Animal science in the spotlight: 20 years since Dolly the Sheep

This month marks the 20th anniversary of the creation of Dolly the sheep - the first animal to be cloned from an adult cell.

At the time, researchers had successfully cloned mammals by splitting embryos in a test tube and implanting them in adults, but none had managed it using an adult somatic cell. 

Scientists at the Roslin Institute in Scotland managed to produce Dolly from the udder cell of an adult sheep after 276 attempts at trying.

Dolly’s creation was a breakthrough for scientists as many had started to wonder if cloning mammals was impossible.

Ian Wilmut, the scientist who led the team that created Dolly, said research on her led to unexpected and important results. 

"The birth of Dolly and the new understanding of the opportunity to change the functioning of cells made researchers consider other possible ways of modifying cells," he told Live Science

In 2006, researchers in Japan found that introducing a set of four proteins into these skin cells led to a portion of them to "become very similar to embryo stem cells," where they had the ability to then differentiate into different adult cell types, Wilmut said.

"The whole stem-cell investigation was really stimulated by the fact that Dolly was able to be born, and stem cells still are quite promising as a means to be able to repair human tissues when they're damaged," said Lawrence Brody, director of the Division of Genomics and Society at the NHGRI. 

"We're obviously not there yet, but it is something that could be traced back to the success of Dolly.”

There is also a link between the Dolly experiments and the so-called CRISPR technologies that allow scientists to edit genomes, Brody added.

No ordinary sheep: Seven facts you might not know about Dolly

1. Dolly was named after the singer Dolly Parton

2. She was cloned from a cell from a six-year-old Finn Dorset sheep and an egg cell taken from a Scottish Blackface sheep

3. Dolly was not the first ever cloned mammal - the first was a sheep was cloned from an embryo cell and born in 1984 in Cambridge. What made Dolly so special was that she had been made from an adult cell, which no-one at the time thought was possible.

4. Dolly spent her life at The Roslin Institute and, apart from the occasional media appearance, led a normal life with the other sheep at the Institute.

5. Over the years, Dolly had a total of six lambs with a Welsh Mountain ram called David. 

6. Dolly was put to sleep on 14th February 2003 at the age of six, after a scan showed she had tumours growing in her lungs.

7. After her death, the Roslin Institute donated Dolly’s body to the National Museum of Scotland in Edinburgh, where she has become one of the museum’s most popular exhibits.

Facts via the Roslin Institute