CLONING

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Cloning allows to generate population of genetically identical molecules, cells, plants or animals. Because this technology can be used to produce molecules, cells, plants and some animals, its applications are exceptionally broad.
 
TYPES OF CLONING
1. Molecular or Gene Cloning:- Molecular or gene cloning, the process of creating genetically identical DNA molecules, provides the foundation of the molecular biology revolution and is a fundamental and essential tool of biotechnology research, development and commercialization.
 
2. Animal Cloning :- Animal cloning helps to rapidly incorporate improvements into livestock herds.

Methods of Cloning

i) Artificial Embryo Twining (AET)

  • In AET, the natural process of creating identical twin is mimicked, but in a lab instead of the mother’s womb. Scientists naturally separate a very early embryo into individual cells and then allow each cell to divide and develop on its own. The resulting embryos are placed into a surrogate mother, where they are carried to term and delivered. Since all the embryos come from the same zygote, they are genetically identical.

ii) Somatic Cell Nuclear Transfer (SCNT)

  • SCNT involves the isolation of a somatic (body) cell, which is any cell other than those used for reproduction (sperm and egg, known as the germ cells). In mammals, every somatic cell has two complete sets of chromosomes, whereas the germ cells have only one complete set. To make Dolly,(the first cloned Ship) scientists extracted the nucleus of a somatic cell taken from an adult female sheep and transferred it to an egg cell from which the nucleus had been removed. After some chemical manipulation, the egg cell, with the new nucleus behaved like a freshly fertilized zygote. It developed into an embryo, which was implanted into a surrogate mother and carried to term giving birth to Dolly.
Controversies over Animal Cloning
  • There are considerable technical issues and risks involved in the technique. (Note: Dolly died at the age of six while a sheep usually lives for 10 to 16 years. Also, Dolly had a fast rate of ageing.)
  • No matter how many species are cloned human cloning will always be an experiment as different species have different behavior towards cloning i.e. even if we solve the problem with the ape or monkey cloning, cloning of humans will still be full of problems.
  • Another problem is the relatively low rate of success in cloning and the fact that many of the cloned animals are born with deformities or congenital defects.
  • Cloning of human babies is certainly likely to become feasible but many regard this as both dangerous and morally wrong.
  • Using the cloning and genetic engineering, it is possible to change the genetic makeup of the embryo, giving rise to the possibility of the “designer baby”. Some people see nothing wrong in it. They say it is good rather than spending huge sum of money on schools. But it is also true that such technology would be available to only few wealthy people.
  • Considering the “Designer Baby” scenario, it is also important to remember that no technology is ever precisely predictable, and our current understanding of genetic engineering is very limited.
  • Religious groups have also raised serious objections as it is against the basic religious principles.
Practice Questions
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