cloning

An illustration From T. MADHAVAN, M.Sc., M.L.I.S., M.Ed., M.Phil., P.G.D.C.A., Lecturer in Zoology..

Modern Genetics: Cloning

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GENE THERAPY



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CloningCloning is a technique of creating a copy of living matter - a cell or organism.

The copies produced through cloning have identical genetic makeup and are known as

clones

The term cloneclone (from the Greek word klōn, meaning “twig”) had already been in use since the beginning of the 20th century in reference to plants.

In 1963 J. B. S. Haldane [British biologist] use the word clone in reference to animals.



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Scientists initially made cloned cells in the laboratory by letting a single cell divide into a population of

genetically identical cells.

In this process scientists put the original cell in a laboratory dish containing culture medium.

The cell’s natural process of mitosis then produces genetically identical offspring.

This process mimics how cells multiply, for instance, in plants and in the human body

CLONING: a prelude



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Scientists later developed more complex cloning techniques

using animal embryos. Every cell in an animal arises from a fertilized egg. The fertilized egg divides to form an embryo, and each cell in the

embryo has the same genetic makeup.

At some point in the embryo’s growth and development, cells differentiate and become specialized.

For instance, a heart cell only functions in the heart and not the liver, even though the genes of a heart

cell and liver cell are the same.

CLONING: a prelude



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JOHN GURDON’s EXPERIMENTS

The experiment reveals that cells from different parts of the embryo differed in the degree of successful development on nuclear transplantation

The older the individual the nuclei were taken, less the recipient egg cells was able to develop normally.

Cells of embryos at a later stage of development switch over from totipotent to pluripotent state.



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CLONING method



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TOTIPOTENCY refers the ability of embryonic cell to give rise to all the different cell types in the body

PLURIPOTENCY refers the ability of embryonic cell to give rise the unique

cell types / tissues in the body



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CLONING: types

Reproductive cloning

Therapeutic cloning



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Cloning: therapeutic



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Cloning: reproductive

Cloning: therapeutic

Cloning of SheepCloning of Sheep [Mechanism]

Cloning of specific Cells /Tissues



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Cloning of Pine tree



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Merits of Cloning:

the endangered and extinct animals

can be saved or retained.

help to maintain biodiversity.

solves transplantation problems,

tissue incompatibility, tissue

rejection, harmful immune

reactions.

will produce advances in medicine,

biological research, and industry



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Demerits of Cloning:

Highly costlier,

More ethical issues.

Clones have discrepancies,

incompatibility, tissue rejection,

harmful immune reactions.

negative unwanted results may

occur due by crooked minded

people



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cloning

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