| Applications | Functions/Example |
| Bt cotton | Bt toxin as produced by Bacillus thuringiensis has been cloned in bacteria and been expressed in plants to provide resistance to insects without the need for insecticides in effect created a bio-pesticide. Examples are Bt cotton, corn, rice, tomato, potato and soyabean etc. |
| Adenosine deaminase deficiency | The first gene therapy was done in a four year old girl suffering from the disorder called SCID that arises due to deficiency of Adenosine deaminase (ADA) deficiency. |
| RNAi | RNAi is a naturally occurring mechanism that leads to the “silencing” of genes. In consequence, the respective protein is no longer synthesized. In nature, this mechanism is used for the regulation of specific genes and is also applied as a defense against viruses. |
| PCR | (a) It helps to detect very low concentration of bacteria or virus at the time when the symptoms of the disease are not visible by amplification of their nucleic acid. (b) PCR is now routinely used to detect HIV in suspected AIDS patient. (c) It is being used to detect mutations in genes in suspected patients too. (d) It is a powerful technique to identify many other genetic disorders. |