DNA methylation is the only known natural modification of DNA.It affects
A)adenine bases.
B)guanine bases.
C)cytosine bases.
D)thymine bases.

Question

Quizplus · Accepted Answer

DNA methylation affects cytosine bases where a methyl group is added to the fifth carbon of the cytosine ring. This modification regulates gene expression and plays a role in processes such as embryonic development, X-chromosome inactivation, and genomic imprinting. There is no known natural modification of adenine, guanine or thymine bases in DNA.

DNA Methylation Is the Only Known Natural Modification of DNA