Dolly was the exception – Hipertextual

Four of the thirteen cloned sheep studied in the paper published today. Credit: University of Nottingham (UK).

“From the year 1997 there were several criminal acts against the Roslin Institute. There were no signs on the roads to prevent attacks. Dolly he was camouflaged among other sheep to be raised. But a researcher at the institution used to say that when they went with the cameras, she always turned her head, “says Dr. Lluís Montoliu , the National Center for Biotechnology . When he was born the world’s most famous sheep, an intense social and scientific debate about the consequences that could have the technique was generated, including those related to the human species.

“Many of the fears that arose with Dolly have disappeared, “says Kevin Sinclair , first author of a paper published today in Nature Communications . Their study is the first to certify that the surviving clones are just not healthy cloned the sheep. Researchers at the University of Nottingham have evaluated the effects of cloning long-term health of thirteen children, four of them originated with the same genetic material as Dolly. “Black puts on white what we already knew or intuited by other examples in cows, pigs or other species, where the clones were kept for long periods of time,” said Montoliu.

As healthy as sheep not cloned

“Dolly was surprising and extraordinary,” said the scientist at the National Center for Biotechnology. However, in the opinion of Montoliu, draw conclusions from those works on a single animal is the less “complicated”. “It’s a no-brainer, but you have to remember. From that a lot of studies and assessments that generalizaban from data obtained from a single sheep broke loose,” said the expert. One of the great controversies about Dolly revolved around the possible premature aging of the animal, which was slaughtered in 2003 and which was presenting a biological age of ten, depending on the length of their telomeres the “caps” covering the ends of chromosomes.

the work shows that cloned animals pose no major signs of premature aging than those obtained by other means

“concerns about aging and health of clones have been maintained since the birth of Dolly,” says Sinclair to Hipertextual . At work, his team has thoroughly analyzed aspects related to age, such as obesity, blood pressure or arthritis. “We found that our animals are healthy in these three points, and there is no trace of evidence showing aging prematurely,” adds the researcher. “It’s a typical work it takes to get both because the experiments are expensive, as being long-term and require a lot of dedication,” says Montoliu. Regularly cloned animals not maintained or aging studies are done in this case. The results presented show that now “everything that was published when Dolly was not confirmed,” laments the CNB-CSIC scientist.

The work also has a more than obvious historical connotations. In addition to being broadcast on the twentieth anniversary of Dolly, the work comes four years after the death of Keith Campbell , one of the scientists responsible for creating the first cloned sheep. Contrary to what seemed then Ian Wilmut was not the main contributor to this feat of research in biology. Two decades later, the nuclear transfer , the technical name with the technology that led to Dolly is known, “is not so present” in the words of Montoliu. According to the researcher, this is a “very aggressive” approach similar to the process you would use to try to “prick a balloon with a pipe uralita”.

Clones of Dolly the sheep. . Credit: University of Nottingham (UK)

The results of the study in Nature Communications show that there are no differences between clones adults and sheep not obtained by cloning. However, the aggressiveness of the art to which alluded Montoliu has important effects on “fetal and perinatal mortality,” although efficiency has improved in other species such as cows and pigs. This, according to Sinclair, “remains a major problem from the perspective of ethics and animal welfare.” British scientist recalls that natural reproduction processes also present during embryonic development failures. “It’s a matter of time, since for the moment, more difficulties cloned embryos are observed,” he says told Hipertextual .

experts hope the results will help change the negative, a “technical more” in biology that has been overtaken by tools such as iPS cells or genomic editing

perception on cloning according to Montoliu, “we lacked a systematic study” that would prove that Dolly, at least in relation to their health problems, was an exception. In his view, the work has “specific deficiencies” associated with the sample size (only thirteen clones are evaluated) or controls (animals do not have exactly the same age). The CNB-CSIC scientist, despite these drawbacks, said that “we must make virtue” and highlight the longitudinal study. “It is of the few in which has studied the development of clones for so long to check their health,” he says this means. Both Montoliu as Sinclair expect that the findings will help change the social perception of cloning , which is still quite negative. The rejection of public opinion explains, in a way, the European ban on cloned farm animals and to get food from them. Both researchers agree that “there is a rational basis to justify the measure.”

Twenty years after the birth of Dolly, research has advanced. “Until 2006, when Yamanaka said how cell reprogramming was done, a job awarded the Nobel Prize in 2012, we were trying cloning or nuclear transfer as a black box. We did not know what was happening,” says Montoliu. From there the Dolly technique was no longer necessary to obtain pluripotent embryonic cells, because we can get before making the iPS stem cells known. “The main legacy of Dolly was to demonstrate that it was possible to reprogram a fully differentiated animal cell,” says Sinclair. The arrival of new techniques such as genomic editing has enabled add another tool to the box cell reprogramming, where the cloning and the birth of Dolly played a key role.