Epigenetics

Question 1

What is the name of specialised proteins involved in gene regulation?

Answer 1

Histones

Question 2

What is the function of histones?

Answer 2

Organise and compact DNA strands into chromatin or protein/DNA complexes
Safeguard the DNA (make it available or not)

Question 3

What is epigenetics?

Answer 3

The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.

Question 4

What are the 3 main mechanisms that modify DNA?

Answer 4

1) DNA methylation
2) Modification of histones
3) Non-coding RNA

Question 5

How does methylation change gene expression?

Answer 5

Target specific points in the DNA molecule with a methyl group, which usually silences a gene

Question 6

What does DNA methylation involve?

Answer 6

The addition of a methyl group at the 5 position on the pyrimidine ring of cytosine (creating 5-methycytosine)

Question 7

How does the modification of histones change DNA gene expression?

Answer 7

Chromatin structure is changed by adding or subtracting a methyl or acetyl group
Methylation tightens up DNA, restricting access to genes
Acetylation unravels DNA, making genes more available for activation

Question 8

Why is heavy drinking an issue (gene expression)?

Answer 8

Epigenetic modifications in histones structure occur within the liver

Question 9

How can diet affect mental ability?

Answer 9

High fat low carb diet could open up chromatin and improve mental ability via histone deacetylase inhibitors

Question 10

Non-coding RNA regulates gene expression at the transcriptional and post-transcriptional level.
___% of the genome is transcribed into ________ ____.

Answer 10

90%
Non-coding RNA

Question 11

What % of the whole genome is translated into proteins?

Answer 11

2%

Question 12

DNA (de)methylation, chromatin remodeling and ncRNAs closely interact to form a …

Answer 12

Complex, multilayered regulatory system
That can dynamically fine-tune gene expression

Question 13

25% of the epigenetic variation between babies is due to fixed genetic changed. The other 75% is due to …

Answer 13

interactions between the babies’ environment in the womb and genetic information passe down from the parents

Interaction of genetic differences and prenatal environment

Question 14

Inappropriate nutrition in utero leads to

Answer 14

a) Distubance of cell proliferation (irreversible changes in tissue structure)
b) Alterations in patterns of epigenetic remodelling
c) Changes in physiological function

Question 15

Minimising adult horse obesity is dependent on minimising 2 counterbalancing risks:

Answer 15

1) The development of poor metabolic capacity (pre-programming
2) The development of excess metabolic load (environment)

Question 16

Why can poor in utero nutrition lead to a foal that is more predisposed to obesity?

Answer 16

The adaptive response of the foetus is to maximise uptake of nutrients, as isn’t used to good quality nutrition, therefore is biologically born prepared to survive a ‘poor’ diet