Please explain methylation in a simple way. ?

CH(3): Methylation refers to the addition of a small molecule (methyl group = one carbon and 3 hydrogen) to another molecule. The addition of a methyl group can change the activity of whatever it was added on to. For example, dna methylation can cause the structure of dna to become more closed or compacted, and this can result in a gene being turned off. Methylation can be normal, or abnormal in disease.

Methylation: Methylation means putting a methyl group (1 carbon atom and 3 hydrogen atoms = 1 methyl group) onto a gene to either turn it on or turn it off. Turning the gene off is generally more important. SNPs (single nucleotide polymorphisms) in mehtylation genes MTHFR 677 and MTHFR 1298 are very common. The most noticeable effect outwardly is the production of neurotransmitters (brain chemicals).