Contrary to original concerns regarding the death of a cloned sheep named Dolly, new research finds that her death had nothing to do with her being a clone. Experts say that earlier claims are unfounded.
Radiographic Study Of Dolly's Bones
In 2003, the first mammal to be cloned from an adult cell, a sheep named Dolly, was euthanized because of tumors in her lungs. Soon, reports came out presenting concerns that perhaps Dolly suffered from early onset osteoarthritis as a result of her being a clone, leading to debates regarding the possibility of early onset of diseases among cloned animals. However, records state that Dolly had osteoarthritis only on the left knee.
A team of researchers investigated the matter by conducting radiographic studies of Dolly's bones as well as those of other clones' and her naturally conceived daughter, Bonnie, and found no signs of abnormal osteoarthritis. In fact, they state that the osteoarthritis observed in the clones is similar to the osteoarthritis observed in naturally conceived sheep.
The Nottingham Dollies
Interestingly, this team of researchers were also responsible for a previous paper in which they assessed the Nottingham Dollies namely Dianna, Debbie, Denise, and Daisy, the four sheep from whose cell lines Dolly's were derived. The study published last year showed that the eight-year-old Dollies aged normally, while in the current study, they also found only cases of mild osteoarthritis and one case of moderate osteoarthritis among the Dollies.
"As a result we conclude that the original concerns that cloning had caused early-onset OA in Dolly were unfounded," said Professor Sandra Corr of Glasgow University, coauthor of the study.
The study is published in Scientific Reports.
As mentioned, Dolly was the first mammal to be cloned from an adult cell, making her a famous and important sheep. She was a part of an experiment being carried out by the Roslin Institute, which aimed to develop better ways of developing genetically modified livestock and to make useful proteins in sheep milk. Her DNA came from a mammary gland cell, and she was born to a Scottish Blackface surrogate mother on July 5, 1996, although she was announced to the world only months after on Feb. 22, 1997.
Although Dolly lived most of her life at the Roslin Institute, she is said to have lived a normal life even after she was found to have been infected with a virus that causes lung cancer in sheep. She had six lambs with a ram named David and was euthanized in Feb. 14, 2003, at the age of six after she was discovered to have tumors in her lungs.
She was named after Dolly Parton.