Bt toxin gene has been cloned from the bacteria, and has been expressed in plants, to provide resistance to insects (without the need for synthetic insecticide), Bt toxin gene forms protein crystals, These crystals contain a toxic insecticidal protein. Bt toxin protein exists as inactive protoxin in the host, but once the insect ingests the inactive toxin, it is converted into active form of toxin, due to alkaline pH of the gut which solubilises the crystals, causing death of the insect

(i) BT cotton is genetically modified cotton.
(ii) It has been developed by introducing BT toxin gene to the cotton plant from a bacterium which is resistant to bollworms.
(iii) Grandfather was concerned about the well being of his friend and advised him to grow genetically modified, disease resistant variety od frop.

(i) Restriction Endonucleases.
(ii) Gel Electrophoresis.
(iii) T4 ligase.
(iv) Vector and competant host
(v) DNA delivery system.

Following are the advantages of recombinant Insulin:
(a) Recombinant Insulin can be prepared on a large scale without worrying about the source animal.
(b) Batch to batch consistency can be maintained, and quality can be maintained.
(c) Helps in preventing cruelty against animals.
(d) Chances of allergic reactions have been minimized.
(e) Chances of transmission of infection from source animals have been nullified.
(f) Recombinant Insulin has almost replaced animal-sourced Insulin from around the world.
(g) This paves the way for forms of Insulin, which need not be given through injections.

(1) Availability of Biochemicals;
(2) Gene Therapy;
(3) Molecular Diagnosis;
(4) Free crop yield
(5) Environmental Protection.
(6) Disease true crop yeild: Refer to Basis and Basics

Transgenic animals Transgenic animals are produced for the following purposes:
(i) Transgenic animals are designed to allow the study of how genes are regulated and how they affect the normal functions of the body and its developments e.g. Information is obtained as to how insulin has a role as growth factor.
(ii) Transgenic animals are designed to increase our understanding as to how genes control the development of diseases; they serve as models for human di eases.
(iii) Transgenic animals that produce useful biological compounds lure created by introducing a portion of the DNA that codes for that product, e.g.
\(\alpha \) -I antitrypsin is produced for curing emphysema.
(iv) Transgenic mice are being developed to test the safety of vaccines. e.g., polio vaccine has been tested on mice.

Transgenic animals are those animals which have their DNA manipulated to possess and express one/more foreign gene(s).
They are produced for the following purposes:
(i) Transgenic animals are designed to allow the study of how genes are regulated and how they affect the normal functions of the body and its development, e.g. information has been obtained as to how insulin hasnt a role as growth factor.
(ii) Transgenic animals that produce useful biological compounds are created by introducing a portion of the DNA that codes for the product, e.g. a-1- antitrypsin is produced for treating emphysema.
(iii) Transgenic animals are being developed to test the safety of vaccines, e.g. polio vaccine has been tested on transgenic mice.
(iv) Transgenic animals with more sensitivity to toxic substances are being developed to test the toxicity of drugs.

The mature/functional insulin consists of two polypeptide chains, coded by two genes.
The American Company, Eli Lilly, prepared the two genes or DNA sequences coding for the two polypeptide chains.
The genes were introduced into the plasmid of bacterium E.coli.
The bacterium produces the polypeptides which are secreted in the medium.
They are isolated from the medium and combined by creating disulphide bonds into functional insulin.
Since, genetically engineered insulin does not induce any immunological response, unlike insulin from other non-human sources, it is preferred.

Deletion of the gene for ADA causes ADAdeficiency, i.e. deficiency of adenosine deaminase, the enzyme which is crucial for the normal functioning of our immune system.
 ADA deficiency can be cured by:
(i) Bone marrow transplantation.
(ii) Enzyme replacement therapy in which functional ADA is given by injection.
(iii) Gene therapy, in which functional ADA cDNA is introduced into lymphocytes or into cells at early embryonic stage.

Nematode-resistant tobacco plants are produced through RNA interference. The process RNA interference (RNAi) involves silencing of a specific mRNA.
A complementary double-stranded RNA binds to the mRNA and prevents its translation.
The complementary! RNA for making the double stranded RNA comes either from an infection by RNA viruses or  mobile genetic elements, called transposons, which replicate through an RNA-intermediate.
The nematode-specific genes were introduced into the host plant by the use. of Agrobacterium vectors.
The introduction of DNA is such that it produced both sense and anti-sense RNA in the host cells.
These two RNAs are complementary to each other and hence form a double-strandedd RNA, which initiates the RNA interference and silencing of mRNA.
The parasite could not live in such a transgenic host that expresses the specific interfering double-stranded RNA;   so, the transgenic plant is protected from the nematode.

Nematode-resistant tobacco plants are produced through RNA interference. The process RNA interference (RNAi) involves silencing of a specific mRNA.
A complementary double-stranded RNA binds to the mRNA and prevents its translation.
The complementary! RNA for making the double stranded RNA comes either from an infection by RNA viruses or  mobile genetic elements, called transposons, which replicate through an RNA-intermediate.
The nematode-specific genes were introduced into the host plant by the use. of Agrobacterium vectors.
The introduction of DNA is such that it produced both sense and anti-sense RNA in the host cells.
These two RNAs are complementary to each other and hence form a double-strandedd RNA, which initiates the RNA interference and silencing of mRNA.
The parasite could not live in such a transgenic host that expresses the specific interfering double-stranded RNA;   so, the transgenic plant is protected from the nematode.