. The purpose of this report is to review what is currently known about DNA methylation biochemistry.