It may sound like an exotic vacation, but it honestly isn’t. This is a unique feature within our DNA where there are a large number of C’s followed by G’s. In a section of at least 200 base pairs, at least half of these have to be CG sites. Whenever there are large numbers of CpG islands, our cells are supposed to methylate these regions of our DNA. CpG islands are studied because they indicate where there might be mutations in our DNA.
Methylation is a process where additional methyl groups are added to DNA to turn the gene off permanently. Once the gene is silenced, it can’t make proteins any more. As a result, researchers are interested in studying CpG islands because of the link to cancer. This is part of an emerging body of research and science known as epigenetics, which aims to understand the environmental changes to DNA.