DNAmetyyliryhmät

DNAmetyyliryhmät refers to the addition of a methyl group (CH3) to a DNA molecule, a process known as DNA methylation. This epigenetic modification is crucial for regulating gene expression without altering the underlying DNA sequence. In mammals, DNA methylation primarily occurs at cytosine bases, specifically when a cytosine is followed by a guanine, forming a CpG dinucleotide. These CpG sites are often clustered in regions called CpG islands, which are frequently found in the promoter regions of genes.

The presence of DNA methylation in a promoter region typically leads to gene silencing. The methyl groups can physically hinder the binding of transcription factors to the DNA, or they can recruit proteins that condense the chromatin structure, making the DNA less accessible for transcription. Conversely, demethylation, the removal of methyl groups, is generally associated with gene activation.

DNA methylation plays vital roles in numerous biological processes, including embryonic development, X-chromosome inactivation, genomic imprinting, and the suppression of transposable elements. Aberrant DNA methylation patterns are implicated in various diseases, most notably cancer, where both hypermethylation and hypomethylation of specific genes can contribute to tumor initiation and progression. Understanding DNAmetyyliryhmät is therefore central to comprehending gene regulation and disease mechanisms.