Transgenic Animals Notes – Biotechnology And Its Application

CBSE Class 12- Biotechnology And Its Application – Transgenic Animals: When a foreign gene inserts into the genome of the animals to alter its DNA or the animals with a modified genome are Known as Transgenic Animals. It is a method that helps to improve the genetic traits of targeted animals. Transgenic animals are also called genetically modified organisms.

What are Transgenic Animals?

Transgenesis is defined as a foreign gene of some required features which is inserted into the genome of the animal to alter its DNA. It is a method done to improve the genetic traits of the target animal. These animals consist of modified genomes.

The animal genome is known as the transgenic and the foreign gene is known as a transgene. These genes are passed to successive generations. The Selective breeding method is used for the improvement of genetic traits. Animals with required features were mated to produce new individuals with improved genetic features. However, this technique is not cost-effective and also time-consuming that’s why it was replaced by recombinant DNA technology. Examples of Transgenic Animals – Dolly Sheep, Transgenic mice, and so on.

Methods for the Creation of Transgenic Animals

Physical Transfection

This is the first method in which the interested gene is directly injected into the pronucleus of the fertilized ovum. This method was effective in mammals and was also applicable to a variety of species.

Chemical Transfection

The chemical method of gene transfection consists of transformation. In this method, when calcium phosphate was present the target DNA is taken up. Calcium phosphate co-precipitates or DNA takes DNA uptake.

Viral Vectors

Viral vectors are viruses that have the ability to infect the host cell. They transfect rDNA into the animal cells.

Bactofection

It is a method in which with the help of bacteria the interested gene is transferred into the target gene.

Retrovirus-mediated Gene Transfer

The gene is usually transferred by means of a vector and used as vectors to transfect the interested gene into the target genome.

Examples of Transgenic Animals

Following are the example of transgenic animals:

Transgenic mice

By injecting DNA into the oocytes or the one-two-celled embryos which were taken from the female mice these transgenic animals are developed. After it is injected into the DNA then the embryo is implanted into the uterus of the female receptor.

Dolly Sheep

It was the first mammal that was cloned from an adult cell. The udder cell of a six-year-old girl Finn Dorset white sheep was injected into an unfertilized egg which was from a Scottish Blackface ewe whose nucleus has been removed. The cell was made to fuse by the electrical pulses and after the fusion of the nucleus cell with the egg the embryo was cultured for 6 to 7 days. It was implanted into another Scottish Blackface ewe which gave birth to transgenic sheep named Dolly.

Applications of Transgenic Animals

1. Biological Products: Biological products like some nutritional supplements and medicines are obtained from transgenic animals. Some medicines treat diseases like phenylketonuria.
2. Safety of Vaccines: Some model organisms are used for the testing of the safety of vaccines before they can be injected to human beings. Monkeys are used for testing before they can be used in humans.
3. Study of Diseases: They are used to study the role of genes in the development of diseases. Model organisms are used for the research purpose and for the development of medicines.

FAQs on Trangenic Animals

Q1: Define Transgenic Animals.

Answer: 

Transgenic animals are defined as when a foreign gene is inserted into the genome of the animals to alter its DNA or the animals with the modified genome.

Q2: What do you mean by Chemical Transfection Method?

Answer: 

In this method, when calcium phosphate was present the target DNA is taken up. The chemical method of gene transfection consists of transformation.

Q4: Write the application of Transgenic Animals.

Answer:

The following are the applications of transgenic animals:

• Study of Diseases
• Safety of Vaccines
• Biological Products

Q5: What do you mean by Physical Transfection Method?

Answer:

It is the first method in which the interested gene is directly injected into the pronucleus of the fertilized ovum.