UPSC Express

Sach-Gaurav

• It is born to a Murrah buffalo.
• Its birth weight is 54.2 kg and it has a normal physiological parameters and blood profile.
• The genotype of the calf was confirmed by microsatellite analysis (parentage verification) and chromosome analysis.

What is cloning?

• The term cloning describes a number of different processes that can be used to produce genetically identical copies of a biological entity.
• The copied material, which has the same genetic makeup as the original, is referred to as a clone.
• Researchers have cloned a wide range of biological materials, including genes, cells, tissues and entire organisms, such as a sheep, cow, etc.

Natural clones

• Clones can also occur naturally.
• In nature, some plants and single-celled organisms, such as bacteria, produce genetically identical offspring through a process called asexual reproduction.
• In asexual reproduction, a new individual is generated from a copy of a single cell from the parent organism.
• Natural clones, also known as identical twins, occur in humans and other mammals.
• These twins are produced when a fertilized egg splits, creating two or more embryos that carry almost identical DNA.
• Identical twins have nearly the same genetic makeup as each other, but they are genetically different from either parent.

Artificial clone

There are three different types of artificial cloning:

1. Gene cloning: It produces copies of genes or segments of DNA.
2. Reproductive cloning: It produces copies of whole animals.
3. Therapeutic cloning: It produces embryonic stem cells for experiments aimed at creating tissues to replace injured or diseased tissues.

Animal cloning

• In animal cloning, complete animal is produced from somatic cells of an animal.
• A somatic cell is any cell in the body other than sperm and egg, the two types of reproductive cells.

How are animals cloned?

• In reproductive cloning, researchers remove a mature somatic cell, such as a skin cell, from an animal that they wish to copy.
• They then transfer the DNA of the donor animal’s somatic cell into an egg cell, or oocyte, that has had its own DNA-containing nucleus removed.
• Researchers can add the DNA from the somatic cell to the empty egg by two different methods:
• In the first method, researchers remove the DNA-containing nucleus of the somatic cell with a needle and inject it into the empty egg.
• In the second method, researchers use an electrical current to fuse the entire somatic cell with the empty egg.
• In both processes, the egg is allowed to develop into an early-stage embryo in the test-tube and then is implanted into the womb of an adult female animal.
• Ultimately, the adult female gives birth to an animal that has the same genetic makeup as the animal that donated the somatic cell.
• This young animal is referred to as a clone.
• Reproductive cloning may require the use of a surrogate mother to allow the development of cloned embryo, as was the case for the most famous cloned organism, Dolly the sheep.

Benefit of animal cloning

• Animal cloning can be an excellent reproductive tool for conservation and multiplication of selected superior animals of buffalo breeds.