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| Cloning of Organisms |
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| Two or more individuals with identical genetic make up formed from one parent by asexual reproduction are called clones. For example, daughter plants produced by strawberry runners and whole plants produced by tissue culture are clones. Similarly, the individuals formed by budding on the same parent Hydra are also a clone. |
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| The identical twins (also called monozygotic, or one-egg twins) develop from one egg by splitting of the early embryo. They contain identical genetic information and usually of very similar appearance. Thus, they are an example of a clone, and are always of the same sex. Any physical or mental difference notable between identical twins arises from environmental influence before and after birth. |
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| The Armadillo, Dasypus novemcinctus, always produces a clone of four identical young ones of the same sex at a time formed form a single zygote. |
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| This natural phenomenon is called polyembryony. |
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| fig. 25.8 Worlds first cloned cat called “CC” (Calico Cat) seen with her surrogate mother Allie |
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| Ian Wilmut and co-workers produced in 1997, the worlds first clone of an adult sheep at Edinburgh's Roslin institute. The clone of a sheep was created from a single cell taken from the udder of an adult sheep. This cell was turned into an embryo and transplanted into a surrogate mother. |
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| Subsequently, there have been several such attempts to create clones of many other organisms including humans. |
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| The cell or organisimal cloning is aimed at preserving the genotype of a cell or organism. It counteracts death in a way, in which there is a loss of the cells or organisms of a specific genotype. |
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