(a)[4]
Outline the main principles involved in genetic engineering.
(b(i))[2]
Explain why a single infusion of gene-corrected stem cells is sufficient to cure the disease.
(b(ii))[2]
Explain why a promoter has to be transferred along with the desired gene.
(b(iii))[2]
A modified retrovirus is used to place the new gene into the DNA of the blood stem cells. State two ethical considerations of using a retrovirus for gene therapy.
(c)[3]
The gene therapy method used to cure ADA-SCID is not suitable for treating the genetic disorder called Huntington’s disease. A newer technique called gene editing could potentially be used instead to cure Huntington’s disease. Explain why gene editing is more suitable as a potential cure for Huntington’s disease.