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Human cloning

Human cloning is the creation of a genetically identical copy of an existing human or growing cloned tissue from that individual. The term is generally used to refer to artificial human cloning; human clones in the form of identical twins are commonplace, with their cloning occurring during the natural process of reproduction.

Note that cloning is also not limited to humans. However, this article refers to the special case of the artificial cloning of human beings.

The meaning of human cloning is often misunderstood. Although genes are recognized as having some effect on who one is, "genetically identical" does not mean altogether identical; almost no one would deny that identical twins, despite being natural human clones with identical DNA, are separate people, with separate experiences and not altogether overlapping personalities. However undramatic it may sound, the relationship between an "original" and a clone is rather like that between identical twins raised apart; they share all the same DNA, but little of the same environment. Ultimately, the question of how similar an original and a clone would be boils down to how much of personality is determined by genetics, an area still under active scientific investigation. (See Nature versus nurture.)

Table of contents
1 External links and references

Techniques

Currently the most successful cloning technique is the same process which allowed Dolly the sheep to be cloned - somatic cell nuclear transfer. It is also the technique used by ACT, the first company to successfully clone a human embryo (see research section below). An egg cell taken from a donor has its nucleus removed. Another cell with the genetic material to be cloned is fused with the original cell.

Another way of cloning is by parthenogenesis, where an unfertilized egg cell is induced to divide and grow as if it were fertilized. This technique only works on females.

In reproductive cloning, the cloned embryo is implanted in a woman's uterus. This should develop into a normal baby, its only distinction being that it would be almost genetically identical to the DNA donor.

Therapeutic cloning could be used to provide replacement organs or tissue for people who have had theirs damaged. The cloned embryo would contain DNA taken from the transplant patient. After nuclear transfer, the cell would divide to form an embyro and stem cells would be removed. Stem cells could develop into any tissue or organ. These cloned organs would be compatible with the person's immune system, so no immunosuppressant drugs would have to be taken after the operation. Most scientists do not want to clone whole humans.

Speculative possibilities

An extreme but noteworthy goal of therapeutic cloning is to create complete hydroencephalic[?] or otherwise brain-dead bodies for receipt of transplants of the brain (or consciousness, somehow) of the original donor. Advocates of this approach, usually called whole body transplant, include the Raelian movement (reputed to be associated with Clonaid), who see this as a path to immortality. However, this form of therapeutic cloning raises troubling ethical questions, and is viewed by most as more disruptive even than reproductive cloning. Interestingly, advocates of 'downloading consciousness' of human minds (with or without the physical brain) into robot bodies (such as Marvin Minsky) are rarely subjected to the intense criticism reserved for Raelism. Perhaps because the robot idea is viewed as science fiction, while the technology of whole-body transplant seems much nearer-term.

Many of these ambitious schemes rely on misconceptions or wishful thinking regarding the relationship of mind, brain, and consciousness to the body. It is important to dispel myths that somehow clones are 'a copy of' the donor.

Limits of cloning

First, none of these techniques provide exact clones - they would be 99.7% identical to the DNA donor, because some important genes--which are present outside the nucleus, in mitochondria for example. Some of the DNA of the DNA donor would be missing for the clone to be an exact copy, and some of the resulting clone DNA would come from the donor egg-cell. How much change this would lead to in the clone is being investigated, but it could spell problems for therapeutic cloning, where compatibility is essential because of the risk of rejection.

Second, difficulties with cloning organisms from their somatic (non germline) cells tend to lead to (what seems to be) premature aging in higher animals. If a new brain is generated in that body, there is no reason to believe that consciousness, apart from the ethics of the move, can ever be moved from one brain into a new brain even if it is genetically identical. Identical twins often show uncanny parallels in life choices, but rarely do they exhibit any characteristics that would cause one to believe that genetic similarities in brains lead to any kind of compatibility of consciousness. If a brain is moved from an old body to a new one, even a clone, it would continue to lose size and capacity to regenerate cells, and continue to be subject to such disorders as Alzheimer's disease. Given all this, 'immortality' seems a difficult goal to achieve, and even extended lifespan may be at a low quality of life.

Given these limits, the main reason for interest in the speculations is that they may be driving funding for research, and providing active lobbying for legal or political protections for the cloning industry. Concerns regarding the Raelian movement tend to focus on this issues.

The current status of research

In 1998, South Korean scientists claimed to have created the first embryo of a human clone, but the results were never published and many doubt that they had done so.

In the November 25, 2001, issue of the Journal of Regenerative Medicine, a US company Advanced Cell Technology[?] claimed that it had successfully created a clone of a human, in the form of an embryo. ACT vice president Dr. Robert Lanza said that the company's intention was to use this in therapeutic cloning, in order to harvest embryonic stem cells from a patient.

Some scientists objected that the ACT cloning had not actually been successful because the cloned embryos had only divided a few times, meaning it was possible that the transplanted genetic material had not actually been used. Further criticisms were of the company's inability to collect much useful information from the experiment, and of their inability to harvest stem cells. The company stressed that it was against reproductive cloning and they hoped to develop purely therapeutic processes.

Reproductive cloning has supporters such as the scientists Panayiotis Zavos[?], Brigitte Boiselier[?], and Severino Antinori. Antinori claims that a cloned baby will be possible before 2003. However, the majority of scientists, including Ian Wilmut[?], who led the team that cloned Dolly the sheep at the Roslin Institute[?], claim that there are many further complications to reproductive human cloning in its current form. Aside from the ethical questions involved, the scientists claim that it is simply too risky. In a debate for the American National Academy of Sciences[?] Wilmut quoted the low survival rate of cloned animals as evidence that human cloning would be dangerous. The main fears are that children will be born with genetic disorders, which might develop or worsen over the years.

Zavos thinks that by screening[?] embryos before and after implantation this risk would be reduced significantly. Don Wolf, a researcher at Oregon Regional Primate Research Centre[?], disagrees. He suggests that screeners would not even know what to look for.

Zavos works with the Italian infertility expert Severino Antinori, who was recently expelled from the International Association of Private Assisted Reproductive Technology[?] (APART) for his well-publicized wish to be the first to clone a human. Antinori claims that cloning humans would actually be safer than in animals. He quotes research from Duke University, which seems to suggest a vital genetic difference between primates and other animals with regard to cloning. A problem discovered when cloning was first developed was that many of the clones grew much too large in the uterus, consequently dying at birth. A researcher at the university, Randy Jirtle, suggests this is due to the growth controlling gene IG2FR being suppressed. In animals a process known as imprinting can cause this gene not to be expressed. If the remaining gene is also turned off then 'large offspring syndrome' (LOS) occurs. Research he has done suggests that in primates neither gene can be subject to imprinting. Jirtel thinks that because of these extra safeguards, reproductive human cloning would be much safer than cloning of other mammals.

This is disputed by scientists who say that large-offspring syndrome is just one of many problems that result from cloning. Controlling this gene would not prevent many other genetic disorders which have yet to be fully understood or discovered.

Zavos and Antinori also say that the many of the developmental problems in animals were due to non-ideal conditions in which the embryos were cultured[?]. Researchers at the Whitehead Insitute for Biomedical Research[?], MIT, have found that this disrupts genes so that apparently normal-looking animals die early. Zavos points out that reproductive science is actually more advanced in humans due to the widespread use of treatments such as in vitro fertilisation (IVF), and therefore cloning in humans is not such a large step as animal cloning was.

The Whitehead team, however, conclude that reproductive human cloning is not a good idea. They did suggest, though, that therapeutic cloning of organs should be safer. This is because the imprinting experienced during culture is less important when cells specialize and start to grow in to specific tissues.

Claims of success in human cloning

In 1978 David Rorvik[?] claimed in his book In His Image: The Cloning of a Man that he had personal knowledge of the creation of a human clone. A court case followed. He failed to produce corroborating evidence to back up his claims, and his claims are now regarded as a hoax.

Severino Antinori made claims in November 2002 that a project to clone human beings has succeeded, with the first human clone due to be born in January 2003. His claims were received with scepticism from many observers.

In December 2002, Clonaid, the medical arm of a cult called Raelism, who believe that aliens introduced human life on Earth, claimed to have successfully cloned a human being. They claim that aliens taught them how to perform cloning, even though the company has no record of having successfully cloned any previous animal. A spokesperson said an independent agency would prove that the baby, named Eve, is in fact an exact copy of her mother. [1] (http://apnews.excite.com/article/20021228/D7O6OBAO0). Shortly thereafter, the testing was cancelled, with the spokesperson claiming the decision would ultimately be left up to Eve's parents.

A mother in America plans to pay $500,000 to the Clonaid organisation to clone her deceased daughter.

Advantages

Many hopes have been put upon human cloning. Antinori and Zavos hope to create a fertility treatment that allows parents who are both infertile to have children with at least some of their DNA in their offspring. Therapeutic cloning could provide needed organ transplants.

Dr. Richard Seed thinks that human cloning will help us understand, and eventually reverse, the human aging process. A cure for cancer by a better understanding of the cell-differentiation process, as well as better treatments for heart attacks and improved cosmetic surgery, are being cited as being possible with the new technology.

Ethics

Many are against reproductive cloning not just because it is thought to be dangerous, but also because it can be considered a form of genetic engineering - it involves parents choosing the DNA of their offspring. However, some scientists consider it simply as another fertility treatment similar to IVF, which also initially caused controversy that has now largely been resolved.

An argument given by 'pro-life' groups is that because they believe embryos are already human, destroying them is tantamount to murder. Most scientists protest that this is irrelevant - sperm also have the potential to become human, but millions die during intercourse. Some religious groups defend their anti-cloning stand by saying that it is taking reproduction out of the hands of God.
Other arguments are that a human life would be manufactured (made by man hand) with specifications, being treated as an object, instead of being an individual with his own identity, and at risk of being treated as second-class individual. The clone itself could also suffer from feeling himself/herself merely a copy of another individual.

Besides, the cloning process could lead to confusions of relationships between human persons, in terms of filiation, consanguinity, kinship and parenthood.

Another concern raised by some Hindus is whether a cloned human would have a soul. Hindus believe that a pre-existing soul is reincarnated into a new embryo when a man and woman have intercourse. If an embryo is cloned with no intercourse taking place, Hindu theologians are divided on whether or how such a person would have a soul. Other Hindu theologians see a potential spiritual benefit that could derive from cloning some of the great Hindu saints whose bodies have been preserved.

Other arguments of biological nature are calling into question genetic mixing. Reproductive cloning could imply a reduction in genetic diversity : ome biologists consider introducing asexual reproduction (i.e. not-gametic) would limit the unpredictability factor which guarantee diversity in human species.

An argument supporting the banning of embryonic cloning is simply that it is unnecessary - there are many therapeutic treatments being investigated which would have equal benefits. However, some object that this is not an argument to ban cloning, as there is no danger in exploring new alleys of research.

The current law on human cloning

In August 2001 the US House of Representatives voted to ban government funding for all human cloning. This includes not only reproductive but also therapeutic cloning. Current regulations prohibit federal funding for research into human cloning, which effectively prevents such research from occurring in public institutions and private institution such as universities which receive federal funding. However, there are currently no laws in the United States which ban cloning completely, and any such laws would raise difficult Constitutional questions similar to the issues raised by abortion. President George W. Bush is thought to be completely opposed to human cloning in any form.

The British government introduced legislation in order to allow licensed therapeutic but not reproductive cloning in a debate in January. However on 15th November 2001 opposition groups won a High Court legal challenge that effectively blocked cloning of embryos for therapeutic purposes. They discovered a loophole which allows reproductive cloning to be performed also. Anti-abortion groups say that a new debate is necessary because of recent technologies having been developed that might circumvent the need for embryonic cloning. The government overruled this attempt at the beginnning of March 2002 and currently therapeutic cloning is allowed.

Australia has a government committee still considering the issues, having already introduced a variety of regulations on cloning in general. However organisations devoted to clone humans, such as the Raelites and the Las-Vegas based Clonaid, as well as Antinori and Zavos, are very hard to control. Many think these groups would shift their operations to other countries, where a lack of regulation could bring dangerous results.

External links and references

See also: cloning -- stem cell -- genetics -- genetic engineering -- Utilitarian Bioethics -- Cell incubator



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