Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave us Dolly the sheep. These monkeys are not actually the first primates(灵长类)to be cloned. Another one named Tetra was produced in the late 1990s by embryo(胚胎)splitting, the division of an early-stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus(原子核)with DNA from a differentiated body cell. This Dolly method, known as somatic cell nuclear transfer(SCNT), can create more clones and allows researchers greater control over the edits they make to the DNA.
Success came from adopting several new techniques. These included a new type of microscopy to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, it would be far too inefficient, far too unsafe, and it is also pointless.
But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species, thus cloning humans is closer to reality. However, their research purpose is entirely for producing non-human primate models for human diseases; they absolutely have no intention, and society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough a novel model system for scientists studying human biology and disease.
