DNAmethylaatio

DNA methylation is a biochemical process that involves the addition of a methyl group (CH3) to the 5' carbon of a cytosine nucleotide within a DNA molecule. This modification typically occurs on the cytosine residue of a CpG dinucleotide, where cytosine is followed by guanine. DNA methylation plays a crucial role in various biological processes, including gene regulation, X chromosome inactivation, and genomic imprinting. It is a heritable epigenetic modification that can influence gene expression without altering the underlying DNA sequence. DNA methylation patterns are dynamic and can change throughout an organism's lifetime in response to environmental factors and developmental cues. Abnormal DNA methylation has been linked to several diseases, such as cancer, neurological disorders, and developmental abnormalities. The process is catalyzed by DNA methyltransferases, which transfer the methyl group from S-adenosylmethionine to the cytosine residue. Conversely, DNA demethylation is mediated by enzymes like ten-eleven translocation (TET) proteins and DNA glycosylases. Understanding DNA methylation is essential for comprehending its role in health and disease, as well as for developing targeted therapies.