Scientists have apparently reversed the process that causes cells to age in a herd of six clone cows, it was disclosed yesterday. The breakthrough could relaunch cloning research and increase the chances of human embryos being cloned to provide replacement body tissue.
Cells from the six cows appear genetically younger than those of normal animals of the same age. The American scientists are unsure exactly how it happened, or whether the cows will live longer as a result.
But they have welcomed the news because one of the big problems of cloning has been the suspicion that it robs cells of a normal life-span.
Dolly, the sheep whose birth marked a cloning revolution, appears to have inherited the "age" of the ewe from which she was cloned. Scientists have since feared that premature ageing might be an unsurmountable obstacle to successful cloning.
Now it seems that, done the right way, cloning not only does not inevitably cause premature ageing, but can even make cells younger. Once the process is understood, say the scientists, cloning could supply crops of youthful cells for a variety of uses.
One area where they might be especially important is to create replacement tissue for the treatment of degenerative diseases such as Parkinson's, Alzheimer's and diabetes, as well as heart, liver and kidney disease.
Dr Robert Lanza, one of the cloning team which reported the discovery in the journal Science, said: "It's really remarkable. Telomeres [tips of the chromosomes] from all of the cows, including one who is celebrating her first birthday this week, look like those of a newborn.
"Our results show that cloning actually has the potential to reverse the ageing of cells. This has profound implications for treating age-related disease and for understanding the actual mechanisms behind the ageing process."
Another member of the team, Dr Vincent Cristofalo from Thomas Jefferson University, Philadelphia, said: "The significance of this finding is that you can, in essence, reset the ageing clock in animal cloning, a development which overturns a previous obstacle to effective cloning.
"The study establishes a basis for far more kinds of cloning experiments that could have significant implications in medicine and agriculture."
The British anti-abortion charity Life said it was worried about some of the implications of the research. National chairman Mr Jack Scarisbrick said: "If it hastens the drive towards cloning using embryonic cells, which inevitably causes the death of a human being, then we would deplore it."