Introduction
This reading summary essay focuses on the reading “Human Cloning – The Science and Ethics of Nuclear Transplantation” by Rudolf Jaenisch.
Summary
Jaenisch discusses ethical and scientific challenges associated with human cloning and the application of somatic-cell nuclear transfer to develop a child or ‘reproductive cloning’ (Jaenisch, 2004). He notes that there are numerous scientific findings to reject human cloning. This article shows that a cloned embryo can hardly develop into a normal human being. Jaenisch (2014) also examines the medical application of stem cells to manage numerous conditions.
Additionally, he looks at the variations between embryos developed by cloned processes against those derived by in vitro fertilization, noting that the first case has rare chances of developing into a normal being. Overall, no scientific remedies are currently available to correct problems associated with human cloning, while some challenges remain insurmountable.
Explanation
Apart from moral arguments against human cloning, scientific evidence also fails to support this technique (Jaenisch, 2004). A cloned embryo is observed to have extremely rare, if any, chance to develop normally. This is opposed to in vitro fertilization, which may develop, but with deficiencies. Jaenisch (2004) noted that cloned embryos elude the expected gametogenesis and fertilization processes and, thus, effective reprogramming of clone’s genome is not realized.
Hence, no normal organism should be expected. Jaenisch (2004) further showed that majorities of organisms developed through nuclear transfer often die in gestation period. Others that are born usually have numerous offspring syndromes, including metabolic and respiratory abnormalities, as well as dysfunctional placenta.
The epigenetic variation between chromosomes from father and mother (inherited) is the main biologic challenge to deriving normal human beings from cloning because one of the alleles would be inactive (from the sperm or oocyte) (Jaenisch, 2004). The nuclear transfer is followed by erasure because parental genomes are subjected to transformation or reprogramming once they enter the oocyte.
The author further notes that faulty reprogramming is common in reproductive cloning but not in treatment for two reasons. First, it happens because of the retention of the epigenetic memory of the donor nucleus at the blastocyst (Jaenisch, 2004). This precisely is responsible for the development into a normal or an abnormal and postnatal animal. Second, reproductive cloning needs the development of a fetus, which is not a requirement in the therapeutic application of nuclear transfer (Jaenisch, 2004). It only needs automatic identification of functional cells.
Overall, the article asserts that reproductive cloning is rejected nearly universally. However, the application of embryos obtained from nuclear cloning or in vitro fertilization to create embryonic stem cells is a contentious practice.
Evaluation
In 2013, scientists reported the first case of successful human cloning (Park, 2013). Mitalipov et al. reported that they had successfully “reprogrammed human skin cells back to their embryonic state” (as cited in Park, 2013, para. 1).
This new development in nuclear transfer shows that scientists may overcome some of the challenges identified by Jaenisch in his article. The success in the case of Mitalipov et al. was attributed to quality of the eggs (50%) and process optimization (50%), making this technique extremely efficient. Nonetheless, numerous challenges persist in human cloning. For instance, no study has demonstrated any outcomes when adult or mature cells are used, but scientists are eager to advance nuclear transfer techniques.
Conclusion
Human cloning raises both moral and technical challenges. While some achievements have been noted, these new techniques are yet to be tested for reliability and robustness. As such, previous challenges noted persist. Scientists will continue to advance their techniques to improve outcomes of human cloning.
References
Jaenisch, R. (2004). Human cloning – The science and ethics of nuclear transplantation. New England Journal of Medicine, 351(27), 2787-2791.
Park, A. (2013). Scientists report first success in cloning human stem cells. Time. Web.