China
Africa
Explore chapters and articles related to this topic
Exploitation and control of women's reproductive bodies
Published in Wendy A. Rogers, Jackie Leach Scully, Stacy M. Carter, Vikki A. Entwistle, Catherine Mills, The Routledge Handbook of Feminist Bioethics, 2022
Therapeutic cloning involves producing stem cells which can repair and replace damaged human tissue, and it depends on a suitable supply of human eggs. Biologists have observed that the mammalian egg can remodel and replicate chromosomes not only from a sperm head but also from a variety of other cells (Kiessling 2004). This property has been exploited in the process of somatic cell nuclear transfer (SCNT), which involves removing the nucleus from an egg and replacing it with the nucleus of a somatic cell. The egg is then stimulated with a shock to develop into an embryo, either for transfer to a uterus for further development (reproductive cloning), or for culture in vitro (therapeutic cloning).
Reproduction
Published in Gary Chan Kok Yew, Health Law and Medical Ethics in Singapore, 2020
Cloning is the reproduction of genetic material of an ancestor-organism without sex.116 The process is known as somatic cell nuclear transfer where the nucleus of an adult cell is taken from an existing organism and implanted or fused into the egg. The egg still contributes the mitochondrial DNA albeit not a significant amount of genetic material. Nonetheless, the clone would still be genetically different from the ancestor.
Amazing ambitions
Published in Brendan Curran, A Terrible Beauty is Born, 2020
Researchers are now investigating the possibility of applying more extensive genetic manipulation to tissue cultured cells prior to using them in nuclear transfer. The objective is to re-programme animal development so that their organs lack the biological molecules making those organs unsuitable for transplantation into humans. Likewise, they wish to introduce multiple genes to produce large changes in the genetic programmes of the recipients. The speed with which animal cloning and animal re-programming have been thrust upon the scientific community has been nothing short of stunning, ensuring that the application of nuclear transfer technology to human cells is now firmly on the scientific agenda.
Human Germline Genome Editing: On the Nature of Our Reasons to Genome Edit
Published in The American Journal of Bioethics, 2022
For the moment, neither artificial gametogenesis nor live birth after nuclear transfer has yet been demonstrated in humans. However, as noted above, artificial gametogenesis has been achieved in mice and is widely expected to eventually be possible in humans. Nuclear transfer is already used to produce genetically modified non-human animals and related procedures are employed in human cells in the context of mitochondrial replacement techniques (Craven et al. 2010). It is therefore not unreasonable to expect these technologies to be developed in the not-too-distant future. It is true that both of these technologies would raise a host of other ethical issues should they ever come to fruition. Nuclear transfer, in particular, is likely to be highly controversial insofar as it would make it possible to clone existing—or deceased—human beings. Nevertheless, the potential of these technologies to facilitate genome editing is itself likely to be an important consideration in the case for developing them.
Challenges and ethical considerations for using cloned primates for human brain discovery
Published in Expert Opinion on Drug Discovery, 2018
Alan O. Trounson, Andrew J. French
Ethical discussion on cloning has mainly been confined to human reproductive cloning and somatic cell nuclear transfer or therapeutic cloning [15]. There were some concerns about cloning farm animals and their entry into the human food chain but these have disappeared with regulatory approval for their use. Cloning NHP is a technical step closer to the cloning of humans and this might be an ethical concern to some people. Regulatory authorities do not require data from NHP models in preclinical medical research unless the therapeutic risks and efficacy cannot be demonstrated adequately in rodents or other large animals, or in vitro. It is difficult to completely avoid the use of NHP in neurological research because of the need to find models that represent closely human neuronal conditions. NHP research attracts increased opposition from animal activists but the degree of concern varies in different cultures. There is also a general trend by research ethics committees for reducing the number of animals used in experiments in medical research and cloned animals may be considered as supporting this trend because of their genetic homogeneity. However, other practical factors such as cost and availability will also impact on the use of cloned NHP.
Treating donor cells with 2-PCPA corrects aberrant histone H3K4 dimethylation and improves cloned goat embryo development
Published in Systems Biology in Reproductive Medicine, 2018
Tingchao Mao, Chengquan Han, Ruizhi Deng, Biao Wei, Peng Meng, Yan Luo, Yong Zhang
The nuclear transfer was performed on the basis of a previous study (Liu et al. 2011). The first polar body and a small amount of adjacent cytoplasm were removed with a 25 µm diameter pipette. Enucleated oocytes were then checked for the absence of chromosomes under ultraviolet radiation. Subsequently, a round donor cell was injected into the perivitelline space of an oocyte. Later, the couplets were placed between two copper electrodes and then fused by pulse at 32 V for 20 s with an interval of 1 ms. The reconstructed embryos were incubated for 2–3 h in TCM-199 supplemented with 7.5 μg/mL cytochalasin B and 10% FBS. Finally, they were activated in 5 μM ionomycin for 5 min and then 2 mM 6-dimethylaminopurine for 4 h. After extensive washing, the presumptive embryos were cultured in 200 μL mSOF covered with mineral oil.