Why is it in news?

Researchers at the Institute of Neuroscience in Shanghai have cloned monkeys using the same technique that produced Dolly the sheep two decades ago, breaking a technical barrier that could open the door to copying humans.

Details

• Zhong Zhong and Hua Hua, two identical long-tailed macaques, were born eight and six weeks ago, making them the first primates — the order of mammals that includes monkeys, apes and humans — to be cloned from a non-embryonic cell.
• It was achieved through a process called somatic cell nuclear transfer (SCNT), which involves transferring the nucleus of a cell, which includes its DNA, into an egg which has had its nucleus removed.
• Researchers said their work should be a boon to medical research by making it possible to study diseases in populations of genetically uniform monkeys. But it also brings the feasibility of cloning to the doorstep of our own species.
• Humans are primates. So (for) the cloning of primate species, including humans, the technical barrier is now broken
• Genetically identical animals are useful in research because confounding factors caused by genetic variability in non-cloned animals can complicate experiments. They could be used to test new drugs for a range of diseases before clinical use.
• Since Dolly — cloning's poster child — was born in Scotland in 1996, scientists have successfully used SCNT to clone more than 20 other species, including cows, pigs, dogs, rabbits, rats and mice. Similar work in primates, however, had always failed, leading some experts to wonder if primates were resistant.
• Even so, their success rate was extremely low and the technique worked only when nuclei were transferred from foetal cells, rather than adult ones, as was the case with Dolly. In all, it took 127 eggs to produce two live macaque births. But It still remains a very inefficient and hazardous procedure.
• The research underscores China's increasingly important role at the cutting-edge of biosciences, where its scientists have at times pushed ethical boundaries. 

About Somatic Cell Nuclear Transfer (SCNT)

• Somatic cell nuclear transfer (SCNT) is a laboratory strategy for creating a viable embryo from a body cell and an egg cell.
• The technique consists of taking an enucleated oocyte (egg cell) and implanting a donor nucleus from a somatic (body) cell. Somatic cells are those which are derived from other parts of the body which are normally non reproductive in nature.
• It is used in both therapeutic and reproductive cloning.
• Dolly the Sheep became famous for being the first successful case of the reproductive cloning of a mammal.
• "Therapeutic cloning" refers to the potential use of SCNT in regenerative medicine; this approach has been championed as an answer to the many issues concerning embryonic stem cells (ESC) and the destruction of viable embryos for medical use, though questions remain on how homologous the two cell types truly are.

Conclusion

This breakthrough can open the gateways for cloning human beings in the future. However, the procedure is still difficult and not efficient enough for commercial use for now. Also, the existing ethical issues remain and they would increase as the research for developing cloned humans gains traction. 

Source

The Hindu