Clone mammoths to protect the climate?

The search for mammoth remains is part of the fields of action of paleogenetics, a relatively new science, based on the use of ancient genomes for various purposes - discovering ancient genetic sequences for use in medical or other needs, cloning ancient animals, genetic engineering for the improvement of plant and animal species, dating an ancestor In common, finding a degree of genetic kinship between an extinct species and an existing species based on comparing genetic sequences, dating the appearance of hereditary diseases among early humans, dating traits of different species and more

In the Siberian tundra, the frozen region in northern Siberia, a scientific experiment is taking place called the "Pleistocene Park" (the period from 2.5 million years ago to the Holocene, the period from 11,000 years ago to our time). Russian scientists, with the support of American scientists, are examining the possibilities of cloning mammoths from the remains of organic material of mammoths found frozen under the ice, in an attempt to revive the woolly mammoth that lived in the area until about 3,000 years ago. It is hypothesized that the mammoths would survive there much better than their relatives, the woolless elephants. Assuming that mammoths, like their elephant relatives, liked to fell trees, tens of thousands of woolly mammoths could change the landscape in the tundra and the Siberian taiga (the forested area south of the tundra). The opposite process happened in Yellowstone Park a few years ago, when wolves introduced into the park drove the elk into the thicket of the forest. So trees grew on the banks of the river, their roots stopped the drift of the earth into the river, as a result the river deepened, many fish, birds and wild animals returned to it, And the face of Yellowstone Park has changed from end to end.

The best-preserved woolly mammoth carcasses yet discovered,  Were discovered in 2007 and 2010. Already in 2008 deciphered 3 billion base pairs from the mammoth's DNA - about two thirds of the entire genome. in 2015 decodes Partial genomes of two mammoths. One lived about 4,300 years before our time, and the other - about 44,000 years before our time. In 2019, Japanese and Russian scientists found living cells in the corpse of a young mammoth that lived about 28,000 years ago, And they succeeded To transplant part of her genome into mouse cells, in an attempt to use the mouse's cell nucleus as a supportive environment for DNA replication. Replication stopped due to the poor condition of the DNA after 28,000 years, in which it was exposed to bacterial attacks and ultraviolet radiation: from the DNA sequence left Only a part of the 4.7 billion base pairs in the DNA of the mammoth (the DNA of the mammoth, and of its living relatives, the elephants, is about 1.5 times longer than human DNA, which includes about 3 billion base pairs).

The search for mammoth remains is part of the fields of action of Paleogenetics, a relatively new science, based on the use of ancient genomes for various purposes - discovering ancient genetic sequences for use in medical or other needs, cloning ancient animals, genetic engineering for the improvement of plant and animal species, dating a common ancestor, finding a degree of genetic kinship between an extinct species to an existing species based on the comparison of genetic sequences (for example comparing Homo Sapiens to Homo Neanderthalensis), the dating of the appearance of hereditary diseases among the primitive man, the dating of traits of different species (for example the discovery that the Neanderthals did not digest lactose) and more.

If blood is found in one of the mammoth corpses preserved in the witness ice, it will be the "holy grail" of the cloning field, because so far Were based Cloning attempts on DNA are very partial. And yet, even if such a finding is found, it is likely that the DNA will already be significantly destroyed due to cosmic radiation as well as due to the cessation of the functioning of repair enzymes as happens naturally after death.

The researchers compared the partial genome of the mammoth with the genomes of its closest living species, the African elephant and the Asian elephant, whose common ancestor lived about seven million years ago. By comparison, the difference between the genomes of these species is only half the difference between us and our closest relatives, the chimpanzees. on the basis of the comparison believe The researchers that a change of 400,000 base pairs Will suffice To create a chimera, a kind of hybrid creature, which will be gifted with features that will allow it to survive better in the Arctic Circle and the Siberian tundra.

The stated intention is not to create a "Pleistocene Park" (on the weight of "Jurassic Park"), among other things in light of the ethical problem involved in restoring extinct species to life in a world that is no longer adapted to them, but to create techniques that will help prevent the extinction of species at risk. However, as we know from cloning attempts made in recent years, the very existence of a technology may lead scientists to use it despite ethical concerns and limitations.

And why is it so important to cut down trees in Siberia, whether by mammoths or by other means? The global warming scenario suggests that the melting of glaciers will raise the sea level, reduce the return of the sun's rays from the glaciers to space (because they have melted and become smaller), and thus increase the warming and the greenhouse effect, in a circular process. In addition, the melting of the ice may cause the release of methane trapped in the ice. The effect of methane gas on global warming is ten times greater than the effect of carbon dioxide.

In the equatorial regions, cutting down trees reduces carbon dioxide absorption by the rainforests and thus contributes to the greenhouse effect. In the Arctic Circle, on the other hand, the expected scenario is the opposite: cutting down trees will cause grass to grow, which will better reflect the sun's rays out of the atmosphere than forest vegetation. If the Siberian tundra has grass instead of trees, the sun's rays will be returned better and thus global warming will be reduced. An alternative scenario holds that exposing the soil by eating the grass will cool it by clearing the surface of the soil and allowing wind to pass more easily. This way the low temperature of the surface will be maintained and the melting of the glaciers will decrease. Another explanation suggests that a layer of trampled grass and snow compacted by the footsteps of the large animals will increase the insulation and deepen the layer of ice (permafrost, permafrost, whose thickness ranges from a few meters to a kilometer and a half, depending on the region), and thus keep the danger of methane release at bay. Whatever the correct scenario will be - This is where the mammoths come in. Their role is supposed to be felling trees and devouring their saplings.

In the rain forests, such a solution will not work: cutting down trees will not lead to the growth of grass but to tropical vegetation. The effect of the soil insulation will not cause the sun's heat to return to space, as is the case thanks to the Siberian glaciers.

The plan is to create dozens of large parks in northern Siberia and implement in them the attempt to bring the mammoths back to life. The factory does not provide an answer to the ethical questions: Should we bring back to life an extinct species, when reasonable, from the experience of Dolly the sheep and other cloned animals, that the individual's life expectancy will be short and the quality of his life will be poor?

In addition, the creation of a mammoth individual will probably be carried out by incubation among a carrier of another species, probably an elephant, and it is likely that for this purpose it will be necessary to transplant parts of a mammoth's genome into an elephant's cell nucleus. Will the child be a mammoth? Probably not. Our genome has a percent or two of Neanderthal genome, and we still don't claim to be Neanderthals or to have resurrected them.

Many of the extinct species became extinct not only because of human activity but because of changing environmental conditions. It is possible that even if we bring an extinct species back to life, it will become extinct again due to its unsuitability to the environment, as happened to more than 99% of the species that have ever lived. The chances of extinction of a revived species are greater due to the lack of genetic diversity. The restoration to life will include Few details only, and thus a variety of pairings that would create more genetic variations would not be possible - a basic condition for adapting to new and constantly changing environments.

Another problem is that the ancient habitat of the mammoths has undergone a significant change in the last tens of thousands of years. Many grasslands in Siberia have been transformed into coniferous forests. If the mammoths return to their previous environment, this environment will no longer be their natural environment. The whole idea of ​​the experiment is that the mammoths themselves will make the environment natural to them again, by eating young trees and felling old trees, as their elephant cousins ​​do. The question is - are we not late? Has the environment changed in the last thousands of years to such an extent that cloned mammoths can no longer turn the wheel back?

Meanwhile, as long as the cloned mammoths are only the product of theory and do not actually exist, this discussion is also theoretical. And yet, such a discussion takes place with passion in scientific circles. A kind of preparation for the big day, literally, and the search for the holy grail of the clans is still going on - a frozen mammoth tissue preserved in the snows of the Siberian tundra well enough to be able to clone from it Hundreds of thousands of mammoths May they thunder across the tundra, change the environment and continue to keep the witness ice securely fastened in place.

Additional sources:

- Ross Andersen, "Pleistocene Park", in The best American science and nature writing, 2018. ed: Sam Kean.

This article was published in Atlantic magazine in 2018. Andersen is the scientific editor of the magazine and formerly the deputy editor of Aeon magazine and the scientific editor of the Los Angeles Review of books.

Sam Keane He is a popular science writer who has authored four books in various fields of science, some of them bestsellers. He has written for the New York Times and New Scientist, among others. One of his books was nominated For the award A. or. Wilson for scientific writing.

– Riley Black, Can We Bring Back Mammoths From Extinction? Probably Not — Here's Why, Discover Magazine, March 9, 2020

On deciphering partial genetic sequences of mammoths in 2015:

Palkopoulou, E. et al., "Complete Genomes Reveal Signatures of Demographic and Genetic Declines in the Woolly Mammoth", Current Biology, April 23, 2015

DOI: https://doi.org/10.1016/j.cub.2015.04.007

On the chances of cloning mammoths:

Loi P., Saragusty J., Ptak G. (2014) 'Cloning the Mammoth: A Complicated Task or Just a Dream?' In: Holt W., Brown J., Comizzoli P. (eds) Reproductive Sciences in Animal Conservation. Advances in Experimental Medicine and Biology, vol 753. Springer, New York, NY. https://link.springer.com/chapter/10.1007%2F978-1-4939-0820-2_19

More of the topic in Hayadan:

• Neanderthals and mammoths shared a genetic load of adaptation to cold conditions
• The hairy mammoths had light and dark fur depending on the effect of a gene also found in humans
• Scientists have deciphered the DNA of mammoths for the first time: close to Asian elephants