Cloning humans is widely misunderstood mainly due to its depiction in popular culture. A useful analogy is that of clones being 'delayed [identical twin]?s'. It is debatable how closely a clone would resemble his or her genetic double. A clone shares only DNA with its predecessor, and not any of the knowledge, experience, or environment that shaped him. However studies, such as those on identical twins raised separately, seem to show a strong genetic influence on personality?.
In reproductive cloning this is allowed to divide in to an embryo, which is implanted in to the mother's uterus. This should develop in to a normal baby, its only distinction being that it would be almost genetically identical to the DNA donor.
Most scientists don't want to clone whole humans. Therapeutic cloning, it is hoped, could be used to provide replacement organs or tissue for people who have had theirs damaged. The cloned embryo would contain DNA coming from the transplant patient. After nuclear transfer, cell divides to form an embyro and stem cells are removed. Stem cells are able to grow in to any tissue or organ in the body. These would be compatible with the person's immune system so no anti-immunity drugs would have to be taken after the operation.
In fact these techniques do not provide exact clones - they would be 99.7% identical to the DNA donor. This is because some important genes which are present outside the nucleus in mitochondrion are contributed by the egg-cell. How much change this would result in the clone is being investigated, but it could spell problems for theraputic cloning where compatibility is essential because of the risk of rejection.
In the November 25th 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. These, it is hoped, could be used to grow cloned tissue and organs for transplantation in to the patient. Some scientists objected that the ACT cloning had not actually been succesful because the cloned embryos had only divided so far, 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 them being unable to harvest stem cells. The company stressed that it was against reproductive cloning and they hoped to develop purely theraputic processes.
Reproductive cloning has supporters such as the scientists Dr [Panayiotis Zavos]?, Dr [Brigitte Boiselier]? and Dr [Severino Antinori]?. Antinori claims that a cloned baby will be possible before 2003. However the majority of scientists including [Ian Wilmut]?, who led the first team to clone [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 ethics 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.
Dr Zavos thinks that by screening? embryo?s pre and post implantation this risk would be reduced significantly. Don Wolf, a researcher at [Oregon Regional Primate Research Centre]?, finds this hard to believe. 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 publicised 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]? in Durham, North Carolina 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 down to the growth controlling gene IG2FR being suppressed. In animals a process known as imprinting can cause this gene not to develop. If the remaining gene is also turned off then 'large offspring syndrome' (LOS) occurs. Jirtel, however, claims this is a case of your LOS, my gain. Research he has done suggests that in primates neither gene can be subject to imprinting. Jirtel thinks that because of these extra-safeguards, reproducitve human cloning would be much safer.
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.
Zanos 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. Zanos points out that reproductive science is actually more advanced in humans due to the widespread use of treatments such as In Vitro Fertilisation, and therefore cloning in humans is not such a large step as animal-cloning was.
The Whitehead team, however, conclude that human-cloning for fertilisation treatment is not a good idea. They did suggest, though, that theraputic 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.
Some claims seem more incredible than others. 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 [cosmetic surgery]? are being cited as being possible with the new technology. A mother in America plans to pay $500,000 to the Clonaid? organisation to clone her deceased daughter.
An argument given by 'Pro-life' groups is that because embryos have the potential to grow in to a human, destroying them is tantamount to murder. Most scientists protest that this is irrelevant - sperm also have the potential 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.
An argument supporting the banning of embryonic cloning is simply that it is unnessecary - there are many theraputic 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 [British government]? introduced legislation in order to allow licensed therapeutic but not reproductive cloning in a debate in January. However on 15th November 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. Scientists will now have to wait longer to apply for therapeutic cloning liscenses while the government appeals on the ruling. Pro-Life groups say that a new debate is necessary because of recent technologies having been developed that might circumvent the need for embryonic cloning.
Australia has a government comittee 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 Doctor's 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.
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