Those of you who survived the roarin’ 1990s will almost certainly remember Dolly the Sheep, who was created from a single adult cell that was combined with an egg cell that had been stripped of its DNA. In other words, Dolly was a clone. Dolly was all over the news when she was born in 1996, but soon after, she started to suffer from health problems, with many people assuming that she was facing these issues because she was a clone.
A new study of 13 cloned sheep, including four from the same cell line as Dolly, is showing that may not actually be the case. While Dolly was plagued early on by problems like osteoarthritis and eventually had to be put down in 2003 because of a tumors in her lungs, the clones studied here seem to be aging without many problems.
Though the study, which was led by developmental biologist Kevin Sinclair and a team of scientists from the University in Nottingham in England, says that it observed “no clinical signs of degenerative joint disease apart from mild, or in one case moderate, osteoarthritis in some animals,” it also states that somatic-cell nuclear transfer (the process by which the sheep were cloned) has “no obvious detrimental long-term health effects.”
This is pretty big news, as the health problems Dolly experienced brought into question the overall healthiness of cloned animals. Specifically, people wondered if the fact that Dolly was cloned caused her to age prematurely. This study shows that isn’t necessarily the case, as the sheep in the study have lived longer than Dolly, though it seems more samples would have to be taken before we can decisively say that clones grow up to be just as healthy as natural born specimens.
Still, this is encouraging news for the world of cloning. While it’s nice to see that these sheep are doing well, this study may not do much to clear up the ethical questions surrounding cloning, which have been at the forefront of the debate since Dolly was born 20 years ago. Time will tell, but don’t expect the controversy surrounding cloning to go away anytime soon.
This study was published in the journal Nature Communications under the title “Healthy ageing of cloned sheep.”