Epigenetics

Question 1

What does epigenetics refer to?

Answer 1

Factors that make genes more or less likely to be expressed, without changing the genes themselves.

Question 2

What is your genome?

Answer 2

Your DNA code.

Question 3

What is your epigenome?

Answer 3

The sum of all the factors that determine where, when, and which genes are ‘switched on’ or expressed.

Question 4

How does the epigenome control gene activity?

Answer 4

It helps determine which genes are active in a cell, and therefore which proteins will be produced.

Question 5

What can happen if the epigenome is abnormal?

Answer 5

Certain cells may be abnormal, which could result in disease.

Question 6

How are genes regulated epigenetically?

Answer 6

Through changes in chromatin.

Question 7

What is chromatin?

Answer 7

Coiled DNA and histone proteins, forming a tangled network when a cell is not dividing.

Question 8

How can gene expression change in relation to histones?

Answer 8

It may change if the way DNA is wrapped around histones changes.

Question 9

What is acetylation?

Answer 9

The addition of an acetyl group (CH₃CO) to histones, decreasing DNA-histone attraction, relaxing chromatin, and enhancing gene expression.

Question 10

How does acetylation affect RNA polymerase?

Answer 10

It allows RNA polymerase to access and transcribe more DNA.

Question 11

What is methylation?

Answer 11

The addition of a methyl group (CH₃) to histones or DNA, often at CpG sites, which can inhibit or sometimes enhance gene expression.

Question 12

How does methylation of DNA affect gene expression?

Answer 12

It restricts RNA polymerase access, inhibiting gene expression.

Question 13

How can methylation of histones affect gene expression?

Answer 13

It can either increase or decrease gene expression depending on where the methyl group is added.

Question 14

How can the environment change a person’s epigenome?

Answer 14

Through exposure to stress, nutrition, toxins, or drugs.

Question 15

How can epigenetic differences be inherited?

Answer 15

Variations in gene expression levels can contribute to phenotypic variation among individuals.