Can mammoths be revived by transferring recovered cell nuclei from some of their tissues to oocytes of current species? There is a long way to go, if it is ever achieved. But a group of scientists from Kindai University in Osaka (Japan) has carried out this experiment – with woolly mammoth cell nuclei implanted in mouse oocytes – and has obtained signs of biological activity. Although this does not mean that we will see mammoths scampering through our forests in a few years, it does show that despite the passage of millennia, cellular activity can occur.
In 2012, the remains of a woolly mammoth calf were found preserved in the Siberian permafrost. Yuka – as she was baptized – perished at least 10,000 years ago from injuries sustained by an attack by big cats, and her remains were partially dismembered by humans. It was missing its internal organs, vertebrae, ribs and much of its body mass, but it still had a lot of meat and skin, so it was a great discovery in contrast to the remains of its other congeners found to date – which were just bones.
A first step towards a miracle
In order to resurrect a mammoth, it would be necessary, on the one hand, to find biological samples in a good state of conservation from which to obtain DNA that was not damaged and, on the other hand, for scientific nuclear transfer techniques to be further developed. However, although a cell division has not yet been achieved, the confirmation that a biological reaction can be obtained from cells that are millennia old opens the doors to continue working in this line.
“This marks a significant step for mammoths to come back from the dead, ” says Key Miyamoto, one of the authors of the research. We want our study to move towards the stage of cell division ”. But as he himself admits, there is still a long way to go: “We have confirmed some activity in the mouse embryo, but we are not planning to replicate the experiment with an elephant embryo yet.”
After analyzing Yuka’s tissues, the Japanese and Russian scientists found 88 structures similar to cell nuclei in the muscle tissue that they transferred to dozens of oocytes – female germ cells that give rise to eggs – from live mice. Five of them showed some of the structural changes that precede cell division. But none of them turned into an egg, of course: Yuka’s DNA is badly damaged by the passage of time and freezing, and if you wanted to get a viable embryo, your thing would be to try to combine the mammoth’s cell nucleus with the egg. of some current elephant, a species more related to the extinct woolly than the mouse.
