Supercharge your learning!

Use adaptive quiz-based learning to study this topic faster and more effectively.

DNA methylation

DNA can be modified by adding methyl groups ($$\ce{CH3}$$) to cytosine. This is called DNA methylation. Highly methylated genes cannot be expressed.

DNA methylation occurs in eukaryotes and prokaryotes. It is usually a permanent change to the DNA, but it is reversed when zygotes form.

DNA methylation prevents cells from reverting to stem cells after differentiation.

Changing the chromosomal structure can alter the gene expression of several genes at once.

A methyl group (a carbon with three hydrogens) is attached to cytosine to form methylcytosine.
A methyl group (a carbon with three hydrogens) is attached to cytosine to form methylcytosine.