What You Need to Know

Key Concept Diagram

Epigenetic changes modify gene expression without altering the DNA sequence

DNA methylation typically silences gene expression by adding methyl groups to cytosine bases

Histone modification changes the packaging of DNA, affecting whether genes are accessible for transcription

Environmental factors including diet, stress, and exposure to chemicals can cause epigenetic changes

Some epigenetic changes can be passed on to subsequent generations (transgenerational epigenetics)

Key Vocabulary

Epigenetics

The study of heritable changes in gene expression that do not involve changes to the DNA sequence

DNA methylation

The addition of methyl groups to DNA that typically suppresses gene expression

Histone

A protein around which DNA is wrapped; modification of histones affects gene accessibility

Gene expression

The process by which information in a gene is used to produce a functional product such as a protein

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

Epigenetic changes differ from mutations because:

Epigenetic changes alter the DNA base sequence Epigenetic changes affect gene expression without changing the DNA sequence Epigenetic changes are always permanent Mutations only occur in non-coding DNA

Question 2

DNA methylation typically:

Increases gene expression Causes mutations Silences or reduces gene expression Replicates DNA faster

Question 3

Which environmental factor has been shown to cause epigenetic changes?

The speed of the wind Barometric pressure The colour of light Diet, stress, and chemical exposure

Epigenetics and Gene Expression