Leviathan Press:

According to the statistics of scientists, since the birth of the earth, 98% of the creatures that have appeared have been extinct. Therefore, many experts warn us that with the destruction of living environment, over-exploitation of natural resources, pollution and climate warming caused by human activities, the earth is experiencing the sixth mass extinction. If this is the future we really have to face, then this time we humans are to blame-even if the statement that "humans have eliminated 60% of the species on the earth" is incorrect, we still need to consider the deep motivation to save these endangered species.

Some people say that human beings have played the role of God here, restoring endangered species and even reappearing extinct species through technical means. This looks beautiful intuitively, but is it really necessary for human beings to "hand of God" on the basis of their own moral guilt? After all, God doesn't need to save himself, but human beings, in the final analysis, still need to save themselves.

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At the moment, Tulis mattson's helicopter is over the South African Game Reserve. The helicopter hovered over the gray land scattered by shrubs, and he could only recognize a running male elephant in the dust.

This monster full of strength and fear is on the rampage. The elephant has been shot in the abdomen by two darts containing sedatives, but it is still fighting the anesthetic effect and refuses to fall down. It panicked and ran to a nearby puddle. The helicopter circled on the way to stop it: if the elephant fell into the water, it would drown.

This deadlock was quickly broken. The elephant fell to the ground and squashed a bush. The helicopter landed next to several trucks. Next is a magical scene.

A group of people hurriedly rolled over the elephant to help it breathe smoothly. It used to be prone, but now it's sideways.

Mattson, 53, from Shropshire, England, wears khaki pants and sunglasses, just like a policeman. He knelt down beside the elephant and put its genitals in a device like a giant condom. A conservationist puts in a probe, which can release a weak current to stimulate the elephant's prostate (and then stimulate the elephant to ejaculate). This method is called electrical stimulation sperm collection.

They began to work. After collecting semen, they packed their instruments, climbed into the helicopter and circled in the air until the elephant woke up and slowly left.

Mattson sent me a video about this strange scene through WhatsApp, which was shot on 20 19 10. He said it was one of the best experiences of my life.

The collected elephant semen is taken back to the farm in mattson for storage, and then it will be used for breeding projects. According to the data of the Royal Society for the Prevention of Cruelty to Animals (RSPCA), the stillbirth rate and infant mortality rate of captive elephants are high. As this endangered animal will face extinction in the next few decades, conservationists and elephant shelters will cooperate to collect semen samples of wild elephants and transport them to shelters in other places in order to improve the survival rate of future generations through artificial insemination.

But mattson is neither a patrolman nor an elephant protector. He runs a horse racing artificial insemination company and serves his farm in Shropshire, England. The company collects and stores the sperm of the winning stallion for reproduction. He may not be the son of God to save the animal kingdom, but this is exactly what he will become.

Mattson has transferred its skills from horses to endangered animals, and plans to build the largest animal cell biological sample bank in Europe. From June 5438 to February 2020, he founded Nature's SAFE, a charity, with the purpose of collecting 50 million genetic samples, putting them into a "time freezer" and keeping the cells of some extremely endangered species in a low-temperature storage tank, including the Far East Leopard, the black rhinoceros and the pheasant frog.

He cooperates with institutions such as Chester Zoo, European Association of Zoos and Aquariums, and researchers from Oxford University, hoping to collect and preserve sperm samples-and, of course, eggs and other tissues. One day, these samples may be used to increase the number of decreasing species and prevent them from extinction.

When we first communicated, his organization was only one month old, and 30 samples have been collected, including tamarind monkey, elk, Colombian spider monkey and leopard chameleon. "What we have done is just a drop in the ocean," he said. "We want to be the seed bank of the animal kingdom, just like the Millennium seed bank."

Endangered tamarind monkey. Tim Flach

Conservationists are always attracted by the idea that maybe we can not only protect endangered species, but also revive extinct animals. In the past decades, in order to make up for the harm caused by human activities to animals, they have been fighting this defeat.

In 2003, environmentalists made history. Under the excited gaze of scientists, a goat gave birth to the Pyrenees goat (locally called Bucado goat). In the past 200 years, hunting has reduced the number of Pyrenees sheep until there is only one left. The last goat, Celia, was killed by a fallen tree three years ago.

However, a team of the Agro-ecosystem Nutrition Research and Technology Center of Aragon Autonomous Region of Spain, led by the scientist José Folch Pera, revived this extinct animal for the first time.

Farchy Pera and his team used liquid nitrogen to freeze the skin cells in the ear of the last Pyrenees goat when it died. They later thawed the samples, cleared the DNA of 208 domestic goat egg cells and replaced them with the DNA of the sample cells. These eggs were transferred to the surrogate mother's stomach. Surrogate mother is another subspecies of Spanish goat, which is a hybrid of goat and wild goat.

Although the probability of pregnancy is not high, only seven goats are pregnant, but in the end they successfully gave birth to a Pyrenees goat.

The light of victory is fleeting. The Pyrenees goat born by caesarean section died of respiratory problems only about 7 minutes later. Autopsy showed that the lamb's lungs were abnormal, although other organs looked normal. Now, this species may become a special species that experienced two extinctions for the first time.

Resurrection failed, but scientists confirmed a simple hypothesis: frozen cells of extinct animals have the potential to resurrect species. Farchy Pera mentioned in a paper on cloning in 2009, "Our current work encourages the storage of tissues and cells of all endangered species or species that meet the requirements to some extent, because they may be of great use in future cloning-based species protection."

In 20 19, the United Nations released a report that 1 10,000 species of animals and plants will disappear in the next few decades. Many species, such as black rhinoceros, Sumatran orangutan and Sunda tiger, have been involved in the whirlpool of extinction-in the case of very few existing individuals, the diversity of gene pool is extremely limited, and only highly inbreeding can be chosen. These species have a low survival rate and are more likely to gradually become extinct. One of the few ways to break this extinction vortex is to introduce DNA that has long disappeared from the gene pool-the DNA of those ancestors who have long died.

Christina Hvilsom is a conservation geneticist at Copenhagen Zoo and a member of the conservation genetics expert group of the European Association of Zoos and Aquariums. She said: "In order to stop or reverse the decline of existing species, we need to take various measures. Establishing a biological sample bank is one of the means. "

The extracted animal cell samples are frozen in a solvent. Sebastian Nevos

Mattson is very tall. Even when he wears an eye-catching lab coat, he walks like a fly in his cropped sweatpants. He said that he entered the field of artificial insemination because "the right time, the right place and the right people". Mattson/Kloc-dropped out of school at the age of 0/6 and plunged into the horse racing industry, starting as a jockey. Later, he was repeatedly frustrated in amateur steeplechase and horse racing breeding. Later, an accident caused the death of a mare and made him turn to artificial insemination.

For more than 30 years, he focused on raising horses, and later helped people who lost their pets clone them. 20 18 attended a meeting in the United States and reached a cooperative relationship with Viagen, a cloning company. It became easier to transport frozen tissue from Europe, so he had other ideas. "I thought, if I can save cats, dogs and horses, why not help save rare species?"

He said that when he first contacted Chester Zoo to express his ideas, they "didn't kick me out of the house directly", but they were not interested in the idea of protecting animals through cloning. "They said no, it's like Frankenstein's work. You must pay attention to some boundaries that cannot be crossed. However, the situation is completely different now. "

Sue Walker is the scientific director of Chester Zoo and the co-founder of Nature Vault. He said that in the past, zoos didn't want anything to do with cloning. The cost of cloning a single animal is very high, and the failure rate is also very high, and the cloned animal is likely to have too high stress level or die young. It is much better to increase the population, protect the habitat and concentrate on saving those species caught in the whirlpool of extinction.

However, time is getting shorter and shorter, and the probability of survival of some species is getting lower and lower. In extreme cases, artificial insemination and cloning may be the best or last choice.

On a cold morning in March, mattson took me to visit the farm in Whitchurch, Shropshire. There is a freezing bucket on the first floor of the main building, which is used to store cell samples. The smaller one looks like a milk mixing bucket, and the two larger ones look like huge dye vats. Mattson walked up the steps, opened a bucket, and white fog formed by cold water vapor rolled out. There is a specially designed compartment with thousands of small test tubes shaped like cocktail straws, each of which contains the DNA of horse racing.

He pointed to the big cryogenic tank and said, "This is liquid nitrogen, which seems to be-196. It makes everything full of vitality. " In order to preserve the cells, mattson's team mixed them with cryoprotectants, which can protect physiological tissues from frostbite, in mattson's words, antifreeze. Last year, his company exported animal semen worth about 60,000 pounds to 2 1 country.

In the next room, there is a special liquid nitrogen storage tank: a yellow barrel the size of a bar stool, which currently stores much less samples than the horse semen barrel. "We definitely need more space," mattson said. "We are now in a race against time. In theory, we need 50 different samples of each species to ensure normal demand. "

Collecting at least 50 samples will provide enough genetic diversity for scientists and make meaningful changes for endangered species; If you clone multiple animals from the same sample, and their genes are exactly the same, there is no way to increase the number of species that can reproduce themselves.

After visiting the laboratory, mattson said that he wanted me to see the "source of income" here. He took me to a vacant lot with a roof. The thing on the right looks like a huge square vault, tilted at some angles. There are two stables in the back: one has a very quiet black mare in it, and the other is empty.

Through the barn door in the distance, I saw Josh Steele, assistant field manager, Teresa Haley and Emily Coombes, breeders of stallions, and a chestnut stallion named Klippi. What Combs is holding looks like a huge brown rubber condom. This term is called "horse's false vagina".

Steele controls the stallion, and Haley recounts the interesting scene that followed. Hailey said, "He's hesitating."

We waited quietly, and the fake vagina kept dripping on the concrete floor. There is not much dignity in this scene. Klippi hissed and stamped his foot. Haley said, "Think about it." Her voice echoed in the cold wind, "thinking", a short pause, "thinking"

Mattson joked: "This is the strike up a conversation stage. They are only meeting for the first time and may need a little wine at first. "

When Clippy made up his mind to take the next step in public, everyone acted quickly. Combs cleaned the horse's penis with cloth and bucket to prevent bacteria from contaminating the sample. Then they lead it to the fake horse, put on a fake vagina, insert it several times, and the work is finished.

This may not be decent, but the safest way to get sperm is this rather primitive trick, so that you can sell sperm to those who want high-performance horse racing. This is at least a little more civilized than what happened to elephants in South Africa (sometimes this is the only way to get genetic material from wildlife).

Steele admits that this is indeed a bit strange work.

Mattson is in the natural vault laboratory.

The owners of most samples in the storage tank of "Natural Vault" could not see mattson's team with their own eyes-they were dead before they arrived at the laboratory in mattson.

The sperm extraction method used for horses or elephants cannot be used for all animals: for example, the Thai pig-nosed bat, the smallest mammal in the world, is about 3 cm long; For example, the Antarctic blue whale weighs about 180 tons.

There are not only problems of organization and coordination, but also problems of different rules and regulations in different countries. For example, the code of ethics of the Royal Veterinary College stipulates that veterinarians may not obtain DNA samples of endangered animals in captivity, and may not obtain them after the animals die, unless there are legitimate reasons such as medical examination.

Chester Park will send their samples to the mattson team 40km away from the south after the animals die, and keep them in liquid nitrogen tanks in time. Walker said: "You may imagine an ambulance speeding by in the fast lane, and the alarm keeps ringing. In fact, it is far from being so exaggerated. "

Zoologists in the zoo will take care of animals when they are dying. These experts usually need to deal with animal health problems every day. At this time, they will perform normal surgery and take out testicles or ovaries and tissue samples. Then they will call mattson and his team and ask them to take these samples.

This is why there is a little thing that looks like a black ear and two bat testicles the size of an olive nucleus on the experimental platform of mattson Farm. Seba short-tailed leaf-nosed bats in Chester Zoo usually live in the "fruit bat forest", and visitors can also feed them as part of the "experience" worth 56 pounds.

Although this bat is not on the endangered list at present, no animal is absolutely safe, because the diversity around the world has reached a critical point. The owner of the testis died of natural causes, but its genes will be passed on.

The first thing Lucy Morgan, a scientific consultant in the nature vault, did was shave her ears. "To some extent, ears will grow for life, and ear cells will continue to grow and update," she said. "So, if you want to choose a sample for cultivation in the future, ears are very suitable."

She disinfected her ears in chlorhexidine solution and timed them. Two minutes later, she put her ear in a Petri dish and cut it into chocolate chips. She used tweezers to put them in a freezing tube containing liquid nitrogen. Two small testicles will be preserved intact. They don't take semen out of it-for animals that are too small, they usually can't preserve semen in the usual way.

Animal tissues, testicles or ovaries are safely put into freezing tubes or wheat tubes through pipettes and kept in a freezer, which may be thawed when used in zoos or wildlife breeding projects in the future. As for animals that cannot be artificially inseminated with sperm or eggs due to physiological and anatomical characteristics, samples may be preserved for decades.

Now, all the samples of the "natural vault" are kept in one place, but they aim to establish a branch so that the organization can store them in different places to reduce the storage risk.

Semen samples were stored in wheat straw in liquid nitrogen frozen state.

Mattson's plan seems grand, but it is not unprecedented. The San Diego Zoo in California, 8000 kilometers away, has been running the biological sample bank project since 1970s, and has preserved more than 10000 samples of living cells, germ cells and embryos. This sample bank, named "Frozen Zoo", has hatched several pheasant chicks and witnessed that frozen cat oocytes (cells that can form egg cells) can mature and form late embryos after in vitro fertilization.

In 2020, the conservationists in San Diego made another great achievement. They successfully cloned a black-footed ferret from animal samples that have been dead for 30 years. 65438+February 10, this beautiful ferret was born in a research institute in Colorado and was named Elizabeth Ann by researchers. It looks exactly like the dead ferret Willa in 1988. In the 1980s, this population was regarded as an endangered species, but due to the smooth progress of the breeding project, the population increased by 6,000.

However, the problem is that the existing ferrets are closely related. Ryan Phelan is a non-profit organization focusing on cloning technology, Resurrection &; Executive Chairman of Reconstruction, he said: "Advanced reproductive technologies, such as cloning, can help us save animal populations and restore some diversity that will disappear over time."

Like-minded people also organize sample bank projects for academic research. They are eager to collect as many samples as possible-not to restore the animal population, but mainly for future research. Their work is pragmatic: if we can't save animals, then at least we have enough materials to study them before they disappear.

This sample library includes Ambrose monell's frozen collection in the American Museum of Natural History. The frozen tissue laboratory of the American Museum of Natural History can store as many as 6.5438+0 million samples. At present, samples of butterflies, frog feet, whale skins and crocodile skins are kept in liquid nitrogen storage tanks.

There is a similar sample bank in Britain-"Cryoarks", which is the first national-level animal biological sample bank used in the research of animal species genes and genomics in Britain. The "Frozen Ark" has three freezing bases: one in the British Museum of Natural History, one in the Scottish National Museum and one in the Edinburgh Zoological Museum.

Two other biological sample banks, the European Association of Zoos and Aquariums and the Frozen Ark, are also cooperating. "This means that we don't have to collect animal samples in the wild," said Michael Bruford, the lead researcher and director of the Frozen Ark. This will bring many benefits, not only the least interference, but also the convenience of logistics. But it is extremely true that too many species represented by the samples in our hands have become extinct. They no longer exist. "

Fortunately, the huge sample bank of "Frozen Ark" was established earlier than the San Diego Zoo and the "Nature Vault": this means that people have more opportunities to study animals that died out earlier and unlock valuable information about ecosystems and habitats that have long since disappeared.

Wilsot said that the "natural treasury" not only extracts DNA for veterinary medicine or research, but also "raises it to a higher level", focusing on cell lines and germ cells for artificial reproduction. "Their work has given more meaning to the gene pool of biological samples. What is being done now, and what will be realized in the next few years, is that these cell lines can be transformed into pluripotent stem cells (universal cells that can produce any kind of cells or tissues), and they can differentiate into germ cells, so it is possible to create new animals. "

Brared stressed that it is necessary not only to ensure that the stored genetic material is not only from a few captive animals, but also to ensure sufficient diversity in the gene pool. "If you count the global freezing institutions, people have the ability to store millions of samples. But the question is not how many samples we can store, but the source of these samples and whether we can use them correctly. " He said, "In a sense, this is the role of the frozen sample bank, because researchers and environmentalists can see which samples are available and choose the best strategy."

But there are still gaps in the collected samples, which Brared calls "past mistakes". Animals that are not so pleasing to the eye are usually excluded from the collection because they are forgotten or more difficult to preserve. Most of these gaps are invertebrates such as earthworms. He said: "Whether they are the most attractive animals on earth or not, they are the most important creatures in the ecosystem because of their contribution. However, there are almost no biological samples. "

This is a cloned horse, and its cells come from a racing horse that died in 2008. Sebastian Nevosat

At the beginning of one of the films, Jurassic Park, before dinosaurs began to eat people, ian malcolm in fur coat was played by Dr. Jeff Jeff Goldblum, who criticized the famous theme park owner john hammond john hammond on ethical issues. Sir attenborough richard plays: "Your scientists are obsessed with whether they can do it or not. They don't stop to think about whether they should do it or not."

This is to the point. If we resurrect creatures that have disappeared for decades, then people have reason to resurrect creatures that died hundreds of years ago, such as saber-toothed tigers, dodos, woolly mammoths and even Tyrannosaurus Rex.

Teruhiko Wakayama, a Japanese geneticist, successfully cloned new cells from frozen 16 years old mouse cells. This brings more hope for the resurrection of long-extinct species. But it is not easy to resurrect mammoths and dodos. Although their bodies are frozen, DNA will be gradually inactivated over time, so we lack enough genetic information to revive healthy new individuals.

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However, scientists published the almost complete genome of mammoth last year, although this animal has been extinct for about 654.38 million years. This makes people speculate that it is possible to synthesize the DNA of mammoths artificially. In March, 20021,the research team that cloned the ferret with black feet established the mammoth resurrection scholarship in the laboratory of George Mcdonaldchurch, a famous geneticist at Harvard Medical School, to explore the science of reviving mammoths.

In March, in a telephone chat, I asked Church about the ethical dilemma of resurrecting extinct animals. Why clone extinct animals instead of saving species that are not extinct?

Church's woolly mammoth project is not to resurrect extinct species. He explained: "It aims to give the diversity of extinct species to modern species to help existing species and their ecosystems." By editing oligonucleotides related to certain traits (independently synthesizing single-stranded DNA sequences with 40 to 350 bases) and inserting ancient woolly mammoth DNA into the genome of Asian elephants, Church plans to create a cold-resistant and virus-resistant elephant with ivory that can resist hunters by using CRISPR gene editing technology.

"I really haven't heard that a project is only to revive extinct species, but never to improve the diversity of modern species." He said so. In addition to racing against time and preserving the DNA of endangered animals, he also needs to embed diversity directly into the genes of animals. For example, most of the existing frozen elephant cells were collected in the last decade, but they can also be used as the basis for inserting ancient DNA and providing more accurate DNA sequences from the ancestors of this species, he said.

"So far, the largest number of records of gene editing in a single living animal is 42, and the object is a pig named version 3.0." Church said. For different species, this is not a big change, but it is enough to make some key genes produce very obvious and diverse expressions. If scientists don't have enough animal samples of endangered species, then this editing technology can help fill the gaps in genetic information and may revive millions of species at a lower cost.

Church mentioned that you can actually make the resurrected species more diverse and healthier. "You can include the diversity of different regions and the diversity of different times. You can resurrect two animals that can't live in the world at the same time. They originally lived in different time and space and could not meet. This possibility is very interesting. "

Church doesn't think scientists must ban crossing a certain line, but he warns that you must be very careful when releasing any species into the wild. He mentioned that goats eat the vegetation on the Galapagos Islands after entering the ecosystem, causing soil erosion, threatening the survival of rare plants and affecting the lives of local animals, such as giant elephant turtles. The goat had to be cleared later.

Wilsot believes that cloning for the purpose of protection is very different from cloning for the purpose of reviving extinct species. She said: "At least for me, there is a clear line between helping endangered species increase their numbers and trying to revive the extinct mammoth."

She believes that we can-and should-restore animal habitats and make up for the damage caused by human activities. She believes that cloning technology can only be used if we have no choice.

Mattson, who lives in Shropshire, England, holds a similar view. "I'm worried that people will be addicted to things like Jurassic Park and forget the original intention of saving existing animals." He said, "Now people's ambitions don't stop there."

The "Natural Treasury" follows the strict ethical procedures of the zoo and signed a memorandum of understanding to ensure that all partners are informed. All the samples in the "natural vault" belong to the zoo, which will decide whether to use them for conservation or breeding projects, while the only samples that can be thawed in the former are only used for routine testing to check whether the preservation conditions are reasonable or not. Today, unsaved samples are used in ongoing projects.

When we visited the farm, we stopped at a spacious paddock. Mattson motioned us to see a white horse named "Marka Gem", which was born on 20 1 1 and cloned from a famous obstacle-crossing performance horse "Gem Twist" who died in 2008.

We watched the horse pacing and eating grass, and finally it found us and ran away. Mattson said, "Interestingly, this horse is exactly the same as the original one. Every cell is the same, only 2 inches (about 5 cm) shorter. " It is possible that the mare who gave birth to the original horse is taller or pregnant for a long time. Twenty years after cloning the Pyrenees and 25 years after cloning Dolly, the field of genetics is still full of mystery.

Text /Natasha Bernal Translation /Yord Proofreading/Pharmacist Original/www.wired.co.uk/article/natures-safe