Science

It Looks Like Dolly The Sheep Didn’t Age Prematurely

Scientists have concluded that Dolly the sheep didn’t age prematurely. Their research suggests that the cloning process is safer than previously believed. Dolly, the sheep, was the first animal cloned from an adult cell. She was born in Edinburgh in 1996 and died at the age of six in 2003. When she died, scientists believed that the cloning process resulted in the genetic problem which resulted in Dolly aging faster, which caused her to develop osteoarthritis.

Dolly The Sheep
By Toni Barros from São Paulo, Brasil (Hello, Dolly!) [CC BY-SA 2.0], via Wikimedia Commons
However, experts at the Universities of Nottingham and Glasgow conducted a radiographic assessment of Dolly’s bones and found out that she wasn’t aging any faster than a normal sheep at that age. The scientists also checked her descendant Bonnie and other cloned sheep, Megan, and Morag, and didn’t find any signs of arthritis.

Professor Sandra Corr, professor of small animal orthopedic surgery at Glasgow University, said in the published paper, “We found that the prevalence and distribution of radiographic osteoarthritis was similar to that observed in naturally conceived sheep, and our healthy aged cloned sheep. As a result we conclude that the original concerns that cloning had caused early-onset osteoarthritis in Dolly were unfounded.”

Scientists created Dolly, using a technique known as somatic cell nuclear transfer. It worked in a way that the nucleus from the cell of an adult sheep was transferred to an egg that hasn’t yet been fertilized, which was then put into a surrogate sheep for birth. Dolly had the same DNA as the donor sheep. Dolly the sheep looked healthy, and scientists used her for mating to produce six lambs naturally. But, near the end of 2001, the sheep started to walk strangely.

The next year, professor Ian Wilmut, the leader of the team which worked on cloning Dolly the sheep at the Roslin Institute at Edinburgh University, said that she was weak and that she was suffering from painful arthritis in her left hind leg, hip and knee. Scientists euthanized her in February 2003. Professor Ian Wilmut said, at the time, that it’s still unknown whether the problems with arthritis were because of the cloning process or they were just a coincidence.

The Nottingham team looked at the skeleton to discover whether Dolly really suffered from premature aging. They went to the National Museum of Scotland in Edinburgh to scan her bones. The team didn’t find any evidence suggesting Dolly the sheep suffered from premature aging. The same group proved that the clones that came from the same cell-line didn’t age prematurely.

“Our findings of last year appeared to be at odds with original concerns surrounding the nature and extent of osteoarthritis in Dolly – who was perceived to have aged prematurely,” added Professor Kevin Sinclair of Nottingham University in a statement.