List three applications of recombinant DNA technology.

Recombinant DNA technology mainly used to change the phenotype of an organism (host) when a genetically altered vector is introduced and integrated into the genome of the organism. So, basically, this process involves the introduction of a foreign piece of DNA structure into the genome which contains our gene of interest. This gene which is introduced is the recombinant gene and the technique is called the recombinant DNA technology. Application of recombinant DNA technology: Gene Therapy – It is used as an attempt to correct the gene defects which give rise to heredity diseases. Clinical diagnosis – ELISA is an example where the application of recombinant DNA technology. Recombinant DNA technology is widely used in agriculture to produce genetically-modified organisms such as Flavor Savor tomatoes, golden rice rich in proteins, Bt-cotton to protect the plant against ball worms and lot more.

Write down the principle involved in DNA finger-printing.

DNA is the genetic material in most of the living organisms and found to be present in the nucleus of the cell. Any piece of DNA sample found at a crime scene can be analysed for the level of polymorphism in the non-coding repetitive sequences. After the DNA profile is traced, it becomes easier to find the criminal by performing the DNA fingerprinting for the suspects. DNA fingerprinting is also useful in finding the parents of an unclaimed baby by conducting a paternity test on a DNA sample from the baby. Satellite DNA regions can be characterised as stretches of repetitive DNA which do not code for any specific protein. These non-coding sequences form a major chunk of the DNA profile of humans. They depict a high level of polymorphism and are the basis of DNA fingerprinting. These genes show a high level of polymorphism in all kind of tissues as a result of which they prove to be very useful in forensic studies.

Write a note on Bt cotton.

Bt cotton is genetically modified organisms which are resistant to the insect which harms cotton plant. Bacillus thuringiensis is a soil-borne bacterium. It has a toxic gene Bt-2 that can form cry protein. This protein is produced by Bacillus thuringiensis at a specific stage of its growth. Bt-2 gene isolated from the bacteria and is genetically engineered and inserted into the cotton plant. The cotton plant expressed this gene, which protects cotton from the infection of lepidopteran. The cry protein is toxic. Any insect feed on cotton, Bt-2 gene produces cry protein, which destroys the intestinal membrane of insects and results in the leakage of ions and small molecules. Finally, the death of an insect takes place. Bt cotton reduces the use of insecticides, which decreases the rate of environmental pollution and also the energy of farmers.

What is cryopreservation?

Cryopreservation is the technique of preservation of cells and tissue for a long period. The procedure involves cooling the cells, organs and tissues at ultra-low temperature (-196 0 C). It helps to preserve the cells and maintain cell viability. The discovery of cryopreservation has inspired using frozen semen instead of fresh semen. The old method of propagation is substituted by artificial insemination. In this method, the semen is collected from a superior bull, and the cows are inseminated.