The idea that an individual could be identically replicated has captivated popular culture for decades. A clone is defined in biology as an organism or cell, produced asexually from one ancestor, to which they are genetically identical. Appearing in the likes of the Star Wars franchise, Oblivion, and more recently Mickey-17 released just this month, clones in science fiction films are often portrayed in a way that challenges this definition. When reproductive cloning and Dolly the sheep were introduced in Nick Evans’ lecture on stem cells, I asked myself the following questions:
- To what extent does cloning exist?
- Why haven’t we cloned humans?
- What are the applications of cloning?
Animal cloning – Dolly the sheep
On the 5th of July, 1996, the first mammal cloned from an adult somatic cell was born – Dolly the Finn-Dorset sheep. The scientific advancement captured the attention of the media at the time, and continues to do so today (see links on right). The procedure involved somatic cell nuclear transfer, which is a type of reproductive cloning. The diagram below summarises the method.
Dolly essentially had three mothers, with the DNA from the egg cell of a Scottish Blackface sheep being replaced by the DNA from a Finn-Dorset sheep. The resulting hybrid cells were placed in the uterus of another Scottish Blackface, and astonishingly, Dolly was born with identical genes to the nucleus donor sheep. In theory, the exact same procedure could be completed with humans. It should be noted that it took 227 attempts to produce one sheep clone. Even today, mammalian cloning is highly inefficient.
Ethical Considerations
Following the birth of Dolly, the United Nations Educational, Scientific, and Cultural Organisation (UNESCO) immediately banned cloning. It goes without saying that cloning humans would raise innumerable ethical issues. Below are the most notable (click on the arrows for more information):
Eugenics
An early ethical consideration, following John Lederberg advocating for cloning in 1966. He saw it as an appropriate means to improve the human race – cloning certain individuals for their desirable traits. Many see this is a ‘new form of eugenics’, which is considered immoral by most, due to questions of equality and coercion.
Danger
Utilitarianism focuses on the direct outcome, raising the concern that cloning human beings by nuclear transfer is too dangerous. Too many embryos in animal cloning experiments expire or result in miscarriage.
Individuality
Many believe that cloning violates our dignity, uses people as means, affronts our uniqueness, and threatens our humanity.
Embryonic research
To even research human cloning, a huge amount of human donated eggs would have to be acquired by scientists. The nature of the nuclear transfer method, with implantation would also require the research to surpass the 14-day limit of embryo experimentation, raising questions on identity and the value of human life.
Therapeutic Cloning
Therapeutic cloning is a practical method which in my opinion avoids the ethical issues raised above. It also involves nuclear transfer, but the cells are never implanted. Instead, the embryo is cloned to produce stem cells. Since these would be genetically identical to the donor, these stem cells are less likely to be rejected by the patient.
Conclusion
It seems to me that human cloning is inefficient, immoral, and mostly pointless. The replicas we see in science fiction don’t reflect biology, and with therapeutic cloning, there is no need to clone entire humans for treatment.
“Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should.”
Ian Malcolm, Jurassic Park (1993)
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