Question

1. Two approaches for correcting single-gene defects are gene therapy such as is discussed in Section 3-5D and the CRISPR–Cas9 system. Explain why the CRISPR–Cas9 approach can potentially provide more complete restoration of normal tissue function than gene therapy.

2. A certain mutant DNA polymerase is error-prone, tending to incor-porate C opposite a template A. When such a DNA polymerase repli-cates a segment of DNA containing an A · T base pair, what will be the DNA composition in the daughter cells after (a) one and (b) two rounds of cell division? Assume that DNA repair does not occur.

3. Explain why mutations are more likely to occur on the lagging strand than on the leading strand in eukaryotes.

Answer 1

CRISPR means Clustered Regularly Interspaced Short Palindromic Repeats, derived from bacterial defence mechanism and leads to the founded basis of  CRISPR-Cas9 genome. It is technology used to edit the genome of an organism and thus correcting gene defects by targetting specific sites of DNA for editing. with this advancements scientists are able to change or modify genes of the living system as well it has the capapbility to cure mutations that are fatal or life threating to the human beings.

However, gene therapy is a technique for curing or preventing the disease by the use genes. The main aim of this technique is to replace the faulty gene with the healthy a new gene or deactivating the mutant gene, or introducing a new gene which can help in combating against disorders.

AS CRISPR- Cas9 is efficient in cutting DNA strands by its own and thus doesnot need any cleaving or repairing enzymes and easily tarhet the DNA strand to lead the process. It has the capability to target mutiple sequences at one time so, it is better approach in providing complete restoration of normal tissues in the body as compared to gene therapy method where a vector is required to carry a gene and sometimes it is not able to target the site appropriately.

CRISPR/Cas9 is a method of genome editing. CRISPR used for gene therapy (or for any other gene editing attempts), and gene therapy could be done with any of several other methods.