By Udita Shukla
On January 24, 2018, the Institute of Neuroscience in Shanghai grabbed global news headlines by announcing the successful cloning of two monkeys. Primarily created for the purpose of investigating human diseases, Zhongzhong and Huahua are the world’s first cloned monkeys. The technique of cloning used was the same as the one employed to create the world’s first clone, Dolly the sheep.
The method used
Zhongzhong and Huahua were created by extracting DNA out of artificially grown, genetically modified cells and injecting them into an egg. This is essentially the chief ‘cloning’ step, and the procedure is called a somatic-cell nuclear transfer.
In the last step, Qiang Sun, a researcher at the institute, added two artificial molecules after transferring the DNA, which altered the development of the cloned genes. Essentially, this allowed the cloned genes to be unlocked and enabled scientists to take advantage of the power of the stem cells to develop into any organ.
Significance of the milestone
The creation of ‘Zhonghua’—as the pair are called, referring to the Chinese nation or people—is a sign of the incredible potential of the field of primate research. Particularly as it is an area from which the United States and Europe withdrew some time ago, leaving out China as one of the flag-bearers for this research. Since primates are considered to be the closest cousins of humankind, a similar feat performed on them opens several doors to a more consolidated probe into the biological and physiological development of humans and may hold the key to curing various diseases.
Ever since the world first met Dolly in 1996, scientists were in a race to clone more and more animals, which led to the successful cloning of mice, pigs, dogs, cats, and cows. However, a failed attempt to clone monkeys in 2003, in which 716 eggs at the University of Pittsburgh were used, demonstrated the particular difficulty in cloning this closely-related animal.
Roadblocks in the path of research
Monkeys that were created at the institute in 2016 using the mutated form of the gene MECP2, a gene which is also held responsible for the autism spectrum disorder. When introduced to the company of other monkeys, the cloned subjects chose to run in circles, while rebuffing any interaction with ‘normal’ subjects. Curiously, the aforementioned behaviour tallies with that of children afflicted with the MECP2 mutation.
According to the Director of the Institute of Neuroscience, Mu-Ming Poo, “It is a feasibility demonstration that we can manipulate genes in monkeys, but it’s not a disease model,”. As a matter of fact, the cloning performed to create the MECP2 monkeys offers little control to scientists to study the target disease. Additionally, different monkeys possess this gene in different parts of their genome, which leads to differing behaviours. This variance in the manifestation of the gene-related disease does not support the use of the monkeys for testing autism-related drugs.
Zhongzhong and Huahua belong to the family of Crab-eating macaques, which are estimated to live up to about thirty years. This should give researchers a reasonably long time-window to investigate childhood afflictions they may suffer, but not old-age disorders. According to Christopher Navara, a biologist at the University of Texas at San Antonio, “Cloned and genetically modified monkeys could be very useful for studies of some diseases, but less so for others.”
However, one of the most pressing issues researchers hope to study is the possible occurrence of premature aging, which was also observed in Dolly. Researchers are also interested in any specific impacts the process of cloning may have on primates. Anthony Perry of the University of Bath has cautioned that “You wouldn’t use this approach with all these unknowns. If you want to make a genetic model of disease, the last thing you want is use a model you don’t now much about,”.
Future prospects for this research
Fantastical and intriguing as the concept of human cloning is, Mu-Ming Poo explicitly dismisses the idea. The sole objective of the team remains confined to cloning as many genetically modified monkeys as possible. The technique the researchers are using was only made possible by the emergence of CRISPR—a gene-editing technique that has been widely adopted in research on different organisms around the world.
Substantial investments have been made by the Chinese government into the cloning of primates, in order to facilitate research into the onset and progress of various diseases. Therefore, it is becoming imperative for genetic researchers to refine their current methods with a goal of enhancing cloning efficiency, which still remains quite low. With more primates scheduled to be cloned in the coming months, this field of study is sure to unveil many genetic mysteries. Until then, Zhongzhong and Huahua will keep scientists busy.
Featured Image Source: Flickr
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