Question

13. Epigenetics basically refers to changes in gene activity without a change in base content of DNA. Think of a multicellular eukaryotic organism such as a human. Please write down 2 different genomic events in humans that may be associated with epigenetic regulation.

Answer 1

During epigenetic change, there is no change in the content of the DNA, but it leads to the gene activity. This means that gene regulation is distorted and disturbed but there is no change in the gene sequence or the DNA content. This means that it can lead to increased or decreased expression of a gene which leads to improper activation of an enzyme or hormone.

i) One of them is the progression of cancer which is under the epigenetic control. In this there is epigenetic modification cause to the DNA of the tumorous or cancer cell. This does not lead to any type of change in the sequence of the DNA nucleotide, but it tends to alter the expression of the DNA. One of the examples is the accumulation of the DNA. When the DNA damage or error is not repaired and it tends to accumulate, the excess DNA damage without the change in the nucleotide leads to errors during DNA replication. Hence one of them in humans is the epigenetic alteration which tends to accumulate the errors that is caused inability to repair damaged DNA and this causes cancer.

ii) The diabetes in another effect of epigenetic regulation in humans where there is no change in the DNA base nucleotide sequence, but it tends to still alter the gene expression. This is the most common cause of type-2 diabetes. When there is defect in the pancreatic beta cell, it alters the ability to produce the insulin and hence the gene expression reduces or stops insulin production. Hence this leads to occurrence of type-2 diabetes.