CPG ISLAND

CpG island: translation

(= CG island)

Region of genomic DNA rich in the dinucleotide C-G. Methylation of the C in the dinucleotide is maintained through cell divisions, and profoundly affects the degree of transcription of the nearby genes, and is important in developmental regulation of gene expression.There are around 30,000 CpG islands in a typical mammalian genome, and these tend to be undermethylated and upstream of housekeeping genes.