NSG 5531 CHAPTER 6 EPIGENETICS AND DISEASE| VERIFIED AND
ACCURATE | 2026 UPDATE
Chapter 6
Epigenetics and Disease
Chapter Objectives
Chapter Objectives
Identify the three major types of epigenetic modifications.
Describe differential epigenetic modification and its role in embryogenesis.
Discuss evidence supporting the epigenetic effects on disease risk.
Identify strategies for reversing epigenetic modifications.
Describe the process of imprinting.
Identify diseases that can be caused by abnormal imprinting patterns.
Overview of Epigenetics Mechanisms
Overview of Epigenetics Mechanisms
Epigenetic Mechanisms
(1 of 3)
Epigenetic Mechanisms
(1 of 3)
DNA methylation
Is the attachment of a methyl group to a cytosine base that is followed by a guanine base; also known as CpG
dinucleotide.
Causes a gene to become transcriptionally inactive or silent.
When DNA sequence in the promoter region of a gene becomes heavily methylated, DNA is less likely to be
transcribed into messenger RNA (mRNA).
Aberrant methylation: Is the silencing of tumor-suppressor genes in cancer development.
Is a key component of X-inactivation.
Epigenetic Mechanisms
(2 of 3)
DNA hydroxymethylation
Most common in cells undergoing epigenetic transition.
Hydroxymethyl group affixes to C5 of cytosine.
Methylation loss in embryonic development
Epigenetic Mechanisms
, (2 of 3)
Speaker Notes
Figure 06-02. CpG site. A CpG site is the 5′-C-phosphate-G-3′ sequence of nucleotides, shown on one DNA
strand (yellow). On the reverse DNA strand (blue), the complementary 5′-CpG-3′ site is shown. A C-G base-
pairing between the two strands is also shown (right). (From Moini J, Avgeropoulos NG, Samsam M. Li–
ACCURATE | 2026 UPDATE
Chapter 6
Epigenetics and Disease
Chapter Objectives
Chapter Objectives
Identify the three major types of epigenetic modifications.
Describe differential epigenetic modification and its role in embryogenesis.
Discuss evidence supporting the epigenetic effects on disease risk.
Identify strategies for reversing epigenetic modifications.
Describe the process of imprinting.
Identify diseases that can be caused by abnormal imprinting patterns.
Overview of Epigenetics Mechanisms
Overview of Epigenetics Mechanisms
Epigenetic Mechanisms
(1 of 3)
Epigenetic Mechanisms
(1 of 3)
DNA methylation
Is the attachment of a methyl group to a cytosine base that is followed by a guanine base; also known as CpG
dinucleotide.
Causes a gene to become transcriptionally inactive or silent.
When DNA sequence in the promoter region of a gene becomes heavily methylated, DNA is less likely to be
transcribed into messenger RNA (mRNA).
Aberrant methylation: Is the silencing of tumor-suppressor genes in cancer development.
Is a key component of X-inactivation.
Epigenetic Mechanisms
(2 of 3)
DNA hydroxymethylation
Most common in cells undergoing epigenetic transition.
Hydroxymethyl group affixes to C5 of cytosine.
Methylation loss in embryonic development
Epigenetic Mechanisms
, (2 of 3)
Speaker Notes
Figure 06-02. CpG site. A CpG site is the 5′-C-phosphate-G-3′ sequence of nucleotides, shown on one DNA
strand (yellow). On the reverse DNA strand (blue), the complementary 5′-CpG-3′ site is shown. A C-G base-
pairing between the two strands is also shown (right). (From Moini J, Avgeropoulos NG, Samsam M. Li–
