What is gene therapy? Explain the types. Add a note on its applications?

Explanation

Gene therapy : The technique of curing genetic diseases by replacing the defective genes by normal genes is called gene therapy W.F. Anderson is regarded as the father of gene therapy.
Type of gene therapy:
There are two main types of gene therapy, namely somatic cell gene therapy and germ line gene therapy.
(a) Somatic cell gene therapy: It is the replacement of the defective gene by a normal gene in somatic cells of the body. This therapy hepls for treating the defective organs or tissues parts such as blood cells, liver cells, skin cells, lung cells etc. The genetic defects can be rectified only in that individual. The replaced gene is not transmitted to the next generation. The diseases like SCID [ Severe combined immuno deficiency], Cystic fibrosis, Haemophilia, Cancer etc can be cured by somatic cell gene therapy.
(b) Germ line gene therapy : It is the replacement of defective genes by normal genes in germ cells to rectify the genetic disorders. This includes gene therapy in sperms, eggs. zygotes or early embryos. Any change made in the germ cells by gene therapy will be transmitted to the offspring.
Applications of gene therapy.
1. The genes causing genetic disease can be removed and normal genes can be inserted.
2. Non -functional organs can be made functional.
3. Severe combined immuno deficiency [SCID] disease can be cured by introducing normal Adenosine deaminase gene.