- Written by Victoria Hill
- BBC News correspondent
“He’s gone,” whispers Gabby Drake, a veterinarian at Chester Zoo, holding a stethoscope to the feathered chest of a 28-year-old bright red tropical parrot.
The chattering lory is an elderly resident of the Chester Zoo and a species listed by the International Union for Conservation of Nature (IUCN) as vulnerable to extinction.
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It is sad to see that this striking and characteristic bird needs to be put to sleep. His small clawed paws are nodular and suffer from arthritis that cannot be treated.
But the unique genetic code contained in his cells does not end there. Several small parts of his body will join the samples taken from 100 species. They will be frozen – stored indefinitely – in the UK’s largest bank of organic living tissues, Nature’s Safe.
In vials filled with nutrient-rich, cell-safe antifreeze, the samples are stored at -196 ° C, the temperature at which all natural chemical processes of the cell are stopped – they stop in the animation.
The idea is that at some point in the future – decades, maybe even centuries – they may be resurrected. This is a frozen backup solution in case of disappearance.
Life resumes its course
Conservationists say we are losing species faster than ever.
Against the backdrop of the biodiversity crisis, which the United Nations says threatens the extinction of a million species of plants and animals, some scientists are now trying to figure out what to put in the freezer the day before.
“It won’t prevent extinction, but it will definitely help,” said Tallis Matson, founder of Nature’s Safe.
Mr. Tallis is a tall, friendly man who does not skimp on the mission of his charity to preserve the living tissue of wild animals.
“From here, life begins again,” he beams, showing me a microscope image of a bottle of cheetah skin cells.
The screen is full of tightly packed skin cells – the building blocks of the body. The black dot in the middle of each connected spiny cell is the nucleus, which contains a unique set of genetic instructions that created, in this case, the now-deceased cheetah.
“This animal died in 2019,” says Tallis Matson. “We woke up these cells a few days ago – and now you see them all over the screen. They have multiplied. “
Skin cells are very useful for this work, especially the type of connective tissue cells called fibroblasts.
They are necessary for the healing and recovery of wounds, and after they are removed from the freezer and heated to body temperature in a bath with the necessary nutrients, they are perfectly divided and multiplied in the dishes.
One possible future use of these cells is the cloning of new animals using these thawed DNA packets.
Animal cloning is not new. In 1996, Scottish scientists cloned a Dolly sheep by merging the cell of one sheep with the egg of another. It is a reproductive technology born in the field of domestic animals and now focused on conservation.
The American biotechnology company Revive and Restore recently made a clone of endangered black-legged ferret skin cells that have been dead for decades. Her eggs were frozen in 1988.
As a result of the fusion of the ferret fibroblast with the egg, an embryo was formed, and the clone – the black-footed ferret Elizabeth Ann – was born in December 2020.
They used the same basic approach to clone Przewalski’s horse – a species considered to be the last truly “wild” horse alive – for $ 60,000 (37,242,815 FCFA). A clone named Kurt lives at the San Diego Zoo.
“It was actually cheaper for the zoo to clone a horse – to bring more genetic diversity to the population of the species in the United States – than to send a horse from a European zoo,” said scientist Dr. Ben Novak, head of Revive and Restore.
What species should we freeze?
Genetic diversity is important. When the population of a species decreases, it can lead to inbreeding. In mammals, the offspring receive a set of genetic instructions from each biological parent. And if these parents are related, the genetic diseases they have are more likely to be transmitted.
According to Dr. Novak, cell banking is not the most cost-effective way to resuscitate genes.
“The guards are fighting for the preservation of the species, but we have not been able to save everyone – the destruction continues.”
“Forward development and banking give us the opportunity to engage in catering in the future,” he added. “If we don’t, we’ll regret it later,” he said.
Biobanks run the risk of sending messages that we don’t need to worry about conserving species today, “because we can freeze them for later,” said Professor Bill Sutherland, a biologist at Cambridge University.
“And there’s the problem of prioritizing what’s going on,” he says. “It would be great to get fabric from 20 snow leopards from 20 different places, but it would be very difficult.”
Instead, Nature’s Safe works closely with European zoos, including Chester Zoo.
When an animal needs to fall asleep or dies suddenly, zoo veterinarians collect tissue for the jar.
“It’s a ray of light,” says Tallis Matson. “The death of this animal actually gives some hope for the future of this species, because we can freeze these genes,” he added.
Although available cans are not an ideal approach, he allowed Nature’s Safe to obtain specimens of species such as the mountain frog, an endangered amphibian that was nearly wiped out by a fungal disease.
She also obtained tissue from the Javanese green magpie, a bird that was on the verge of extinction due to the demand for wild birds. (These almost brightly beautiful birds have excellent and in-demand facial expressions).
Dr. Sue Walker, chief scientist at Chester Zoo, says it’s about preserving as much genetic material as possible. “If we don’t do that when the animal disappears, we lose it,” she said.
Earlier this year, a nine-year-old female Gosha jaguar was found dead in her enclosure in Chester. Veterinarian Gabby Drake carefully cut off the big cat’s left ear, put it in a cold bag and sent it to a safe house before sending Goshi for an autopsy.
“Jaguars are not the most endangered big cats, but they are in decline and face the same human pressure as other big predators,” says Gabby.
“She was quite a young animal, and unfortunately she never had children. It’s sad, but it’s nice to know that her living tissue will survive. ”
Today, several pieces of pea-sized velvet black ear of Gosha – cleaned, prepared and filled with a protective nutrient solution – sit in a box with liquid nitrogen, which grows in biodiversity.
Tallis Matson is optimistic that science may allow in the future. “With gene editing technology, we can even create new genetic diversity,” he suggests.
Looking at the now lone male jaguar patrolling his enclosure, Dr. Sue Walker of Chester Zoo says it could be decades before we have the technology to do what we want to do with these specimens.
His hope, like most conservationists, is that the use of frozen cells from long-dead animals will never be needed.
“But if we don’t collect them, those genetic elements will be lost forever,” she said. “We will lose all this unique biodiversity.”