Gene therapy is a form of . a) selective breeding b) artificial selection c) cloning d) genetic engineering

D) Genetic Engineering

Explanation:

Gene therapy is a type of genetic engineering because in gene therapy we have to manipulate the gene for our good.

There are three types of gene therapies:

1) Gene augmentation therapy

2) Gene knock out therapy

3) Gene silencing therapy

Gene augmentation therapy: In this type of gene therapy, the mutated gene which is non functional is retained in the genome and a functional copy of the gene is introduced into the genome.

Gene knock out therapy: In this approach the mutated/non-functional gene is replaced by a functional copy of the gene in the genome.

Gene silencing therapy: In this therapy, hyperactive genes like cancerous genes are silenced by introducing their miRNA gene in the genome.