When Dolly, history’s most famous sheep, was given the chance of life via a cloning technique called somatic-cell nuclear transfer (SCNT), there was concern that a cloned sheep might not be as healthy as a regular one. Not so, according to recent health tests on her ‘sisters’.
Dolly developed arthritis at quite a young age and had difficulty walking, before dying in 2003 at six years old from a type of lung cancer caused by a virus.
Credit: Nature Communications
However, four cloned sheep that are genetically identical to Dolly, having been derived from the same batch of cells, have reached nine years of age – the equivalent of around 70 years in humans. They are still in good health.
The sheep were shown not to be suffering from some conditions that often affect older sheep, such as diabetes and high blood pressure (anyone else thinking: “so in humans those things can’t all be down to the booze and eating hamburgers?”).
“Despite their advanced age…none of the clones showed any clinical signs of disease,” researchers at the University of Nottingham, in England, wrote in the journal Nature Communications.
Dolly’s non-relatives are also doing fine
Nine other sheep unrelated to Dolly also underwent a series of health tests which had generally positive results. Some of the sheep showed signs of arthritis, but nothing beyond what would be expected for any sheep of that age.
Although the cloning technique carries a high risk of premature death or developmental abnormalities in the fetus, the clones that do survive now appear to have a good chance of a long and healthy life.
“From the current series of assessments, we conclude that there are no long-term detrimental health effects of cloning by SCNT for a long-lived species such as the sheep,” the researchers said.
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Image credit: University of Nottingham
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