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Cloning creates abnormalities, ICSI doesn't, report finds

2 July 2004
By BioNews
Appeared in BioNews 265

American researchers have revealed that cloning causes abnormalities in resulting embryos, but they found no evidence of defects in those created by other assisted reproduction techniques. The researchers were trying to investigate concerns that assisted reproductive technologies increase the risk of the rare genetic disorders Beckwith-Wiedemann and Angelman syndromes.

Drs Takumi Takeuchi and Gianpiero Palermo, of Cornell University (US), presented their findings to the annual conference of the European Society for Human Reproduction and Embryology (ESHRE). They created mouse embryos by three different methods: ICSI (intracytoplasmic sperm injection), where the  is injected into the egg; by parthenogenesis, where an egg is induced to become an embryo without sperm; and SCNT (somatic cell nuclear transfer - cloning, where the nucleus of an adult cell is transferred to an enucleated egg. The team then grew the embryos to the blastocyst (16 cell) stage. Survival of the ICSI and parthenogenic embryos was the same as for naturally conceived embryos, but only 30 per cent of the cloned embryos made it to the blastocyst stage. 'This appears to be due to abnormal gene expression we saw in the cloned group', said Takeuchi.

Probing the cloned embryos with fluorescent markers, the researchers found that histone proteins, which bind to DNA, had been chemically reset in the cloned embryos. This reprogramming, known as imprinting, affects gene expression and so could lead to the reduced survival rate. 'Whether it is correctly reprogrammed, we don't know,' said Palermo. The chemical groups on the histones of ICSI and parthenogenesis derived embryos were normal, the researchers found.

The results have added to the debate on reproductive cloning. 'This has made us more convinced that reproductive cloning is unsafe and should not be applied to humans', said Takeuchi, whilst ESHRE, which renewed its moratorium on the reproductive cloning at the conference, described the technique as 'irresponsible and unethical'.

Assisted reproduction may increase genetic defects
The Scotsman |  1 July 2004
Glimpse into cloned embryos reveals problems
New Scientist |  30 June 2004
Scientists renew cloning warnings
BBC News Online |  1 July 2004
Why does cloning create abnormalities? Scientists take a step towards finding out
EurekaAlert |  30 June 2004
19 June 2006 - by Dr Kirsty Horsey 
BioNews reporting from ESHRE conference, Prague (sponsored by Planer cryoTechnology). By Dr Kirsty Horsey: The European Society of Human Reproduction and Embryology (ESHRE), which is holding its annual conference in Prague this week, has again renewed its moratorium on human reproductive cloning. ESHRE began a voluntary five year moratorium on...
20 June 2005 - by BioNews 
BioNews reporting from ESHRE conference, Copenhagen: The European Society of Human Reproduction and Embryology (ESHRE), which is holding its annual conference in Copenhagen this week, has renewed its moratorium on human reproductive cloning. ESHRE began a five-year voluntary moratorium on the cloning of human babies in 1999, in response to...
13 August 2004 - by BioNews 
An Australian study of 37 babies born with Beckwith-Wiedemann Syndrome (BWS) adds to the evidence linking in vitro fertilisation (IVF) and the condition. The researchers, from Murdoch Childrens Research Institute in Melbourne, looked at 37 babies born with BWS. They found a birth prevalence of one in 4000 in children...
29 June 2004 - by BioNews 
BioNews reporting from ESHRE conference, Berlin: A form of IVF in which a single sperm is injected directly into the egg appears to slow down the growth rate of the resulting female (but not male) early embryos, according to a new Dutch study. The scientists, based at the Academic Hospital...
20 January 2003 - by BioNews 
Babies conceived using assisted reproduction technology could be more prone to certain rare genetic conditions than children conceived naturally, a new UK study suggests. Researchers based in Birmingham and Cambridge studied 149 babies with Beckwith-Wiedemann syndrome (BWS), a rare genetic condition characterised by overgrowth of various body tissues and an...
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