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Three cheers for China’s cloned monkeys

The cloning of primates is a great scientific breakthrough.

Academic and author Stuart Derbyshire hails the scientific possibilities of the successful cloning of non-human primates in China.

It’s likely that you have heard of ‘Dolly’ the sheep, famously announced as the first mammal ever to be successfully cloned, in February 1997 (Dolly was born in July 1996). Dolly was a product of Somatic Cell Nuclear Transfer (SCNT), which involved taking an adult cell from the udder of a female sheep and using the nucleus from that cell to replace the nucleus of an egg from another female sheep. The egg was successfully encouraged to fuse with the new nucleus using electric shocks and then began to divide as would a normal embryo. The fused egg was implanted into a third female sheep for gestation. Dolly, bizarrely, had three mothers, and was a genetic clone of the mother who donated the udder cells.

Last week, scientists from Shanghai’s Chinese Academy of Sciences Institute of Neuroscience reported that they had used a similar SCNT technique to clone two macaque monkeys – called Zhong Zhong and Hua Hua. Cloning of animals by SCNT had been previously reported in 23 other mammal species, including mice, cattle, pigs, rats, cats and dogs, but had never before been reported in a primate species. The relative genetic closeness of humans and monkeys has generated a lot of hand-wringing and concerns about the now nearer possibility of human cloning.

Most reports have, however, downplayed that possibility. The eventual birth of Zhong Zhong and Hua Hua followed the production of 260 early embryos, resulting in 43 pregnancies of which 41 failed. Such failure rates would not be tolerated as reasonable to produce human offspring. Also, the SCNT technique used to produce Zhong Zhong and Hua Hua were only successful with cells taken from foetal, rather than adult tissue. The attempts made with adult tissue all failed. Although we do have a primate clone, therefore, we still do not have a primate clone generated from adult cells as was the case for Dolly. That makes the prospect of cloning as a fertility treatment, and more fanciful suggestions of rearing a clone of an adult or recently deceased relative, currently distant. Continue reading