The development of cloning technology has progressed rapidly since it was first performed on a sheep named Dolly. Scientists are now applying it to pets to endangered species so it can be duplicated.
Dolly the sheep
On July 5, 1996, a lamb was born which would later inspire the entire biotechnology industry in terms of cloning. Dolly's cloning success also provided a foundation for scientists to find new ways to help preserve endangered species.
In fact, Dolly was changing medical science in ways it could not before. Dolly is no ordinary sheep. It was cloned from a cell taken from the mammary gland of another sheep, as part of experiments conducted by the Roslin Institute in Midlothian, Scotland.
At that point, scientists had experimented with cloning several times since the 1950s, when British biologist John Gurdon discovered a way to clone African frogs.
Despite repeated attempts, repeating this process in larger mammals has proved extremely difficult if not impossible.
But like many other scientific breakthroughs, the experiment that gave birth to Dolly finally materialized after repeated failures.
"Dolly the sheep clone showed the world that it is possible to program all the DNA in the nucleus of an adult cell, and that cell will behave like an embryonic cell again, capable of giving rise to a new animal," said Robin Lovell-Badge, who heads the Stem Cell Biology Lab and Developmental Genetics at the Francis Crick Institute in London, quoted from the BBC.
After unexpectedly creating an embryo, scientists at the Roslin Institute placed it inside a third sheep, which eventually gave birth to Dolly. This incident shocked and confused the general public and much of the world's media at the time.
The emergence of regenerative medicine
In 1996, Japanese surgeon Shinyi Yamanaka felt that his career was on the rocks. He felt he spent too long in the operating room.
In the midst of his busy life, Yamanaka then takes care of the rats in the laboratory. Yamanaka also reads an article that scientists have successfully cloned a sheep, namely Dolly.
He was fascinated by the fact that adult cells could be reprogrammed in this way, and began to wonder if adding DNA transcription factors could reprogram each adult cell back to an embryo-like state.
After a decade of focusing on this experiment, Yamanaka achieved his goal, first with mice and then in human cells. The technology he developed allows skin or blood cells to be reprogrammed to a state that can be converted into any type of cell in the body, by adding a mixture of four transcription factors.
Yamanaka's findings were considered a breakthrough, and he was awarded the 2012 Nobel Prize for Physiology and Medicine. Yamanaka's work has received great attention because the technology allows scientists to take blood samples from patients and create organoids that behave identically to cells in their own bodies. These can be used to test new drugs, vaccines, or to simply understand some basic processes in the human body.
The technology behind cloning also has some direct medical applications. Scientists at the Oregon Health and Science University Center for Embrionic Cell and Gene Therapy used steps similar to those in Dolly's cloning process to help prevent a rare mitochondrial disease being passed from female patients to their children.
Pet clone
In 1996, the Roslin Institute that "created" Dolly was threatened with bankruptcy and faced cuts to the government's budget.
Dolly proved to be a lifesaver. The resulting scientific furor caught the attention of the Texas-based company ViaGen, which purchased the intellectual rights to their cloning technology in 1998.
This acquisition provides enough cash for the institution to survive until they obtain new funding. Initially, ViaGen wanted to use cloning to improve the quality of livestock breeding, a process that is still ongoing today, especially for high-value livestock such as bulls.
Some researchers also use a combination of cloning and genome editing to create animals that are resistant to some common diseases, such as bacterial tuberculosis and salmonellosis infections.
However, since the last six years a new industry has emerged, offering pet cloning services. In 2015, ViaGen began offering its services to pet owners who wish to clone their beloved cat or dog.
Reviving extinct species
Human embryos were successfully cloned in 2013, but the process of 'creating' a complete human being was too risky and unethical.
In recent years, scientists have begun to think about using cloning technology to revive animals that are almost extinct.
ViaGen once cloned the black-footed civet and Przewalski's horse, both of which are endangered. Then in China, they cloned pigs and horses. Pig cloning can even be done completely by robots.
Then there were scientists from the Colossal Biosciences lab who used Crispr-Cas9 gene-editing technology to revive the now-extinct Thylacine.
It's not just the Tasmanian tiger that was revived from extinction in this way. They also intend to revive woolly mammoths or ancient elephants.
Preserved DNA fragments of a woolly mammoth or elephant found frozen in the Arctic tundra, suggest that these large mammals could 'rise from the grave'. To note, most of the woolly mammoths died approximately 10,000 years ago.