20.4: Epigenetic control of gene expression Flashcards
Epigenetics
Explains how the environment influences can subtly alter the genetic inheritance of an organisms offspring
Epigenome
A second layer around DNA made up of chemical tags which determines the shape of the DNA-histone complex.
The specific protein to which DNA is attached has 2 possible effects
- acetylation of histones leading to the activation or inhibition of a gene
- methylation of DNA by attracting enzymes that can add or remove methyl groups
Increased acetylation and decreased methylation effect
Less condensed which means that the gene is accessible
Decreased acetylation and increased methylation effect
More condensed which means the gene is inaccessible
Condensed in relation to DNA
tightly packed
Acetylation
Addition of an acetyl group
Methylation
Addition of a methyl group to a molecule
Epigenome is…
flexible
DNA code is …
fixed
Epigenome’s tags respond …
to environmental changes
Affect of environmental factors on chemical tags
They can cause the chemical tags to adjust the wrapping and unwrapping of the DNA so genes switch on and off
Epigenetics and disease
Epigenetic changes are are part of normal development and health but can also be responsible for certain diseases
Epigenetic therapy
Epigenetic treatments counteract epigenetic changes
siRNA
Small interfering RNA
