Epigenetics

Unlike mutations, epigenetic changes in genes can be the result of

• changes in the DNA base sequence

• methylation of the nucleotide cytosine

• a frameshift in DNA

• the addition of a methyl group to the nucleotide guanine

DNA methylation would alter gene expression by

• Measurably increasing gene expression

• Not changing gene expression

• Measurably decreasing expression

• Sometimes increasing and sometimes decreasing

Which of the following statements about DNA methylation is incorrect?

• It is associated with repression of transcription

• It involves the addition of a methyl group to a nucleotide

• Methylation is essential to normal development

• Methylation is permanent and cannot be reversed

State the name of the DNA base that is most commonly methylated

• Guanine

• Cytosine

• Adenine

• Uracil

Explain how a change in DNA methylation in a Tumor Suppressor Gene (TSG) can lead to colorectal cancer