Complications: The Pros And Cons Of Human Cloning

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Strictly speaking, cloning is the creation of a genetic copy of a sequence of DNA or of the entire genome of an organism. In the latter sense, cloning occurs naturally in the birth of identical twins and other multiples. But cloning can also be done artificially in the laboratory via embryo twinning or splitting: an early embryo is split in vitro so that both parts, when transferred to a uterus, can develop into individual organisms genetically identical to each other. In the cloning debate, however, the term ‘cloning’ typically refers to a technique called somatic cell nuclear transfer (SCNT). SCNT involves transferring the nucleus of a somatic cell into an oocyte from which the nucleus and thus most of the DNA has been removed. (The mitochondrial DNA in the cytoplasm is still present). The manipulated oocyte is then treated with an electric current in order to stimulate …show more content…
Before Dolly, scientists thought that cell differentiation was irreversible: they believed that, once a cell has differentiated into a specialized body cell, such as a skin or liver cell, the process cannot be reversed. What Dolly demonstrated was that it is possible to take a differentiated cell, turn back its biological clock, and make the cell behave as though it was a recently fertilized egg.

Nuclear transfer can also be done using a donor cell from an embryo instead of from an organism after birth. Cloning mammals using embryonic cells has been successful since the mid-1980s (for a history of cloning, see Wilmut et al., 2001). Another technique to produce genetically identical offspring or clones is embryo twinning or embryo splitting, in which an early embryo is split in vitro so that both parts, when implanted in the uterus, can develop into individual organisms genetically identical to each other. This process occurs naturally with identical

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