Question

Epigenetic changes

		a.results in unstable phenotypes.
		b.requires DNA mutations.
		c.are due to distortions in the DNA helix.
		d.can be dependent on whether the promoter regions for genes are available for RNA polymerase.
		e.are the same for all cells in an individual.

Answer 1

d. can be dependent on whether the promoter regions for genes are available for RNA polymerase.

Epigenetics involves heritable changes in DNA without affecting the DNA sequence. The pattern can be different for different cells in an individual. Epigenetics may cause silencing of genes in one cell while activation of Gene expression in other cells. This can be explained on the basis that promoter regions are hypermethylated which renders the RNA polymerase inaccesible to these regions leading to silencing of the downstream genes. In case of hypomethylated promoter regions, RNA polymerase has easy access to these regions leading to activation of downstream genes.