Cloning is the technique of generating organisms that are exact genetic duplicates of one another. Scientists’ major goal is to discover the “ultimate code” that produces a “perfect” organism – a body free of diseases and anomalies. Cloning, in this opinion, is beneficial in reducing the spread of fatal inherited disorders. Dolly the sheep was the first organism to be successfully cloned.
This case intrigued the psychologist in me, who wondered why some scientists are so eager to legalize this process when Dolly’s case was the 277th attempt. Thus, the unsuccessful 276th attempts have either failed to develop into a viable embryo or been aborted after they showed signs of abnormality. Such, high chances of failure with the accompanying issues of wastage of human embryonic material are not acceptable. However is it correct to think that cloning does not happen in the scientific community?
There are primarily two methods of cloning in which an embryo is formed other than by sperm fertilisation of an egg. Embryo splitting, also known as reproductive cloning, is a method of artificially stimulating the natural process of producing identical twins. This type of cloning was used in the production of Dolly. Somatic cell nuclear transfer or ‘therapeutic cloning’ is the only process capable of generating clones of living humans. It is a sort of non-reproductive cloning used to obtain stem cell lines for research. Stem cells are undifferentiated cells that can self-renew or develop into multiple cell types. Stem cells are classified into two types: multipotent stem cells (also known as “adult cell cells”) and pluripotent stem cells (also known as “embryonic stem cells”). The latter are derived from early embryos and have seen extensive study use.
The process of reproductive cloning is as follows: all genetic material carried by a single ovum (egg) is contained within a nucleus; if this nucleus is removed (ovum enucleation) and then replaced with the nucleus of a somatic cell (from the body of an embryo), an embryo genetically identical to the donor of the somatic cell nucleus can be created. The resultant embryo is subsequently implanted into a surrogate mother’s womb for gestation and delivery. The described approach has been applied in a process called ‘three-parenting IVF’. It enables women with mitochondrial disease to have a genetically related child free of the disease.
The mitochondrion has its own genome, the mtDNA, which encodes 13 proteins that are subunits of respiratory chain complexes. Mutations stop the mitochondria from converting food and oxygen into food, affecting negatively the heart, brain, and lungs. Dysfunctional mitochondria are implicated in several neurodegenerative diseases including Parkinson’s disease. Therefore, ‘three-parenting IVF’, or mitochondrial transfer in IVF could be considered an effective preventive strategy. However, it crosses ethical boundaries as it interferes with germ-line, not to forget the psychological and social implications.
Nevertheless, the CRISPR/Cas9 technology could be regarded as a better solution. It has grown in prominence due to its low cost and possible applicability in the treatment of genetic diseases. It is capable of strong gene editing. However, it may not affect all mtDNA, but it may change enough to lower the individual’s illness threshold, offering therapeutic benefits. This innovative technology could be utilised to treat diseased people as well as IVF embryos prior to implantation. It provides a reduction in mutation load, which lowers symptoms and disease burden. The CRISPR/ Cas9 editing of embryonic mtDNA may appeal as a more socially acceptable option to ‘three-parenting IVF’. Rather than merging the genetics of three people, it allows a couple to conceive without the need for donor genetic material.
The logic of human cloning and the logic of therapeutic cloning are identical; the spare embryo is created to expire. Nevertheless, a much better alternative could be the CRISPR / Cas9 gene editing technology, which attempts to cut off parts of defective DNA and subsequently reinstall it in the embryo. It can lead to reduced mtDNA disease, perhaps saving many affected people.
Reference list:
Brand, M.D. and Nicholls, D.G. (2011) Assessing mitochondrial dysfunction in cells, The Biochemical journal. U.S. National Library of Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/21726199/.
Gurnham , D. (2016) The mysteries of human dignity and the Brave New World of human cloning …, Sage Journals . Available at: https://journals.sagepub.com/doi/abs/10.1177/0964663905051219.
How CRISPR let you edit DNA (2019) YouTube. YouTube. Available at: https://www.youtube.com/watch?v=6tw_JVz_IEc.
José , V.D. (2008) Cloning humans, cloning literature: Genetics and the imagination deficit, New genetics and society. U.S. National Library of Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/17256208/.
O’Mathúna, D.P. (2002) What to call human cloning – EMBO press, Viewpoint. Available at: https://www.embopress.org/doi/full/10.1093/embo-reports/kvf122.
Rulli , T. (2016) What is the value of three-parent IVF?, The Hastings Center report. U.S. National Library of Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/27198755/.
This is a fair blog where you have done a very good job of explaining how cloning – both reproductive and therapeutic – works. You go into an appropriate level of detail, which demonstrates a good understanding of your subject value.
Although you very briefly provide context of your background reflectively, you could improve by reflecting on what you haev learned throughout. Clearer references to your sources, by hyperlink, and critical analysis to compare or reflect on them would also help improve.
On a minor point – not all pluripotent stem cells are embryonic….