A CpG dinucleotide is a sequence of two DNA nucleotides, cytosine (C) followed by guanine (G), that are adjacent to each other on the same DNA strand. This sequence is also known as a CpG site or CpG island.
CpG dinucleotides are important because they play a critical role in epigenetics, gene regulation, and disease development. They are also the target of many DNA methylation and demethylation processes.
CpG dinucleotides are different from other dinucleotides because they are the only dinucleotides that are sites for DNA methylation and demethylation. They also have a high mutation rate due to the deamination of methylated cytosines.
CpG dinucleotides are commonly found in regions of DNA that are involved in gene regulation, such as promoter and enhancer regions. They are also found in high density in CpG islands, which are regions of DNA that have a high frequency of CpG sites.
CpG dinucleotides have been linked to several diseases, including cancer, autoimmune disorders, and neurological disorders. Aberrant methylation patterns of CpG dinucleotides have been associated with the development and progression of these diseases.