Twenty-five years ago, today, a sheep named Dolly became the first animal to be cloned using an adult somatic cell.
The Dolly experiment exploded in the news around the world. It changed the world of stem cell research – and on a more personal level, it kept alive the institute that hosted the experiment.
“Personally, one of the most important things that came from Dolly was the survival of the research institute where I work,” Alan Archibald told DW, who was part of a 1996 experiment facilitated by the Roslin Institute in the United Kingdom. . with a laugh.
“We were facing government cuts. And the money we made selling intellectual property in Dolly kept us going until we found alternative sources of money.”
How Dolly was cloned
Dolly was cloned using a cell obtained from the mammary gland of another sheep. She was born in July 1996 with a white face – a clear sign that she had been cloned, because if she was related to her surrogate mother, she would have a black face.
The researchers named her Dolly after Dolly Parton, who is known for her large “mammary glands” – her breasts.
Dolly was the only baby sheep born alive from a total of 277 cloned embryos.
She gave birth to six babies and died of lung disease at the age of six.
The biggest developments since then
“It simply came to our notice then [cell] “The growth was,” said Archibald. “There was a view that when a fertilized egg had evolved into a multicellular animal, into liver cells and blood cells and brain cells, for these… cells, that was, it was a dead end. There was no way back to alternative places for these cells. “Thus, the reprogramming that was crucial to Dolly ‘s experiment stood at the head of the long – standing scientific doctrine.”
Dolly cloning helped discover the Nobel Prize-winning iPS cells by a team led by Japanese scientist Shinya Yamanaka.
“This is probably the most important development in stem cell research resulting from Dolly cloning,” Dr. Robin Lovell-Badge, head of the Laboratory of Stem Cell Biology and Developmental Genetics at the Francis Crick Institute in London, told DW.
IPS cells offer a way of modeling human disease and are currently used in biological research on premature aging, cancer and heart disease.
In addition, Archibald said the genetically modified heart used in the first human-to-human heart transplant procedure in January was created using Dolly’s technology.
Human cloning
Although a human embryo was successfully cloned in 2013, no progress has been made so far in cloning an entire human.
But monkeys have been copied: in China, Zhong Zhong and Hua Hua became the first primates to be cloned using the Dolly technique in January 2018.
Of the nearly 150 cloned embryos, the surrogate mothers of the monkeys were the only ones to give birth to live babies.
Some progress has also been made in cloning endangered animals. U.S.A. researchers have successfully cloned the black-legged ferret in 2021 and Przewalski’s endangered horse in 2020.
Attempts are currently being made to clone the woolly mammoth, the ever-giant, and the northern white rhino.
Key to producing more food
Along with the ability of cell cloning to study disease, animal cloning allows large industrial farms to produce more food.
The US Food and Drug Administration allows the cloning of cattle, pigs and goats and their offspring for meat and milk production. In 2008, the agency said that food is just as safe as food from non-cloned animals – and therefore does not need to be labeled.
It is not clear how much meat and milk from cloned animals are sold in US markets.
The practice is not allowed in Europe – in 2015, the European Parliament voted to ban the cloning of all farm animals.
But that does not mean that laboratory experiments are not facilitated for EU reasons, Lovell-Badge said.
“The field where cloning processes are actively pursued (including in Germany) is for farm animals as a way to help create or breed pigs or cattle with valuable genetic characteristics,” he told DW.
For example, he said, cells from an animal could be processed by scientists. The cloning methods could then be used to produce animals that carry the new genetic trait, such as disease resistance, or to become more suitable as human organ donors.
Pet cloning
A small industry has been set up around pet cloning. Examples include ViaGen in the US, Sinogene in China and Sooam Biotech in South Korea.
Snuppy was cloned in 2005 in South Korea, Garlic the cat in July 2019 in China and Miss Violet and Miss Scarlett of US singer Barbra Streisand after the death of Samantha’s dog in 2017.
“The excuse for doing this is to ‘replace a lost beloved pet,'” Lovell-Badge said. “However, this is nonsense.”
He said that while it was true that the cloned animal would have essentially the same genomic DNA as the original pet, animals “are not just a product [their] DNA ».
“Even if cloning is successful, the nature of an animal is determined in part by its genes but also by its environment, which means that a clone will never be exactly the same as the original animal,” he said.
Archibald added that although cloning technology is more effective now than when Dolly was made, the process is still quite inefficient.
“You will need a lot of females to lay the eggs that will be used in the process,” she said.
Edited by: Carla Bleiker
Add Comment