Epigenetics

Question 1

What is the literal meaning of epigenetics?

Answer 1

On top of genetics

Question 2

What’s the definition of epigenetics?

Answer 2

Processes that induce long term stable changes in gene activity without affecting the DNA sequence

Question 3

What are the main epigenetic processes?

Answer 3

DNA methylation
Histone modification
Non-coding RNA

Question 4

What happens in DNA methylation?

Answer 4

Cytosine is methylated to 5-methyl-cytosine

Question 5

What are the theee types of methylated DNA?

Answer 5

Unmethylated, hemi-methylated and fully methylated.

Question 6

What methylation signals transcriptionally active DNA?

Answer 6

Unmethylated

Question 7

What methylation makes DNA transcriptionally inactive?

Answer 7

Methylated

Question 8

What is the model for DNA methylation causing inhibitions of gene expression?

Answer 8

1) DNA methylation blocks transcription factor binding
2) MeCP2 bonds methylated DNA preventing RNA polymerase binding

Question 9

How does passive demethylation occur?

Answer 9

-Thought to passively occur through passive mechanism such as replication

Question 10

How does active demethylation occur?

Answer 10

Active demethylation occurs due to Tet1 (ten-eleven translocase 1) converts 5 methylcytosine to 5 hydroxyl cytosine. Then deamination or oxidation returns it back to cytosine.