Dolly v.2: elderly, but healthy

Dolly the Sheep clones help prove the safety of SCNT cloning
Animals feel no worse than ordinary sheep, and live no less

marks, Geektimes

A team of researchers from the University of Nottingham said that four clones of Dolly the sheep are subject to the usual age-related changes that are characteristic of all sheep. Previously, some scientists stated that clones should age faster than ordinary organisms.

Evidence that this is not the case was published by biologist Kevin Sinclair and his colleagues in the journal Nature Communications (Sinclair et al., Healthy aging of cloned sheep). They found that the adult sheep Debbie, Denise, Diana and Daisy, all of them clones derived from the same cell line as Dolly, are quite healthy animals. There are no signs of premature aging in sheep (see the press release of Nottingham Dollies prove cloned sheep can live long and healthy lives - VM).

A snapshot from an article in Nature Communications – VM

Twenty years have passed since the cloning of Dolly, and the current study is so far the first work in which scientists have studied the age changes of clones. Clones are created by somatic cell nuclear transfer (SCNT). The genetic information for the cloning process was taken from adult differentiated (somatic) cells, and not from sexual (gametes) or stem cells. The original animal (prototype) itself no longer existed at the time of cloning. And part of his cells, necessary for the experiment, was promptly frozen and stored in liquid nitrogen in order to preserve and transfer genetic material.

The research of scientists from the University of Nottingham is important for science. It refutes the claim that cloned mammals will die quickly due to accelerated aging and age-related diseases. Dolly the sheep, a clone of an ordinary sheep, got lung disease at the age of six, which is characteristic of more "elderly" sheep, and also suffered from arthritis. Scientists have already explained that this is the result of the fact that the sheep was constantly kept indoors, without walking it with other animals. Experts feared that the world's first cloned animal would get sick or an accident would happen to it. But sheep that are kept indoors usually get sick. Dolly's diseases were no different from the diseases of other sheep that were kept in similar conditions.

Nevertheless, it was difficult to refute the opinion that clones are dying due to the rapid appearance of age-related diseases with ordinary words. Supporters of this point of view received another confirmation: in 2002, a cloned mouse died in Japan, which received a whole "bouquet" of age-related diseases. The mouse was relatively young, so the case allegedly confirmed the theory of "suicide clones".

Sinclair and colleagues proved that the main factors that led to the appearance of diseases in Dolly and a mouse from Japan are environmental factors, not genetic factors.

"A lot of research has been done with mice, and in most cases the cloned mice were relatively healthy," says Sinclair. "Sometimes it is difficult to understand why mice show signs of premature appearance of senile diseases, but all this is the influence of specific environmental factors… The devil is in the details."

In addition to the four Dolly clones involved in this study, the scientists studied nine other cloned sheep from three different cell lines. In total, Sinclair and colleagues studied 13 sheep aged 7 to 9 years. This age corresponds to 60-80 years in humans. Sheep were tested for arthritis, diabetes and some other diseases. As it turned out, the organisms of these sheep were in good condition – no worse than the organisms of ordinary, non-cloned sheep.

True, Debbie was found to have arthritis, but other sheep also suffer from it. Scientists have concluded that clones live as long as ordinary organisms that were born in a traditional mammalian way.

Sinclair and his team believe that the data they have obtained as a result of research will help to convey to society that cloning is safe, there are no negative effects when using this method. "People know we're not creating Frankenstein's monsters," says Sinclair.

However, before declaring SCNT cloning completely safe, scientists need to conduct additional research.

Portal "Eternal youth" http://vechnayamolodost.ru  22.08.2016