D2.2.6 (HL)—Epigenetic tags
Epigenetic tags such as DNA methylation and histone methylation alter chromatin access and regulate transcription in cells and tissues over time.
- Syllabus
- First assessment 2025
- Objective
- D2.2.6
- Level
- HL
Exam analysis
Chance of appearing3%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–2
Common command terms
- Outline
- Suggest
- Explain
Scoring notes
- Common mistake
- Describing histone methylation when the question specifically asks about DNA methylation.
Recent exam appearances
November 2025Paper1B ["HL"] · TZ11(c)[ 2 ]D2.2.6 (HL)—Epigenetic tags
May 2025Paper1A ["HL"] · TZ220[ 1 ]D2.2.6 (HL)—Epigenetic tags
May 2019Paper2 ["HL"] · TZ22(b)(ii)[ 1 ]D2.2.6 (HL)—Epigenetic tags
May 2019Paper2 ["HL"] · TZ22(b)(i)[ 2 ]D2.2.6 (HL)—Epigenetic tags
Practice this objective
Coverage 2019–2025 · Updated 16 Jul 2026
Concept essentials
- Promoter DNA methylation usually represses transcription.
- Histone methylation can alter chromatin accessibility.
- Different methylation patterns can be associated with tumour cells.
- Epigenetic tags change gene expression without changing DNA sequence.