First, let's get some general information about cloning. Cloning is called various methods used to produce copies of biological entities with exactly the same genetic structure. The copied structure is called a clone. Although cloning often seems to happen artificially, identical twins are actually a kind of natural clone. Twins have almost the same genetic makeup as each other and differ from their parents.
If we look at artificial cloning, we see that there are three different methods. Gene cloning, reproductive cloning, and therapeutic cloning. In gene cloning, a copy of genes or DNA segments is produced. In reproductive cloning, a somatic cell is removed from an animal and placed in an egg cell that has had its nucleus removed and transferred to the surrogate animal so that an animal with the same genetic material is born and a copy of the whole animal is created (Dolly is one of the most famous examples of this type of cloning). In therapeutic cloning, embryonic stem cells are produced to be used in the production of new cells or to replace damaged tissues. These stem cells can be used in experiments to understand diseases and develop new treatments.
Cloning techniques are often used to make a copy of the genes to be studied. The gene taken from an organism is transferred to the genetic material of the carrier and the carriers are reproduced in the laboratory, thus creating many copies of the gene. Examples of these carriers are bacteria, fungal cells, viruses, or plasmids.
Many animal cloning experiments have been carried out so far. One of these is the first clone mouse produced by transplanting a mouse embryo separated in a test tube into a carrier in 1979. Later, cow, sheep, and chicken clones were produced by similar methods. In 1996, after 276 trials, Scottish researchers cloned Dolly from the cell of a 6-year-old sheep. Two years later, Japanese researchers cloned eight calves from a cow, but only four of these clones survived. In addition to these, there are animals such as cats, deer, dogs, horses, and rabbits among the cloned animals.
So, among all these experiments, have any humans ever been cloned?
In 1998, scientists from South Korea cloned human embryos, but the experiment was terminated early on. In 2002, a cloning organization called Clonaid announced the news of a girl named Eve who was claimed to be the first human clone. However, no evidence was presented to confirm this clone or the other 12 alleged human clones. In 2004, a research group led by Woo-Suk Hwang at Seoul National University in South Korea published an article in the journal Science about cloning a human embryo in a test tube, but it was withdrawn in 2006 because of an independent scientific committee found no evidence to support this claim. So, as you can see, we do not have a successful result yet.
Technically speaking, humans or other primates are more difficult to clone than other animals. One of the reasons for this is that the two proteins necessary for cell division are located very close to the chromosomes in the primate egg. For this reason, removing the nucleus of the egg causes the removal of these necessary proteins and inhibits cell division. In other mammals such as cats, rabbits, and mice, these two proteins are scattered throughout the egg. For this reason, removing the egg core does not cause protein loss. In addition, some dyes used to remove the egg nucleus and ultraviolet light can damage the primate cell and prevent its growth.
So, what could be the uses of animal cloning?
Scottish researchers who cloned Dolly cloned another genetically modified sheep that produces milk that contains a human protein effective in blood clotting. The aim here is to one day separate this protein from milk and give it to people with blood clotting problems.
Another possible use for cloned animals is testing new drugs and treatments. One of the biggest advantages of using clone animals is that they all have the same genetic makeup, which means that their response to drugs will be the same, not variable as in different animals.
After consulting many scientists and experts, the FDA decided in January 2008 that the meat and milk of cloned animals were as safe as the original animals. The FDA's approach shows that researchers can use cloning to replicate animals in the agricultural field. However, since the cost of cloning is high, it seems that it will take many years for the products obtained from cloned animals to appear in the markets.
Another area of use is to create a population of endangered or extinct animals. In 2001, researchers cloned for the first time an endangered Asian aurochs called the Gaur. Unfortunately, the calf Gaur, which developed inside a surrogate mother cow, died a day or two after birth. In 2003, another endangered cattle Banteng was successfully cloned. Shortly thereafter, three African wildcats were cloned using frozen embryos as the DNA source. While some experts think that cloning can save many extinct species, others oppose the idea of producing identical individuals without the genetic diversity necessary for life.
An embryonic stem cell, which has the ability to create almost any cell produced by therapeutic cloning, is intended to be used in the laboratory to create healthy cells and replace damaged diseased ones.
As you can see, animal cloning has many potential uses and advantages. Well, are there any downsides?
As you can see in the examples we gave before, the number of clones that have survived many cloning attempts is very few. Dolly, for example, was the only surviving clone out of a total of 277 clone embryos. This rather low yield, combined with a concern for trust, creates a serious obstacle to the implementation of cloning.
Some side effects observed in cloned animals are disadvantageous in terms of cloning. These side effects include large birth sizes, damage to vital organs such as the liver, brain, and heart, premature aging, and immune system problems.
Another important issue is the average age of the cell chromosomes of the clone. As the cell goes through the normal division process, the telomeres at the ends of the chromosomes shorten. Over time, the telomeres shorten until the cell can no longer divide, and then the cell dies. This event is part of the natural aging process that takes place in all cells. As a result, clones produced from a cell from an adult already have shortened chromosomes, which can lead to a shorter lifespan of the clone cells. Indeed, Dolly, cloned from a 6-year-old sheep, lived half the life of an average sheep, which is normally 12 years.
The similarity between the stem cell, which is intended to be produced in therapeutic cloning, and the cancer cell, raises concerns. Both cell types can multiply uncontrollably, and some studies show that after 60 cell division cycles, the stem cell can cause the accumulation of cancer-causing mutations. Therefore, before deciding whether to use stem cells in the treatment of diseases, the relationship between stem cells and cancer cells should be understood more clearly.
Ethical issues with cloning
Reproductive cloning has the potential to genetically replicate a previously existing or still an existing human being. Therefore, it causes long discussions in terms of religious and social values, as it violates individual freedom and identity.
In therapeutic cloning, it is suggested that it can be used in the treatment of sick or injured people while causing damage to the embryo in the test tube. Therefore, opponents argue that collecting embryos to use this technique, no matter how helpful it may be to patients, is wrong.
Will the copied individual be the same as the original?
Let's say we found a way to circumvent all the negatives, disadvantages, and ethical concerns and we succeeded in cloning a human. Who exactly is this clone? Can we say that it is exactly the same as the original or does it become a completely different and new individual with the visual of the original?
As you know, the environment and our upbringing have a great influence on the formation of our personality. Therefore, when we clone ourselves, the factors in character development will be completely different, as our clone will grow up in a completely different environment from our own from the very beginning. It doesn't sound right to expect a clone to have the same personality traits, while even identical twins don't have the same character.
How much influence do the duplicated genes have on the character of the clone? How much of our personality depends on our genes?
Yes, the influence of the environment on our personality is undeniable. However, we should not ignore the role of genes in the formation of our identity. Let me give an example of the effect of genes on the character from an experiment on twins. A study is conducted on 350 twins raised together or separately, and it is seen that identical twins have similar characteristics regardless of their raising environment. The results of the study show that identical twins share 50% similar characteristics, while fraternal twins share only 20%.
Let me give another example of an experiment on the influence of genes on our character and behavior. Researchers from Emory University School of Medicine created conditioning in experimental mice for the smell of cherry blossom. The rats were given electric shocks each time along with the scent. It was observed that subsequent generations of mice that developed the conditioning had a fear of that same smell, even though they were not exposed to electric shocks. These findings became more certain with the finding of the same fear in later generations, even in individuals resulting from artificial insemination. If this is true for humans, it means that the traumas or fears experienced by our previous generation may also affect our view of the world.
Long story short, although the clone does not have the same growth environment and experiences as the original, it may carry some character traits from its copied genes.
We talked about the effects of the environment on our character. Our experiences are recorded in our brain and can guide us in determining our next move. So would combine all these factors, genes, and memories offer us the opportunity to completely replicate an individual's character? For this, I guess we should be able to copy a whole brain or transfer all the information and memories in the brain to some kind of computer. So, is it possible to copy a brain?
Scientists are currently able to generate neurons or other types of brain cells, but they are yet to derive a functional mixture from these cells. Let's say they do it one day and clone the whole thing into a whole brain. Can this clone brain have thoughts without being attached to a body? Or can we see the clone brain as an individual?
Many researchers argue that a lab-generated clone brain will never become an individual. However, it is difficult to pinpoint consciousness precisely. Nita Farahany of Duke University says we can detect the state of unconsciousness, but it is difficult to tell whether other species have consciousness or which have the capacity to develop consciousness.
But what if we could transplant the clone brain into a body? Or what if we found a way to communicate with him via a computer to find out if he's conscious? Can we make it develop memories if we connect it to external sensors so that it can detect what's going on around it? Unfortunately, we do not know to answer these questions for now.
In the event of complete brain cloning in the future, what we need is all the personality traits of the individual to be cloned, namely the memories, that is, the whole of the information that has taken place in his brain. Therefore, we need to transfer the information in the brain of the original individual to the computer and then transfer this information to the copied brain. Here, of course, new questions come to my mind. Is it possible to transfer the information in the brain to the computer? Can a computer and storage area be developed to handle this much information? Can the stored information be transferred to another brain? Or can information be transferred from brain to brain?
So let's take a look at the mind-loading process. Mind uploading is a hypothetical concept of generating a copy of the human's inner world and transferring it to the computer. The human brain, which consists of 80-100 billion neurons making billions of connections per second, is the most complex biological structure known. When it comes to such a complex structure, it is just as difficult to create a similar one in the digital world. For this, we need to make a detailed map of the brain.
A connectome is a kind of catalog of structures in the brain, how they connect, and how they interact with each other. A connectome contains brain structures that are both interconnected and independent yet working together.
The Human Connectome Project, which consists of many academies and research institutions in 2014, is working on mapping the connectome. In 2016 they published the most detailed map of the cerebral cortex to date.
Although research on the human brain is still in its infancy, scientists have had good results with fewer complex creatures. In 2012, a nematode (roundworm) connectome with 302 neurons and 7000 connections was successfully mapped. To do this with a human brain containing 100 billion neurons, it seems like a big leap forward in brain scanning technology is needed for now.
Let's say we've managed to map 100 billion neurons in the human brain, and our next step is to develop a computer model that can simulate this. Advances in artificial intelligence give us great hope that this can be achieved. According to the researchers, in the future artificial neural networks will be able to completely mimic their biological counterparts.
The main obstacle in front of this goal is that the computing power and storage areas of the computers we have are not sufficient yet. Although artificial neural networks already serve many purposes such as running our search engines, digital assistants, and driverless cars, an artificial network equivalent to 86 billion has not been established yet. However, developing computer technology may soon make it possible to control such large data sets.
Suppose we have recorded the information in the computer, and now it is time to transfer them to another brain. One of the most important issues we need to know before that is neuroplasticity, the ability of the brain to change physiologically. Every new knowledge learned or every new experience gained creates changes in certain regions of the brain. If we can detect these changes and make changes in the structure of the target brain, we may theoretically have the same knowledge or skill. In fact, it may even be possible to transfer information directly from brain to brain using this technique. In fact, to exaggerate a little more… What could prevent us from using a lab-generated brain as a storage space? Thus, until the next clone is developed, we would not have to complain about the limited and insufficient storage areas in the brain of the individual to store information.
And finally, if we can transfer even information from a cloned brain to a clone body, or if we can directly include mind loading in the development process of the clone body, it does not seem that impossible to obtain the same individuals. Imagine if such a process could be completed without any problems. We could solve many problems, from diseases such as Alzheimer's and Parkinson's, which occur due to brain damage, to health problems such as paralysis, where the body can no longer be used. If we kept cloning ourselves in this way countless times at regular intervals, we could live a long life, if anyone wanted to live that long.
Could we live as if reborn in a new undamaged body with a fresh brain but as an individual with the same memories and inner world? At this point, it is worth remembering that although most identical twins grew up in the same environment, they have different characters. In other words, even if we succeed in copying each of our cells, our consciousness may not suddenly awaken in that new body. The human brain and consciousness are still a great puzzle to be solved...
To what extent do you think a clone can replicate? How possible is it to make an identical clone? In your opinion, what kind of way can be followed to perform one-to-one copying? And if it were possible would you want to clone yourself? I would be very happy if you share your ideas with me.
Resources
https://www.buzzworthy.com/memories-dna-grandparents/
https://www.genome.gov/about-genomics/fact-sheets/Cloning-Fact-Sheet
https://medium.com/predict/can-we-upload-human-consciousness-85123b0b780f
https://www.popsci.com/grow-brain-in-lab-person-conscious/
https://www.verywellmind.com/are-personality-traits-caused-by-genes-or-environment-4120707
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