Epigenetic Modification

Question 1

What is Epigenetic Modification ?

Answer 1

Study of changes in gene function that are miotically and meiotically heritable and does not entail a change in DNA sequence

Question 2

Examples of Epigenetic Modification

Answer 2

Altercation ( Addition/removal of functional group of nucleosomes) Histone mofocaition , including phophorlyation , methylation

Alteraction of DNA : DNA methylation ( repression of transcription)

Question 3

DNA methylation

Answer 3

By addition of methyl (CH3) GROUP TO DNA

Modifying the function of the genes affecting gene expression

Question 4

Effect of DNA methylation

Answer 4

Physical block for binding of transcription proteins

Methylated DNA binds to methyl -CPG binding in CPG island

Question 5

Some good uses of DNA methylation

Answer 5

Works in conjuction with other gene expression control mechanism

Combination ensures uneeded eukaryotic genes can be repressed to a high degree

Question 6

Role of DNA methylation

Answer 6

The methyl groups on methyl cytosine inetder beinding with proteins required for transcription initiation

Cells contain repretore of proteins bind only to methylated DNA

Question 7

What is Genomic imprinting

Answer 7

Mammalian cells are diploid containing one set of genes inherited from mother and father

Inherited gene is active , maternally gene is silent vice/versa

DNA methylation is used to distuing two copies of gene that maybe identical .

Question 8

How does Histone Modification influence DNA methylatiion ?

Answer 8

DNM3; binds to H3 histone tails and recruit DNM +3a and Dnm3b to methylate DNA

Precence of active histone modifications prevails methylation .