Transgenic Animals - Methods, Examples and Applications

What are Transgenic Animals?

Transgenic animals are organisms within which foreign genes have been purposely incorporated into their genome using recombinant DNA technology. This procedure is referred to as transgenesis, and with it, scientists can explore gene function and expression, produce pharmaceuticals, and enhance desirable characteristics in animals

The development of transgenic animals was initiated in the last century, and the creation of the first transgenic mouse took place in 1981. Since then, with the increase in applications of genetic engineering, many transgenic species have been developed for different purposes in both research and industry.

Transgenic animals are one of the important frontiers in modern science and agriculture. They are used in biomedical research to understand diseases, in the production of pharmaceuticals producing therapeutic proteins, and in agriculture to improve livestock and crop traits.

Methods for Creating Transgenic Animals

Various methods are used to introduce foreign genes into the host genome, depending on the species and purpose. These techniques ensure stable gene integration and expression. Some of the common methods of creating transgenic animals are:

Biological Methods

• Bactofection: Bacteria are used to deliver genetic material into animal cells. In this method, bacteria are engineered to contain the desired gene, which is then transferred into the target animal's cells.

• Viral vectors: The use of viruses to deliver new genes into the animal genome. Examples include retroviruses and adenoviruses engineered to transfer genetic material without causing disease.

Physical Methods

• Electroporation: An electric pulse makes transient pores in plasma membranes, DNA is forced into cells in this way.

• Microinjection: DNA is directly injected into the nucleus of a cell using a fine needle.

Chemical Methods

• Lipofection: DNA is encapsulated in liposomes. The enveloped DNA is then more easily taken up by target cells.

• Calcium phosphate transfection: Calcium phosphate is used to make a precipitate with DNA the cells then take up the DNA with the precipitate.

Comparison of Transgenic Techniques

Principle of Transgenesis

Transgenesis is the insertion of foreign genes into an animal's genome. Several methods exist for accomplishing this, each with its advantages and challenges. The following steps form the foundation of transgenic technology and help in the development of genetically modified organisms.

Gene selection: It is the first step that involves identifying and isolating genes responsible for the desired trait from the source organism.

Vector construction: The selected gene is inserted into a cloning vector that can transfer and integrate the gene into the genome of the host organism.

Gene expression: After the integration, the trans gene is expressed in the host organism, resulting in the production of the desired protein or trait.

Applications of Transgenic Animals

• Biomedical Research: Transgenic animals are extensively used to study diseases, mostly used in the development of their treatments and to study the functions of genes.

• Pharmaceutical Production: Therapeutic proteins and other pharmaceuticals can be produced by transgenic animals, hence providing efficient, appropriate, and cheap ways to produce transgenic animals.

• Agriculture: Improving livestock strains, for example, growth rate and disease resistance, which improve productivity and food security.

• Disease Modeling: Transgenic animals can serve as model animals in the study of human diseases. They help researchers to get more insight into disease mechanisms as well as look for cures for some of the diseases.

• Conservation Efforts: Transgenic animal techniques may be used to conserve endangered species by increasing genetic variation and increasing their resilience.

Transgenic Animals Practice Questions for NEET

Q1. Which of the following statements accurately describes transgenic animals?

1. All cells of transgenic animals contain foreign RNA.

2. Some cells of transgenic animals contain foreign DNA.

3. All cells of transgenic animals contain foreign DNA.

4. Both foreign RNA and DNA are present in transgenic animals.

Correct answer: 3) All cells of transgenic animals contain foreign DNA

Explanation:

Transgenic animals are genetically modified organisms that have had foreign genes introduced into their genome. These foreign genes are typically introduced through the integration of foreign DNA into the animal's cells. Therefore, option 3 stating that transgenic animals have foreign DNA in all their cells is the correct statement.

Hence, the correct answer is option 3) All cells of transgenic animals contain foreign DNA.

Q2. ANDi is a transgenic

1. Plant

2. Goat

3. Monkey

4. Dog

Correct answer: 3) Monkey

Explanation:

ANDi was the first genetically altered primate. The gene used was from a jellyfish, a fluorescent gene that was introduced into the embryo of a Rhesus monkey. It opened the doors for research in genetics and biotechnology as this achievement has tremendous potential for understanding genetic functions and the treatment of human diseases.

Hence, the correct answer is option 3) Monkey.

Q3. Maximum number of existing transgenic animals is of:

1. Pig

2. Fish

3. Mice

4. Cow

Correct answer: 3) Mice

Explanation:

Transgenic animals are animals that have modifications in the genome. Mice share similarities with humans. Mice are taken maximum for transgenic experiments. Transgenic animals are animals that have been genetically modified to contain foreign genes or alterations in their existing genes. Mice are commonly used in transgenic experiments due to their genetic similarities with humans, short life cycles, and ease of breeding. These animals are essential for studying human diseases, gene function, and drug testing.

Hence, the correct answer is option 3) Mice.

Also Read:

• MCQs on Transgenic Animals

• Bioremediation

• Microbes in Human Welfare

FAQs on Transgenic Animals

Q1. What are transgenic animals used for?

Transgenic animals are used in research, medicine (therapeutic protein production), agriculture (disease resistance), and conservation.

Q2. How are transgenic animals created?

They are created using methods like microinjection, viral vectors, electroporation, and lipofection to insert foreign genes.

Q3. What is transgenesis?

Transgenesis is the process of inserting foreign genes into an organism’s genome using recombinant DNA technology.

Q4. Are transgenic animals used in human disease research?

Yes, mice and other animals are genetically modified to model human diseases for studying mechanisms and drug testing.

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