The newspaper reported a few days ago that the mummified carcass of a baby woolly mammoth, surprisingly well preserved by permafrost, was found by gold diggers in the Yukon. This is the most complete specimen of the extinct species ever discovered in America.
The little female was 30 to 35 days old when she died around 35,000 years ago. She was probably with her mother when she wandered off to drink water and got entangled in the mud.
Mammoths reached North America via the Bering Land Bridge that connected the continent to Asia a million years ago. The Yukon and Alaska are thought to be where the subtype known as the woolly mammoth evolved, around 300,000 years ago, before spreading to Siberia.
Courtesy picture
The famous baby mummified woolly mammoth found in the Yukon last June.
Contemporaries of the Pyramids
The vast majority of woolly mammoths disappeared at the end of the last ice age, around 10,500 years ago. But because of rising sea levels, a small population became trapped on Wrangel Island in Russia’s Arctic Ocean and continued to live there until it disappeared around 3,700 years ago. . These mammoths, contemporaries of the pyramids of Egypt built between 4600 and 4500 years ago, have disappeared, victims of human hunters and environmental warming.
For twenty years, scientists have been doing research to “resurrect” them; we speak of the “de-extinction” of the ancestors of the elephants. We work from DNA taken from carcasses found in permafrost and from embryos of Asian elephants, the closest current relatives of mammoths. DNA (deoxyribonucleic acid) is a molecule that contains the genetic information (genome) that allows living things to develop, function and reproduce.
A common ancestor
Modern elephants and woolly mammoths share a common ancestor who lived around 6 million years ago.
Modern-day Asian elephants are more closely related to mammoths — sharing 95.8% of their mitochondrial DNA — than those in Africa.
Woolly mammoths are among the most studied extinct animals because of their many frozen remains found in Siberia, Alaska and Canada. With two layers of fur, ears and short tails protected from frostbite, they were well adapted to life in the Ice Age.
DNA, Dolly and the Mammoths
Photo AFP
Dolly the sheep that was cloned.
When the sheep Dolly was cloned from the mammary cell of a Finn-Dorset sheep in 1996, a world first, it was immediately inferred that a single nucleus from any cell might reproduce an entire animal. .
Scientists have thought that woolly mammoths might be “resurrected” in this way.
Their frozen carcasses found all over the Arctic would offer the material needed to recreate a living animal.
Researchers and research organizations in the United States, Germany, Japan, South Korea and Russia have announced plans to resurrect the extinct animal by extracting functional cells from a frozen mammoth and using the genetic material for cloning.
Not so simple, because of the frozen water. Enzymes in living organisms begin to break down tissue soon following death.
Freezing considerably slows down the action of these enzymes, but does not completely stop it, gradually damaging the DNA of the frozen tissues.
Attempts to somatically clone mammalian cells frozen for years have failed.
Create a hybrid
In October 2020, researchers Emmanuelle Charpentier and Jennifer Doudna received the Nobel Prize in Chemistry for their discovery of CRISPR technology. They made history, being the first two women to share this award without male collaboration.
One of the most important discoveries in genetics, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a genetic engineering technique that uses bacteria to identify viruses and split their DNA.
With CRISPR, de-extinction does not require a living or frozen cell of the extinct species. All scientists need are organic remains containing DNA fragments.
These fragments make it possible to discover the complete genome of the extinct animal (a process called “sequencing”).
CRISPR allows scientists to edit the DNA of its closest living relative to create a new genome that approximates the genetic code of the extinct species. The genomes of some twenty extinct species, including several types of mammoths, have already been sequenced.
Resurrect the species
A young Texas biotech company, Colossal Biosciences, has chosen CRISPR gene technology to resurrect the woolly mammoth. Colossal aims to bring the woolly mammoth back from extinction by 2027. The company’s scientists will insert DNA taken from the carcass of a woolly mammoth into the genome of an Asian elephant to form an “elephant-mammoth hybrid”.
Harvard University geneticist George Church is a co-founder of the company, which in March 2022 raised $60 million to accelerate the development of genetic tools and technologies, such as software and artificial wombs to develop his mammoth embryos.
So they won’t be recreating a real woolly mammoth, but rather a cold-adapted hybrid that can roam the tundra where mammoths lived 11,000 years ago.
Colossal also plans to recreate hybrids of the woolly rhino, a relative of the critically endangered Sumatran rhino.
A March 2017 study published in the journal Nature Ecology & Evolution revealed that de-extinction programs would be incredibly expensive.
The scientists behind the study believe that public or private money spent on deextinction efforts would be better spent protecting existing species.
A 2019 UN report estimates that one million species of animals, plants and fungi are at risk of extinction over the next few decades.
AN IBEX IS BORN FROM A GOAT
Photo AFP
A Pyrenean ibex before the disappearance of the species.
We have so far only succeeded once in reviving an extinct species by genetic cloning, the ibex of the Pyrenees. The last died in 2000.
In 2003, in Spain, the in vitro conception by cloning and the birth of the recently extinct mammal was carried out with cells from skin biopsies taken in 1999 from the ultimate living representative of the species.
A cloned embryo was transferred into the uterus of a surrogate goat. Arrived at term following five months of pregnancy, the embryo was born by Caesarean section. He only survived seven minutes in the open air, due to a lung defect.
Surrogate mothers wanted
The problem with the mammoth resurrection is not the mammoth, but the elephant.
The deextinction of mammoths would involve the use of a large number of female elephants. Surrogate mothers to raise the little woolly mammoths before releasing them into the tundra. How many decades before recreating large-scale herds?
And elephants are not lab mice. Researchers can fertilize hundreds of mice. Impossible with elephants. Scientists would need far too many pregnant elephants. The number of female elephants in captivity of breeding age is limited and artificial insemination fails most of the time. Of 27 pregnancies recorded in the United States, eight ended in miscarriages or stillborn calves. Six others died shortly following birth. Hence the research on artificial wombs.
A Pleistocene Park
Most of those engaged in deextinction research don’t simply want to resurrect ancient iconic animals as a zoo or circus attraction.
Colossal Biosciences wants to help endangered Asian elephants adapt to the freezing environment of the tundra. A “Pleistocene Park” is envisioned for woolly mammoth hybrids. Nothing to see with jurassic park. It would be a national park in which the fauna, flora and natural environment would be protected from human activities.
A 155 square kilometer area in northern Russia is where it is hoped to restore the ecosystem that existed when mammoths populated the region. Researchers Sergey and Nikita Zimov are already testing their theories on the ecological and climatic effects of “rewilding” (rewilding).
Bringing woolly mammoths back to life would be good for the environment. They ate grasses and shrubs and fertilized the soil with their manure. They played a vital role in maintaining the grass cover that once isolated the permafrost from the Arctic plains.
When these great grazing beasts disappeared, the grassy cap declined, allowing the permafrost to thaw and the release of massive volumes of greenhouse gases accelerating global warming.
The “Pleistocene Park” would be a place where the Siberian permafrost would once more be insulated by treeless grasslands on which vast herds of mammoths, wild horses and bison would graze.
And then… humans
Photo AFP
A blood sample taken from a woolly mammoth carcass by Russian scientists in 2013.
The discovery of CRISPR has revealed a new method of DNA editing, which might even make it possible to modify human genes, some of which are the cause of hereditary diseases. This raises serious ethical issues.
It’s not science fiction. In 2018, a Chinese biophysicist, He Jiankui, modified a gene in human embryos to give them resistance to HIV. Three of the modified embryos were transferred to women in the city of Shenzhen.
Dr. He in 2019, was sentenced to prison for “illegal medical practices”. He was released last April following three years in prison. Nothing is known regarding the health of the three children.
The experiment drew strong criticism in China and around the world.
The use of an edited human genome may have introduced errors into the girls’ genome. Even the smallest changes in DNA might have myriad unpredictable consequences.
In February, two Chinese bioethicists asked Beijing to do genetic analyzes of CRISPR babies to determine if their bodies contain genetic errors that they might pass on to future generations.
Not to mention the intentional mutation of embryos in the hope of creating “better” humans.
