Cloning is defined as “the technique of producing an exact genetic copy of an organism, tissue, cell or gene by replacing the nucleus (a membrane-bound structure that contains a cell’s hereditary information and controls its growth and reproduction) of an unfertilised ovum with the nucleus of a body cell from the organism”.
Human cloning therefore is the creation of a genetically identical human by replacing the nucleus of an unfertilized ovum with the nucleus of a body cell (for example a skin cell) from the human intending to be cloned. The term is generally used to refer to artificial human cloning, which is the scientific reproduction of human cells and tissue.
History of Cloning
Human Cloning has been a hot topic for debate and research since the 1960s, but much progress was not seen until the cloning of a sheep known as Dolly in 1996/1997 by somatic cell nuclear transfer (SCNT). The cloned sheep, Dolly was exactly similar to the naturally conceived sheep. The only difference between the two was that Dolly’s embryo was developed without the presence of sperm.
After the success of Dolly, the idea of human cloning became an interesting scientifical adventure for scientists. Although many nations outlawed it, a few scientists embarked on a mission to clone a human being and promised to make a clone within the next few years. The first hybrid human clone was created in November 1998, through Advance Cell Technology. It was created using somatic cell nuclear transfer (SCNT) where a nucleus was taken from a man’s leg cell and inserted into a cow’s egg from which the nucleus had been removed, and the hybrid cell was cultured and developed into an embryo. Unfortunately, the embryo was destroyed after 12 days.
Again, in January 2008, the first five mature human embryos using SCNT were successfully created and announced by Dr Andrew French and Samuel Wood of the biotechnology company Stemagen. In this case, each embryo was created by taking a nucleus from a skin cell donated by Mr Wood and a colleague and inserting it into an enucleated egg. The embryos were developed only to the blastocyst (a fertilized egg that has developed for 5-6 days) stage, at which point they were studied in processes that ended up destroying them.
Then in 2018, two live female clones, crab-eating macaques (a species of monkey native to Southeast Asia) named Zhong Zhong and Hua Hua were born. They were the first successful cloning of primates using SCNT.
Types of Human Cloning
The how and why of cloning depends on what is being cloned. There are three main types of human cloning, they are; gene cloning, reproductive cloning and therapeutic cloning, although the commonly discussed types are therapeutic cloning and reproductive cloning.
Gene cloning is a biochemical reaction that takes place in every single cell in every organism. It’s the creation of a copy of genetic material from an existing strand of genetic material.
Sometimes called molecular cloning, it is the procedure of isolating DNA sequence that is of interest to make several replicas. Gene cloning simply means duplicating an existing genetic material.
This natural reaction can be recreated in the lab and is an essential tool for many aspects of biological research. It is the most commonly applied type of cloning, and the process has been ongoing for over 30 to 40 years with the cloning of animals.
And perhaps the most medically applicable type of cloning for humans is therapeutic cloning, which creates cloned embryonic stem cells of a patient to create genetically identical cells that can treat a medical condition.
The main aim of therapeutic cloning is to grow or develop stem cells (essential cells that replace damaged cells or cells lost due to diseases) from the cloned embryos which would help in treating many diseases/disorders. It also assists in organ replacement therapy. The procedure involved is similar to that of SCNT, but instead of inserting the embryo into a surrogate mother, its cells are used to grow stem cells. These stem cells are used for the respective therapies.
Therapeutic cloning would involve cloning cells from a human for use in medicine and transplants. It is an active area of research but is not in medical practice anywhere in the world yet. Two common methods of therapeutic cloning that are being researched are somatic-cell nuclear transfer and more recently pluripotent stem cell induction.
Perhaps the most commonly discussed and debated type of cloning is reproductive cloning. Reproductive cloning is done to duplicate a human to his/her offspring which exactly resembles his/her parent.
Reproductive cloning makes use of the somatic cell nuclear transfer (SCNT) technique to develop the embryo. This technique involves the donation of an egg cell with a nucleus from the female donor. The nucleus of the egg cell is removed creating an enucleated egg (an egg that has had its nucleus removed). The person who is being cloned acts as a somatic cell donor. The somatic cell should contain DNA as its genetic material. The somatic cell (cells that make up an organism’s body and are not used to directly form a new organism during reproduction) is fused with the enucleated egg in an artificial medium using electricity. The high voltage makes pores in the somatic cell membrane and facilitates the infusion of egg cells into the somatic cell. This results in the formation of an embryo.
The embryo is then implanted into the surrogate mother’s uterus for gestation. At the end of the gestation period, the surrogate mother gives birth to the cloned baby of the cloned subject. But, usually, the success rate for this procedure is very low and only one or two out of 1000 embryos would reach the world.
Reproductive cloning would involve making an entire cloned human, instead of just specific cells or tissues, it involves creating genetic duplicates of whole organisms from the genetic material of an already-existing organism. The cloned organism is very similar to being an identical twin to the parent organism, just that it is born later.
Despite the possibilities and advantages that human cloning could provide, the challenges and concerns weigh heavier, for instance, gene modification which involves implementing enzymes from bacteria to locate genes within our DNA to create the desired modification for duplication, might allow us to create a perfect DNA free from diseases and abnormalities, but in doing this we just might eradicate the diversity within our genome which makes us who we are. Cloning can only replicate the human body (the flesh) and not the soul which makes us human.
Yes, cloning might bring about great achievements in medicine that are geared towards preserving humanity but, it might also always be an imperfect science, and since it involves having enough viable embryos available for scientists to use, women will end up being exploited as they would have to receive medication injections that would help them ovulate rapidly and this process involves side effects that lead to abdominal pain, reproductive health concerns and infertility in rare cases.
Just like those scientific movies on cloning, the social strata will be imbalanced, the wealthy and powerful will have more and easy access to the program while the rest end up as potential commodities. It never ends well.
Human cloning is just man’s quest at playing God and we might have another “Tower of Babel” situation with this. The possibilities of human cloning have raised controversies, that are majorly spiritual and ethical concerns which has prompted several nations around the world to pass laws banning human cloning.
So, what is your take on Human cloning, is it the “holy grail” of human civilization or humanity’s eventual doomsday?