Reproductive Cloning
In contrast to research cloning, cloning for reproductive purposes does not include the interruption of the development of an embryo after a short time. Instead, the embryo is transferred into the uterus of a hormonally prepared surrogate mother that will then carry the pregnancy to term similar to a normal pregnancy.
Since the birth of the cloned sheep Dolly in July 1996, various species have been cloned more or less successfully, like dogs, cats, rabbits, horses, cows and pigs. Aside from objectives of basic research, these cloning procedures also strive at practical aims like the breeding of livestock species that are resistant to specific diseases or that show otherwise desirable features.
In 2018, a method has been presented describing the first successful cloning of macaque monkeys. The method has been primarily developed for the use in biomedical research. However, it is also a possible step towards the reproductive cloning of humans. After the addition of specific enzymes to cell nuclei extracted from foetal tissue, two healthy monkeys resulted from six pregnancies. Experiments including the transfer of cell nuclei from monkey adult tissue did not result in viable, healthy offspring.
In most countries, attempts to clone humans are prohibited and – according to present knowledge – have not been realised yet.
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Liu, Zhen / Cai, Yijun / Wang, Yan / Nie, Yanhong / Zhang, Chenchen / Xu, Yuting / Zhang, Xiaotong / Lu, Yong / Wang, Zhanyang / Poo, Muming / Sun, Qiang (2018): Cloning of Macaque Monkeys by Somatic Cell Nuclear Transfer. In: Cell 172(4), 881-887. doi: 10.1016/j.cell.2018.01.020 Online Version