Living reference work entry
An epigenetic modification of DNA is the addition of a methyl (CH3) group to position 5 of a cytosine residue. The majority of methylation events in humans occur on cytosines that are located next to a guanine (5′-CpG-3′ dinucleotides).
DNA methylation results from the addition of a methyl (CH3) group to position 5 of a cytosine (Fig. 1). The addition of a methyl group by DNA methyltransferases is an epigenetic modification to DNA that is maintained after cell division and does not change the DNA sequence. 5′-CpG-3′ dinucleotides are not uniformly distributed in the human genome. CpG islandsare short stretches of DNA, usually located in promoter regions of genes, with an unusually high GC content and a significantly higher frequency of 5′-CpG-3′ dinucleotides compared to the rest of the genome. It is well accepted that DNA methylation is involved in gene regulation. Inhibition of transcription factor binding by methylation of the target sequence was the...
KeywordsMethylation Pattern Imprint Gene Pericentromeric Heterochromatin Restriction Landmark Genome Scanning Underlying Regulatory Mechanism
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
© Springer-Verlag Berlin Heidelberg 2015