Epigenetics

Question 1

What is epigenetics?

Answer 1

Epigenetics is the study of change in gene expression without altering the underlying genetic code. These changes are natural but are influenced by factors such as age, environment, disease and lifestyle.

Question 2

What are the two main systems involved in epigenetic change?

Answer 2

DNA methylation and histone modification.

Question 3

What happens if DNA is methylated? (DNA methylation)

Answer 3

Methyl group is added to the 5th carbon atom of a cytosine ring, results in genes being switched off or suppressed.

Question 4

What may the addition of an acetyl group do to histone proteins? (Histone modification)

Answer 4

Acetylation may cause the histones to become less tightly bound to DNA, exposing regions of DNA and increasing gene transcription. Deacetylation will have the opposite affect and cause the DNA to be tightly bound to the histone, decreasing the probability of gene transcription.

Question 5

Example of an external stimulus?

Answer 5

BPA - an additive used in plastic to maintain flexibility. It has been linked to cancer and other diseases.

Question 6

How is epigenetics studied in twins?

Answer 6

Identical twins have the same genetic make up and are studied to see how environmental differences affect gene expression. Epigene tags are analysed to identify differences in traits, health and disease.