CG Dinucleotides of class II MHC genes are mutation hot-spots.

DNA methylation of human class II genes of the Major Histocompatibility Complex (MHC) was correlated with gene expression and methyl-related CG → TG and CG → CA changes. It was found that cytosine methylation of the CG dinucleotides of MHC class II genes should be involved in generating a fraction of nucleotide polymorphism, rather than in controlling transcription.