Since the agency is not requiring food from clones or their offspring to be labeled, consumers are purchasing these novel foods without their knowledge or consent. Center for Food Safety promotes responsible treatmentof food animals and livestock production methods that support biodiversity, human and animal health, and small- and medium-sized farming operations.
We urge further studies to assess long-term risks and environmental threats associated with cloned animals and a moratorium on their release into the food supply continue until these studies have been completed adequately and the products proven safe. Additionally, cloned food already in the food supply should be labeled in order to ensure public awareness, consumer choice and the tracking of potential health effects.
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Please turn off your ad blocker to properly view this site. There currently is no solid scientific evidence that anyone has cloned human embryos. In , scientists in South Korea claimed to have successfully cloned a human embryo, but said the experiment was interrupted very early when the clone was just a group of four cells.
In , Clonaid, part of a religious group that believes humans were created by extraterrestrials, held a news conference to announce the birth of what it claimed to be the first cloned human, a girl named Eve. However, despite repeated requests by the research community and the news media, Clonaid never provided any evidence to confirm the existence of this clone or the other 12 human clones it purportedly created.
In , a group led by Woo-Suk Hwang of Seoul National University in South Korea published a paper in the journal Science in which it claimed to have created a cloned human embryo in a test tube. However, an independent scientific committee later found no proof to support the claim and, in January , Science announced that Hwang's paper had been retracted.
From a technical perspective, cloning humans and other primates is more difficult than in other mammals. One reason is that two proteins essential to cell division, known as spindle proteins, are located very close to the chromosomes in primate eggs. Consequently, removal of the egg's nucleus to make room for the donor nucleus also removes the spindle proteins, interfering with cell division.
In other mammals, such as cats, rabbits and mice, the two spindle proteins are spread throughout the egg. So, removal of the egg's nucleus does not result in loss of spindle proteins.
In addition, some dyes and the ultraviolet light used to remove the egg's nucleus can damage the primate cell and prevent it from growing. Clones do not always look identical. Although clones share the same genetic material, the environment also plays a big role in how an organism turns out. For example, the first cat to be cloned, named Cc, is a female calico cat that looks very different from her mother.
The explanation for the difference is that the color and pattern of the coats of cats cannot be attributed exclusively to genes. A biological phenomenon involving inactivation of the X chromosome See sex chromosome in every cell of the female cat which has two X chromosomes determines which coat color genes are switched off and which are switched on. The distribution of X inactivation, which seems to occur randomly, determines the appearance of the cat's coat.
Reproductive cloning may enable researchers to make copies of animals with the potential benefits for the fields of medicine and agriculture. For instance, the same Scottish researchers who cloned Dolly have cloned other sheep that have been genetically modified to produce milk that contains a human protein essential for blood clotting.
The hope is that someday this protein can be purified from the milk and given to humans whose blood does not clot properly. Another possible use of cloned animals is for testing new drugs and treatment strategies.
The great advantage of using cloned animals for drug testing is that they are all genetically identical, which means their responses to the drugs should be uniform rather than variable as seen in animals with different genetic make-ups.
After consulting with many independent scientists and experts in cloning, the U. Food and Drug Administration FDA decided in January that meat and milk from cloned animals, such as cattle, pigs and goats, are as safe as those from non-cloned animals. The FDA action means that researchers are now free to using cloning methods to make copies of animals with desirable agricultural traits, such as high milk production or lean meat. However, because cloning is still very expensive, it will likely take many years until food products from cloned animals actually appear in supermarkets.
Another application is to create clones to build populations of endangered, or possibly even extinct, species of animals.
In , researchers produced the first clone of an endangered species: a type of Asian ox known as a guar. Sadly, the baby guar, which had developed inside a surrogate cow mother, died just a few days after its birth. In , another endangered type of ox, called the Banteg, was successfully cloned.
Soon after, three African wildcats were cloned using frozen embryos as a source of DNA. Although some experts think cloning can save many species that would otherwise disappear, others argue that cloning produces a population of genetically identical individuals that lack the genetic variability necessary for species survival.
Some people also have expressed interest in having their deceased pets cloned in the hope of getting a similar animal to replace the dead one. But as shown by Cc the cloned cat, a clone may not turn out exactly like the original pet whose DNA was used to make the clone. Reproductive cloning is a very inefficient technique and most cloned animal embryos cannot develop into healthy individuals.
For instance, Dolly was the only clone to be born live out of a total of cloned embryos. This very low efficiency, combined with safety concerns, presents a serious obstacle to the application of reproductive cloning. Researchers have observed some adverse health effects in sheep and other mammals that have been cloned.
These include an increase in birth size and a variety of defects in vital organs, such as the liver, brain and heart. The cause of death was unknown and the carcass was quickly cremated as it was decomposing. However, her early ageing may reflect that she was raised from the nucleus of a 6-year old sheep.
Study of her cells also revealed that the very small amount of DNA outside the nucleus, in the mitochondria of the cells, is all inherited from the donor egg cell, not from the donor nucleus like the rest of her DNA. So she is not a completely identical copy. This finding could be important for sex-linked diseases such as haemophilia, and certain neuromuscular, brain and kidney conditions that are passed on through the mother's side of the family only.
Scientists are working on ways to improve the technology. For example, when two genetically identical cloned mice embryos are combined, the aggregate embryo is more likely to survive to birth. Improvements in the culture medium may also help.
Most of the ethical concerns about cloning relate to the possibility that it might be used to clone humans. There would be enormous technical difficulties. As the technology stands at present, it would have to involve women willing to donate perhaps hundreds of eggs, surrogate pregnancies with high rates of miscarriage and stillbirth, and the possibility of premature ageing and high cancer rates for any children so produced.
However, in South Korean scientists announced that they had cloned 30 human embryos, grown them in the laboratory until they were a hollow ball of cells, and produced a line of stem cells from them.
Further ethical discussion was raised in when scientists succeeded in cloning mice from tissue that had been frozen for 16 years. The Council of Europe has banned human cloning: in fact most countries have banned the use of cloning to produce human babies human reproductive cloning. However, there is one important medical aspect of cloning technology that could be applied to humans, which people may find less objectionable. This is therapeutic cloning or cell nucleus replacement for tissue engineering, in which tissues, rather than a baby, are created.
In therapeutic cloning, single cells would be taken from a person and 'reprogrammed' to create stem cells, which have the potential to develop into any type of cell in the body. When needed, the stem cells could be thawed and then induced to grow into particular types of cell such as heart, liver or brain cells that could be used in medical treatment.
Reprogramming cells is likely to prove technically difficult. Therapeutic cloning research is already being conducted in animals, and stem cells have been grown by this method and transplanted back into the original donor animal. In humans, this technique would revolutionise cell and tissue transplantation as a method of treating diseases. However, it is a very new science and has raised ethical concerns.
In the UK a group headed by the Chief Medical Officer, Professor Liam Donaldson, has recommended that research on early human embryos should be allowed. The Human Fertilisation and Embryology Act was amended in to allow the use of embryos for stem cell research and consequently the HFEA has the responsibility for regulating all embryonic stem cell research in the UK.
There is a potential supply of early embryos as patients undergoing in-vitro fertilisation usually produce a surplus of fertilised eggs.
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