Should extinct species be revived?

Finally, others are considering the possibility of completely cloning a mammoth …

Lionel Cavin : In 2019, a Japanese team announced that it had discovered the presence of biologically active elements in the cells of a mammoth that died 28,000 years ago and preserved in the permafrost of Siberia. This suggests to the most optimistic that one day we will be able to recover cells that are still sufficiently active to recover preserved DNA, allowing this mammoth to be cloned, i.e. to insert its genome into an elephantocyte. It would be the same mechanism as the one that worked in the 1990s for the sheep Dolly. Others consider this impossible: We will never find mammoth cells active enough in the permafrost for their genome to be complete and preserved.

In fact: is not cloning a chimera when we see the fate of the Pyrenean ibex?

Nadir Alvarez : This method of cloning has in fact already been used at the beginning of the millennium for a subspecies of Spanish ibex, but the rebirth took place only a few years after the death of the last individual (living cells were taken from the last representative of the species), and it thus created goat lived only for about ten minutes. The manipulation was not optimal as the ibex was carried by a goat while the researchers could have used a ibex as a surrogate mother. With this technique, instead of reviving the species, we could try to amplify the number of certain species at critical risk of extinction. We would then no longer be talking about extinction, but about a kind of genetic and demographic rescue procedure.

Some scientists are thinking of reviving extinct species from samples taken from museums?

Nadir Alvarez : As soon as an organism dies, its DNA fragments almost instantly under the influence of enzymes. Despite this, it was realized that relatively short stretches of DNA could still be sequenced from samples taken from samples kept in collections. The first convincing demonstration was published in 1989 by the team of a Swedish geneticist, who amplified a DNA fragment from a piece of skin of a taxidermied thylacin, stored since 1869 in the Zoological Museum at the University of Zurich.

Lionel Cavin : It is also a museum sample that made it possible to decode the genome of the Christmas ear rat. The latter could also represent a good model species for the development of extinction protocols, given the relatively easy biological and genetic manipulation of these rodents, their large litter (14 pups per female) and their very short generation time (five weeks).

Nadir Alvarez : We would then modify the DNA of a stem cell (or embryonic) of the closest species, whose DNA we would tinker with by inserting specific genes identified thanks to the museum’s sample. Eventually, it would be re-implanted in an oocyte from a surrogate mother of the closest species.

Is there not a risk of, with extinction, diminishing the severity of a species’ disappearance?

Lionel Cavin : Extinction must definitely not compete with the conservation of species. Some biologists believe it would be better to invest the money from extinction in the wages of rangers, for example, to protect endangered species from poachers. But for now, the de-extinction projects remain anecdotal. And the people who invested in the Colossal company, which intends to revive a mammoth, would certainly not have put that money in the WWF …

Nadir Alvarez : We are proponents of sobriety, considering that it is better to protect what already exists than to go further in innovation. But science values ​​eternal progress. We therefore wondered how to combine these two visions. The return of these extinct species would have a strong symbolic impact on people’s minds, as would the emblematic species currently highlighted in protection programs, such as the giant panda or the tiger. For example, if we succeed in reviving the woolly mammoth, megaloceros and woolly rhinos, we will have to reserve huge territories for them in the boreal areas. Large rewilding areas would need to be established to allow them to thrive. It would therefore be thousands of species associated with such ecosystems that would see their habitat protected.

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