DNA methylation, which refers to methyltransferases (MTases)-catalyzed covalent addition of a methyl group to adenine or cytosine residues in the specific DNA sequence, is one of the hottest research areas on epigenetic modification of genomic DNA. According to numerous studies, DNA methylation may cause the change of DNA structure, stability and interaction mode between DNA and protein, thus affecting gene expression, which may lead to many neurodegenerative diseases, immune system diseases and even cancer. Therefore, development of sensitive, selective, simple, and economical methods for DNA methylation determination is highly required. With increasing progress in the methylation studies, a series of detecting techniques has been developed to match various requirements of methylation studies. All of these study methods can be divided into four groups: genome-wide methylation extent analysis, gene-specific methylation analysis, methylation transferase activity analysis and new methylated sites screening. Among these methods, electrochemical techniques have been widely used for DNA methylation determination and MTases activity. Here we briefly review the detection of DNA methylation. Then more detail in the work on the electrochemical method are described, including direct electrochemical analysis methods, indirect electrochemical analysis methods, electrogenerated chemiluminescence methods and photoelectrochemical methods. In the end, the prospects of DNA methylation analysis are introduced.

Contents
1 Introduction
2 Analysis methods for DNA methylation
3 Electrochemical analysis methods for DNA methylation
3.1 Direct electrochemical analysis methods for DNA methylation
3.2 Indirect electrochemical analysis methods for DNA methylation
3.3 Electrogenerated chemiluminescence methods for analysis of DNA methylation
3.4 Photoelectrochemical methods for analysis of DNA methylation
4 Conclusion