Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
Chapter 16: Gene regulation in eukaryotes II: epigenetics
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, Genetics summary – VU BMS 2020/2021
Simone Zweers
Reference: Brooker, Genetics: Analysis and prinicples, 7th edition
- Epigenetics is a field of genetics that explores changes in gene expression that may be
permanent over the course of an individual’s life but are not permanent over the course
of multiple generations
- Epigenetic changes responsible for the establishment and maintenance of gene
activation/repression enable cells to remember past events
16.1: Overview of epigenetics
- Epigenetic effect begins with an initial event that causes a change in gene expression
change must be passed from cell to cell and must not involve a change in the DNA
sequence
- Embryonic development genes that will become muscle cells are inhibited by
epigenetic changes like DNA methylation adult muscle cell will not express the
inhibited genes
- Other epigenetic changes may be reversible during the life
- Epigenetics is the study of mechanisms that leas to changes in gene expression that
can be passed from cell to cell and are reversible, but do not involve a change in the
sequence of DNA. This type of change may also be called an epimutation – a heritable
change in gene expression that does not alter the DNA sequence
- (Transgenerational) epigenetic inheritance when the change is passed from parent to
offspring via gametes
Different types of molecular changes underlie epigenetic gene regulation
- Most common are DNA methylation, chromatin remodeling, covalent histone
modification, histone variants, feedback loops
- They can also be involved in non-epigenetic changes (transient)
Epigenetic changes
may be targeted to specific genes by transcription factors or non-coding RNAs
- Transcription factors may bind to a specific gene and initiate a series of events that lead
to an epigenetic modification
- They recognize specific sites in the genome
and recruit proteins, like histone-modifying
enzymes and DNA methyltransferase to
those sites (a)
- Or ncRNAs are involved in establishing an
epigenetic modification can act as
bridges between specific sites in the DNA
and proteins that alter chromatin or DNA
structure (b)
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