Epigenetics

Epigenetics refers to the changes in gene expressesion - transcription

through the way DNA is wrapped around the histone changes

• Histone modification

• Acetylation

• Methylation

Histone modification

changing shape (loose or tight)

adding something to histones

Histone acetylation

The addition of an acetyl group to histone → reduces the attraction between histones and DNA, DNA is loosely around histone

Allowing RNA polymerase greater access to the gene, resulting in increased transcription → Increase gene expression

DNA Methylation

Add methyl group to DNA, occurs at CpG site - where cytosine is next to guanine → blocking access to gene for RNA Polymerase → decrease in in transcription (inhibits gene expression)

Demethylation may also occur, which is the opposite (enhances gene expression)

Epigenetic Factors

Epigenetic change is a regular and natural occurrence, but can be influenced through Age, the Environment/lifestyle and Disease states

• severe stress

• Nutrition

• Drugs/toxins