(i) Dolly was the first mammal (sheep) Clone developed by Ian Wilmot and Campbell in 1997.
(ii) Dolly the transgenic clone was developed by the nuclear transfer technique and the phenomenon of totipotency.
(iii) Totipotency, refers to the potential of a cell to develop different cells, tissues, organs and finally an organism.
(iv) Dolly was the first animal to be cloned from a differentiated somatic cell taken from an adult animal without the process of fertilization.

(i) Gene therapy:
1. Gene therapy is the treatment of heredity disorders by replacing a faulty gene by a normal healthy functional gene.
(ii) The first clinical gene therapy was given in 1990 by French Anderson to a four year old girl with adenosine deaminase (ADA) deficiency.
(iii) The lymphocytes from the blood of the patient are removed and grown in a nutrient culture medium.
1. A healthy and functional human gene, ADA cDNA encoding this enzyme is introduced into the lymphocytes using a retrovirus.
2. The genetically engineered lymphocytes are subsequently returned to the patient.
3. These cells are not immortal, the patient requires a periodic infusion of such genetically engineered lymphocytes.

S.No.	SOMATIC CELL GENE THERAPY	GERMLINE GENE THERAPY
i.	Therapeutic genes transferred into the somatic cells.	Therapeutic genes transferred into the germ cells.
ii.	Introduction of genes into bone marrow cells, blood cells, skin cells, etc.,	Genes introduced into eggs and sperms.
iii.	Will not be inherited in later generations.	Heritable and passed on to later generations.

(i) Genetic immunization by using DNA vaccines is a novel approach that came into being in 1990.
(ii) The immune response of the body is stimulated by a DNA molecule.
(iii) A DNA vaccine consists of a gene encoding an antigen protein, inserted on to a plasmid, and then incorporated into the cells in a target animal.
(iv) DNA instructs the cells to make antigenic molecules which are displayed on its surfaces. This would evoke an antibody response to the free floating antigen secreted by the cells.
(v) The DNA vaccine cannot cause the disease as it contains only copies of a few of its genes.
(vi) DNA vaccines are relatively easy and inexpensive to design and produce.
(vii) Vaccines produced by these new techniques have definite advantages like producing target proteins, long lasting immunity and trigger immune response only against specific pathogens with less toxic effects.

1. Yes the test ELISA helps.
2. ELlSA stands for Enzyme linked lmmuno Sorbent Assay.
3. It is used for the detection of (HIV) AIDS disease.
4. ELISA is based on the principle of antigen antibody interaction, by pathogen can be detected by the presence of antigens (Proteins, glycoproteins etc). or by detecting the antibodies synthesized by the host against the pathogen.
5. Thus it helps to identify the infection of HIV leads to AIDS.
6. The foreign DNA that is introduced is called the transgene and the animals that are produced by DNA manipulations are called transgenic animals or the genetically engineered or genetically modified organisms.

1. The foreign DNA that is introduced is called the transgene and the animals that are produced by DNA manipulations are called transgenic animals or the genetically engineered or genetically modified organisms.
2. Transgenic animals are also used for producing products useful for mankind. E.g: Transgenic cow (rosie), which produced human protein enriched milk (2.4 g/L).
3. The milk contained the human alpha lactalbumin and was nutritionally a more balanced product for human babies than natural cow's milk.

1. Gene therapy would be a better option because it has the potential to completely cure the patient.
2. It is because the correct gene once introduced in the patient; can continue to produce the correct protein enzyme.
3. Enzyme therapy does not offer permanent cure as it needs to be given to the patient on regular basis.
4. It is also more expensive.

1. ELISA is based on the principle of antigen antibody interaction. Any infection caused by a pathogen can be detected by the presence of antigen (proteins, glycoproteins etc) or by detecting the antibodies synthesized against pathogen in the body fluid (blood) of the host/ person.
2. Yes one can use antibody against the enzyme that is responsible for the metabolism of phenylalanine to develop ELISA based on the diagnostic technique.
3. The patient in which the Enzyme, Protein complex is absent would give a negative result in ELISA when compared to the normal individual.

1. Production of insulin by recombinant DNA technology started in the late 1970s.
2. This technique involved the insertion of human insulin gene on the plasmids of E. coli.
3. The polypeptide chains are synthesized as a precursor called pre-pro insulin, which contains A and B segments linked by a third chain (C) and preceded by a leader sequence.
4. The leader sequence is removed after translation and the C chain is excised, leaving the A and B polypeptide chains.
5. Insulin was the first eyer pharmaceutical product of recombinant DNA technology administered to human. In 1986 human insulin was marketed under the trade name humulin.

(i) Polymerase chain Reaction
(ii) In this process, multiple copies of the gene/ DNA of interest are synthesized in vitro using two sets of primers.
(iii) Primers are the chemically synthesized obligonucleotides that are complementory to the regions of DNA strands, where they will be annelated
(iv) The two strands of DNA have been separated by denaturation.
(v) The enzyme DNA polymerase extends the primers using the nucleotides provided in the medium on the genomic DNA as template.
(vi) To achieve repeated amplification, a thermostable DNA polymerase, called Taq polymerase obtained from Thermus aquaticus is used; it can withstand the high temperature used for the denaturation of DNA.

(i) Two sets of primers and the enzyme DNA polymerase are required in each cycle of  Polymerase chain reaction.
(ii) Role of primers and DNA polymerase Primers are necessary to start the functioning of DNA polymerase.
1. DNA polymerase extends the primers using the nucleotides provided in the reaction and the genomic DNA as the template.
2. The segments of DNA can be amplified to approximately billion times.
(iii) DNA polymerase used in PCR reaction is known as Tag polymerase, which is obtained from a bacterium Thermus aquaticus.