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Risks of Animal Cloning
A cloned animal is born and it makes the international press. Yet when you look behind the headlines you will find that for every success, there are dozens, sometimes hundreds of failed attempts. Animal cloning is still a notoriously difficult and inefficient process.
For example, to produce Snuppy, the world's first cloned dog, more than 1,000 embryos were created, and only three pregnancies were achieved. The success rate with somatic cell transfer is no more than 3% and this could be due to a number of factors including:
1) An incompatibility between enucleated egg and donor DNA
2) Failure of cloned embryo to implant successfully into the womb
3) The egg with the donor DNA may divide incorrectly
Other risks of animal cloning are that cloned animals have been observed to have higher rates of infection and tumour growth, skeletal abnormalities, lung and heart problems, and some like Dolly the sheep die prematurely.
In a famous study in 2002 by Rudolf Jaenisch and his colleagues at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts mouse genomes were reported to be severely affected by the cloning process. The scientists examined more than 10,000 liver and placental cells of cloned mice and found that up to 4% of the genes functioned abnormally. The problems were not so much with the genes themselves but how they were controlled and expressed.
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Disadvantages of Animal Cloning
One of the main disadvantages of animal cloning is something called Large Offspring Syndrome (LOS) where the cloned animals possess abnormally large organs and these can lead to breathing difficulties and blood flow problems. They can also present difficulties to the mother during delivery.
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Animal Cloning - The Future
The disadvantages seem overwhelming at times; - are these inherent problems with somatic cell transfer that will always be present or do they represent a nascent technology that scientists are still trying understand fully and get to grips with? If the problems are technical then it is likely that in time they will be solved and cloning will become a more efficient process with fewer risks. In his book the Principles of Cloning, Jose B. Cibelli points out that the incidence of LOS for in vitro embryo production of animals is varied with it being higher in some laboratories than others. The reasons given are purely technical: "The culture medium and in particular the use of coculture and the addition of serum have been pointed out as the probable cause for the syndrome ..."
If the problems were found to be an inherent part of the animal cloning process then justification for it to continue (and the suffering it causes) would be on shaky ground.
Despite animal cloning being one of the biggest scientific breakthroughs of the 20th century, scientists do not yet fully understand what really happens when a specialised cell is rewound to its undifferentiated state, implanted into an enucleated egg and then given a jolt into life.
The benefits of animal cloning are immense, both for animals and humans (organ banks for transplants, high quality and healthy livestock, protect endangered species, and more ...), but at what cost? At the moment it is a cost that society is prepared to pay.
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Released into the public domain by Seoul National University (SNU) in South Korea