BRAINCAKEEpigenetics
Epigenetics involves heritable changes in gene function, without changes to the base sequence of DNA. These changes are caused by changes in the environment that inhibit or activate transcription.
DNA in the nucleus is wrapped around proteins called histones, forming chromatin. Chemical groups (tags) can be attached to the DNA and to the histones. Together, these tags make up the epigenome of the cell. Unlike the DNA base sequence, which is fixed, the epigenome is flexible and can respond to the environment.
The epigenome controls how tightly the chromatin is packed:
• If chromatin is highly condensed, transcription factors and RNA polymerase cannot reach the DNA, so transcription is inhibited.
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More in Control of Gene Expression
- Stem Cells in Treating Disease
- Transcription Factors
- Oestrogen and the Initiation of Transcription
- RNA Interference (siRNA and miRNA)
- DNA Methylation
- Histone Acetylation
- Epigenetics and Disease
- Benign and Malignant Tumours
All 18 lessons in Control of Gene Expression · All AQA A-level Biology topics