Two long-tailed macaques have become the first primates to be cloned using the same process that produced Dolly the sheep. The breakthrough by Chinese scientists could open the door for copying humans in the future.
Image: picture-alliance/Photoshot/Jin Liwang
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Two identical baby macaques named Zhong Zhong and Hua Hua are the first ever primates to be cloned from a non-embryonic cell, researchers in China announced on Wednesday.
The baby monkeys, born six and eight weeks ago, were cloned using a process called somatic cell nuclear transfer (SCNT), according to research published in the scientific journal Cell. It is the same process that was used to clone Dolly the sheep over 20 years ago.
Monkeys cloned in Chinese lab
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Although SCNT had been used to clone over 20 different animal species, primates — a mammal order that includes humans — have been more difficult.
"The barrier has been broken by this work," Muming Poo, director of the Institute of Neuroscience at the Chinese Academy of Sciences in Shanghai told news agency AFP.
The researchers said their work will greatly help medical researchers by making it possible to clone genetically uniform monkeys for studying diseases and medical trials. They are frequently used in research on cancer, brain diseases like Parkinson's, as well as immune disorders.
"In the United States alone they are importing 30,000 to 40,000 monkeys each year by drug companies," Poo told AFP, adding that having cloned monkeys would reduce the number needed for drug tests.
20 years ago, the world was stunned by the creation of Dolly the sheep. Scientists have since tried their hand at copying other animals, from mice and racing mules to kittens and fighting bulls.
Image: picture-alliance/AP Photo/Channel 4
Dolly - the one who started it all
This woolly miracle started out in a test tube and was born on July 5, 1996, to three mothers - one provided the egg, the second the DNA and the third was the surrogate. Dolly was the world's first mammal cloned from an adult cell. The sheep that made history lived to be six, when she was put down after developing a lung disease. Dolly is on display at Edinburgh's National Museum of Scotland.
Image: picture-alliance/dpa/PA Curtis
Half horse, half donkey
Idaho Gem is the very first cloned mule. Born in 2003 in - you guessed it - a town in Idaho, he is an identical genetic copy of his champion racing mule brother. Idaho Gem lived up to expectations and became a successful racing mule. Tougher and more productive than horses, mules are a - usually sterile - cross between a female horse and a male donkey.
Image: Getty Images/University of Idaho/P. Schofield
CC cat
The world's first cloned pet was a cat. The Texas scientists who created the clone in 2001 called the furball CC, for carbon copy. Commercial pet cloning hasn't taken off, however, much to the dismay of devoted pet owners.
Image: picture-alliance/dpa
Five sisters
Noel, Angel, Star, Joy and Mary were born on Christmas Day 2001 at PPL Therapeutics - which is the company that helped make Dolly the sheep: The five healthy female piglet clones, PPL said, had the genetic capability to allow their organs to be transferred to the human body without being rejected.
Image: picture-alliance/dpa
Desert beauty
Injaz ("Achievement") is the first cloned female dromedary, that is one-hump, camel. The gangly Arabian camel was born in 2009 at the Camel Reproduction Center in Dubai. Used for transport, riding and racing, camels still play an important role today in the Persian Gulf society.
Image: picture-alliance/dpa/Camel Reproduction Centre
Join the fray
Spanish scientists cloned a fighting bull they named Got. In this 2010 photo, the little fellow, cloned from the tough fighting bull Vasito, doesn't look ferocious yet at all. Got's mom was a serene black and white milk cow surrogate.
Image: picture-alliance/dpa/Bragimo
Monkey biology
Unlike Dolly, who was created using a procedure called nuclear transfer, little Tetra the rhesus macaque was created through a technique called embryo splitting. In 2000, scientists in Oregon presented the little primate they had successfully cloned for the first time. Above, Tetra, which means four in Greek, is four months old.
Image: picture-alliance/dpa
Fido forever?
A team of researchers in South Korea managed to clone the first canine in 2005: the Afghan hound Snuppy. In 2014, a biotech company based in Seoul cloned another dog, this one from a 12-year-old dachshund that belongs to a caterer in London who won the procedure in a competition. The result: Mini-Winnie. Experts, however, warn of cloning pets, arguing the animals won't necessarily be the same.
Image: picture-alliance/AP Photo/Channel 4
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Researchers greet news with caution
The technical feat also brings scientists a step closer to cloning humans, as well, raising a host of ethical concerns.
Although researchers were able to produce two clones using SCNT, their success rate was very low. Out of 127 eggs, only two produced live macaque births.
The SCNT method involves transferring the nucleus of a cell, which includes its DNA, into an egg which has had its nucleus removed. In order to clone primates using this method, fetal cells — rather than adult ones like those used to clone Dolly — were the only ones that proved successful.
"It remains a very inefficient and hazardous procedure," said Robin Lovell-Badge, group leader at the Francis Crick Institute in London, who was not involved in the Chinese work.
"The work in this paper is not a stepping-stone to establishing methods for obtaining live born human clones. This clearly remains a very foolish thing to attempt," he added.
Scientists at the Shanghai institute urged that their method was not intended to be applied to humans. They also called for a debate on what should and should not be considered acceptable practice in cloning primates.
Monkeys have been successfully cloned in the past using a different technique called embryo splitting. The technique mimics how twins naturally occur, but it can produce only four at a time, whereas the SCNT method could, in theory, clone many more.
