Cloning

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uppladdat: 2003-12-07
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2. Summary
In this project you will take a dive into the world of cloning. Cloning might be a hard subject to understand, but after reading this project you will get a better grip on the topic and be able to take better part in diskussions. You will in this project read about what cloning is, the history, the risks with cloning, cloning of humans, and more.


3. List of contents
Introductions and aims 4
Backgrounds 4
Aims 4
Material and methods 4
Material 4
Methods 4
Cloning 5
What is cloning? 5
Cloning history 6
Is a clone an exact copy of the original organism? 8
The risks of cloning 8
Can humans be cloned? 9
Pro and con human cloning 10
Conclusions 13
References 14




4. Introduction and aims
4.1 Backgrounds
I chose to write about cloning because it is a very current topic, and I wanted to take a closer look at it. The clones that are showed in movies and tv-shows are not exactly realistic, I wanted to find out how similar a clone actually is to its “original” and how it really works.

4.2 Aims
The aims with this project was in the first place to get a better understanding about cloning, to be able to take better part in diskussions for example. But another aim is to spread information and contribute to better understanding of cloning in general.

6. Material and methods
6.1 Material
This project is based on facts from the Internet only. I chose not to use any books or information booklets because I got the impression that there was plenty of good, reliable information to get on the Internet. I also worked with this project in many different places, so it was easier not having to carry around heavy books whenever I needed to change studyplace.

6.2 Methods
I had some problems of deciding what I was going to write about, so I have to admit that it took a while to figure that out. After deciding a topic everything went pretty good. I started searching for facts on the Internet and found lots of information. I read the material I found and then started writing on the computer, not using any handwritten drafts. The hard part was to read about cloning on english, with all the medical terms about cell-division and so forth, and using footnotes everywhere in the text was also a little confusing in the beginning.
7. Cloning
7.1 What is cloning?
The defenition of cloning is the making of an organism that is an exact copy of another, which means that the cloned/copied organism will have the exact same DNA-set as the original organism. There are different ways of creating a clone, one way which is older and more “low-tech” and one newer. The older way is called artificial embryo twinning, and is very similar to natures way of creating twins (which in a way are clones because of their exact same DNA-set). Natures way of making twins is when a fertilized egg tries to divide itself into an embryo with two cells. The two cells continue to devide themselfs and grow on their own, and turn into two seperate individuals with the exact same genetical information.1 Artificial embryo twinning mimics this natural process, but the difference is that it occurs in a Petri dish and not in the mothers body. The fertilized egg is also manually seperated into two cells, which then are able to divide themselfs and grow on their own. The embryos are placed into a surrogate mother, who carries them and eventually gives birth to them. The result is two genetically identical individuals, just as in the natural process of the creating of twins.2
The other, newer method of creating clones is called somatic cell nuclear transfer (SCNT). It was this method that was used when Dolly the Sheep was created (the first succesfully cloned mammal). The first step in the SCNT-method is to isolate a somatic cell from an adult animal. This cell has something called a nucleus which contains the animals DNA. The nucleus from the cell is transferred and put into an egg-cell from another animal where the nucleus has been removed.3 To be able to stimulate cell division the reconstructed egg has to
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1 http://gslc.genetics.utah.edu/units/cloning/
2 Ibid
3 Ibid


be given certain chemicals or electric current. This is done in a laboratory where the egg now is supposed to start dividing itself just like a naturally fertilized egg. When it has become 8 or 6 parts the cloned embryo is transferred into the uterus of a female host where it is supposed to develope until birth. The female host should be a female animal of the same species, or at least somewhat near the kind of animal that the DNA was taken from in the beginning.4

7.2 Cloning history
The first time artificial embryo twinning was used was in 1885 when a scientist named Hans Adolf Edward Dreisch managed to seperate the cells from a two-celled embryo of a sea urchin. Each cell was able to seperatly grow into clomplete sea urchins. The next step was to try the same thing on a more complex organism, for example an organism with a real backbone. Scientist Hans Spemann was the one who took the whole thing to the next level. He was able to succesfully seperate an embryo from a salamander, and also this time the two cells grew into two “twin-salamanders”. This happened year 1902. Hans Spemann also showed in 1928 that it is the nucleus in a cell that carries all genetic information. With this knowledge he found out that a nucleus in a fertilized egg cell
the cloning technology called somatic cell nuclear transfer. In the year of 1952 two scientists
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4 http://www.ornl.gov/TechResources/Human_Genome/elsi/cloning.html

named Robert Briggs and Thomas King wanted to find out if they could use Spemann’s technique for nucleus transfers on frogs, which are even more complex organisms than salamanders. The method worked, but the frogs grew abnormaly and died just after a few days, so something was wrong. In 1968 the scientist John Gurdon found out that you could use the nucleus from a fully differentiated somatic cell for donating as well. The cloning technology somatic cell nuclear transfer was taking form., but it had to take many years of experimenting and sharpening of the cloning technology until finally in 1997 the first mammal cloned with the somatic cell nuclear transfer technology was born and managed to survive. Out of 277 attempts only one was successful, and it was this one who became Dolly the Sheep. Even though only one out of the 277 attempts had made it (which showed cloning was far from an unriscy procedure) this was a big breakthrough in cloning history. Dolly became world famouse at once, and people started to realise the seriousness in cloning. This was the first real serious case where the clone of a mammal had survived and it made people realise that cloning humans might become reality. But even if it could work scientifically it might not be accepted ethically. After Dollys birth Bill Clinton, who was president in the United States at the time, along with the Congress found a law that banned human reproductive cloning in the United States. Several countries followed the example of creating cloning laws. However cloning research was able to be continued because it could lead to significant medical benefits, etc. 5 After Dolly scientistc succeeded in cloning mice, pigs, goats, cows, and even monkeys who are the human’s closest relatives.6

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5 http://gslc.genetics.utah.edu/units/cloning/clonezone/clzone.cfm
6 http://www.mimersbrunn.se/arbeten/2621.asp


7.3 Is a clone an exact copy of the original organism?
A clone has the exact same DNA as its original, but that is also the only thing that is exactly alike. A clone will not inherit it’s originals thoughts or memory for example, it will not grow
up and have the exact same personality as it’s original. You can compare with twins for example. They have the exact same genes, but already under the development of the embryo, microscopic changes in the enviroment of the uterus make the twins develop differently. Twins grow up to bee two different individuals with different personalitys and interests. Same thing goes for clones. Scientists have even discovered that clones can differ in appearance from the original, which is a result from a vibrating movement that occurs during the cloning. This means that a clone doesn’t have to look exactly like its original. In several experiments scientists have seen that some cloned mice would end up with a different fur color from the original.7
According to a study where researchers studied how much twins that grew up apart from each other would have in common there is a connection between their personality characteristics, intelligence and the risk of having the same mental diseases. They found out that about 25% of the make up of twins is closely alike, the rest consists of differences. The study could also apply to clones, which means that clones will have some resemblance with it’s original but still develop into a completely independent individual with own thoughts, memories and characteristics.8

7.4 The risks of cloning
Cloning is vary risky. The failure rate is extremly high, and even if a cloning attempt is
successful problems often occur later. For every 100 cloning attempt only about 1-3 clones

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7 http://www.mimersbrunn.se/arbeten/2621.asp
8 Ibid


are made, which means that the sucess rate ranges from 0.1 percent to 3 percent. The reasons are probably many, but some could be that:
• The enucleated egg and the transferred nucleus may not be compatible
• An egg with a newly transferred nucleus may not begin to divide or develop properly
• Implantation of the embryo into the surrogate mother might fail
• The pregnancy itself might fail

If a clone however is able to survive there are often alot of problems that arise during the animals development. Some clones have for example developed kidney or brain malformations and impaired immune systems. Another common problem is that alot of clones have a tendancy to become much larger than their originals (Large Offspring Syndrome). They have larger organs which could lead to breathing problems, blood flow, and other problems.9 Clones also seem to have higher rates of infection and tumor growth, and they often mysteriously die at a very early stage. For example, the first cloned sheep in Australia seemed completly helathy on the day she died, and even after an autopsy the cause of death couldn’t be determined. This makes it hard for the scientist to study the aging process of clones.10

7.5 Can humans be cloned?
Researchers have already started to clone human embryos, but mostly because to harvest stem
cells and not to create human clones. Scientists believe that stem cells can be used in the

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9 http://gslc.genetics.utah.edu/units/cloning/cloningrisks/
10 http://www.ornl.gov/TechResources/Human_Genome/elsi/cloning.html#risks


search after cures for many diseases sush as diabetes, strokes, cancer, AIDS, neurodegenerative disorders like Parkinson’s and Alzheimer’s disease, etc. The human embryo cloning started in 1998 but this far the cloned embryos have died after dividing themselfs just a few times. Allthough, the technique is getting better and better and many scientists believe it’s just a matter of time before the technical difficulties of human cloning will be solved.11
In 2001 an international group of reproductive experts announced that they were planning on cloning a human before the year 2003 had come to an end. The group said that a woman would give birth to a cloned baby in January 2003, but they didn’t want to say anything about the scientific details. Their plans were met with scepticism from many other scientists, and this far (nine months after the goal was supposed to be achieved) no cloned baby has been born.12 Many of the worlds political leaders strongly critize all attempts to create human clones.13 It is a global issue that conserns all people around the earth, and should be taken very seriously. When scientific matters suddenly become religious and ethical matters also it’s not quite as easy. In the end only laws can stop eventual attempts to create human clones, which show that even if something is scientifically possible it might not be accepted ethically.

7.6 Pro and con human cloning
The fact that reproductive cloning is very risky (for every 100 experiments only about 1-3 result in viable offspring) and that cloning so far is a subject field with many questionmarks make most scientists and physicians believe that any attempt to clone humans at this time would be unethically irresponsible and considerably dangerous. The same problems that occur

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11 http://www.mimersbrunn.se/arbeten/2621.asp
12 http://gslc.genetics.utah.edu/units/cloning/
13 http://www.mimersbrunn.se/arbeten/2621.asp
with cloned animals (premature death, high infection rates, abnormally large organs, tumor growth, deformations, and malfunctioning organs, etc) would surely apply to a human clone as well. Another matter would be the mental development. Intelligence and mood haven’t been so important factors in the animal cloning, but would be crucuial for the development of a helathy human. With so many questionmarks and risks most people agree that cloning humans is out of the question.14
Beside from the risk-factor which is the largest argument against human cloning there are also other arguments. A strong religious opinion is that cloning is trying to play God and that it interferes with natures own way of developing life on earth. Many people believe that it is not our right to try to create life on our own.15 Another argument against human cloning is that it would reduce the uniqueness of an individual. “It would violate deeply and widely held convictions concerning human individuality and freedom, could lead to a devaluation of clones in comparison with non-clones.”16 There is also a belife that human cloning would change the way we look at people and more or less turn people into objects that can be created and designed to have sertain charactaristics and looks (for example create a clone with the main consern of using it to donate organs). A cloned child might also feel like its living in the shadow of its original, just living as a copy of another person (aspecially if a child is cloned to replace a lost loved one in a family).17
Just as there are people who are agains human cloning there are also people who are positive to it. This group is at the time much smaller than the against-human-cloning-group, but as the technology developes it will probably grow larger. One argument used by people
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14 http://www.ornl.gov/TechResources/Human_Genome/elsi/cloning.html
15 http://www.cs.virginia.edu/~jones/tmp352/projects98/group1/ethic.html
16 http://www.genetics-and-society.org/technologies/cloning/reproarguments.html#1
17 Ibid


who are pro human cloning is that it would be possible for couples who can’t have children to be provided with a child that is genetically related to them. It would also allow lesbians to have children without using a spermdonor. Another argument is that families with genetic diseases could create a perfectly helathy clone to be able stop the disease to be passed forward.18 Also the issues of creating a clone to have a perfect organ donor and to replace a lost loved one are used as arguments for cloning just as well as against. It’s just that some people would find this positive and other negative because of different values.19 Cloning could also help scientist to learn more about how genes work and lead to discoveries of new treatments for genetic diseases.20


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18 http://www.spinneypress.com.au/108_book_desc.html
19 http://www.genetics-and-society.org/technologies/cloning/reproarguments.html#1
20 http://www2.worldbook.com/students/feature_index.asp


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Inactive member [2003-12-07]   Cloning
Mimers Brunn [Online]. https://mimersbrunn.se/article?id=2521 [2019-10-20]

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