Cloning – the last resort for biodiversity?

A last checking look, then Maya’s paw darts forward. It soon looks like the arctic wolf is about to crush a spider; but her attack is for a treat. A piece of bone lying on the ground just inches from her snout. She pulls it towards her with her paw, digs her sharp teeth into it. The whole world was able to follow their hunting attempts on September 19th. The Chinese company Sinogene Biotechnology Company had presented the scene as a video during a press conference.

Maya is a scientific sensation: she is the world’s first cloned arctic wolf. Her genetic makeup comes from an adult arctic wolf, also named Maya, who died of old age in a wildlife park in northeast China last year. The Sinogene Biotechnology Company had isolated skin cells from the animal, removed their cell nuclei and implanted them in immature, anucleate egg cells from dogs. This procedure is called somatic cell nuclear transfer. This resulted in 137 arctic wolf embryos.

Maya is the world’s first cloned arctic wolf.

All it needed now were surrogate mothers. However, there were not enough female polar wolves in captivity suitable for the experiments. The researchers therefore opted for dogs, more precisely beagles. Because they are genetically closely related to wolves, they are also suitable as surrogate mothers. In the end, the research team successfully transplanted 85 embryos into seven beagles. According to the Chinese daily “Global Times” however, only one of these seedlings fully developed during pregnancy. It was Maya.

Geneticist: Cloning is ‘a small miracle’

“The fact that cloning works is still a small miracle for me,” says Claudia Klein. She heads the Friedrich Loeffler Institute for Livestock Genetics in Neustadt (Lower Saxony). She and her team also occasionally carry out cloning experiments there – but only for research purposes and with farm animals. For example, Klein’s predecessor cloned a Lakenvelder bull in 2006. A cattle breed that is threatened with extinction. The bull has successfully reproduced and fathered offspring in recent years, reports Klein.

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Cloning endangered animal species – that actually sounds like a tried and tested means of protecting species. Before the animals become extinct, they are simply bred in the laboratory. This would prevent stocks from declining sharply or even disappearing forever, thereby throwing ecosystems off balance. In practice, however, such a species rescue is almost impossible.

Many animals, little success

the International Union for Conservation of Nature (IUCN) Red List is getting longer and longer: it now includes more than 41,000 animal species worldwide that are threatened with extinction. That is almost a third of all the species recorded by the organization. The majority are amphibians, closely followed by sharks and rays, mammals, crustaceans, reptiles and birds. Cloning all these animals to save them is unthinkable. Selecting individual species that are worth cloning is, too.

“Cloning is very inefficient,” Klein also points out. The success rate is 2 to 3 percent. This means that if you transplant 100 genetically modified egg cells, a maximum of two to three living cloned animals will be created. This success rate cannot be increased excessively, explains the geneticist. The process is too complex for that. For example, the egg cell has to reprogram the foreign cell nucleus within 24 hours. “It’s like having to learn to fly a jet plane by tomorrow. This will go wrong.”

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The more exotic the animals to be cloned, the more difficult it is to obtain egg cells. Therefore, closely related animal species are often selected as egg cell donors – as in the case of the arctic wolf Maya, who developed from a dog’s egg cell.

Cloning does not work for all animal species

Cloning all endangered animal species is also not possible because not all animals can be cloned. “Cloning is a limited technology that is only compatible with certain reproductive systems,” explains Ben Novak. He is a senior scientist at Revive & Restore – a US company dedicated to improving biodiversity through the genetic rescue of endangered and extinct animals. Only mammals, fish, amphibians and some insect species are currently compatible.

Birds, reptiles, and egg-laying mammals such as platypuses cannot be cloned using somatic cell nuclear transfer. For them, other methods are needed to preserve breeds threatened with extinction: for example, primordial germ cells could be used instead of egg cells, explains geneticist Klein. These are cells from which later the sperm develop in male animals and the egg cells in female animals. In addition to the primordial germ cells, sperm from the animals can also simply be frozen, which can then be transplanted at any time. According to Klein, this method is also suitable for farm animals.

Clones often have health problems

Meanwhile, Revive & Restore is working on new technologies to preserve the genetic diversity of birds. Because: “When populations have greater genetic diversity, they are better able to deal with man-made threats such as exotic diseases, invasive species and climate change,” says Novak. “Cloning complements established conservation methods and, with the right tools, can be a lifeline to secure the future of target species.”

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Novak and his team have cloned a Przewalski horse, for example, as well as a black-footed ferret named Elizabeth Ann. On December 10th she celebrates her second birthday. “She’s an incredible animal that has shown us that cloning for conservation purposes has great promise,” Novak said. However, a uterine condition makes it impossible for her to father offspring. This is by no means atypical for cloned animals: they often have complications, become ill or die.

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It doesn’t work without intact habitats

For WWF Germany, cloning is not a way out of the biodiversity crisis. “Instead of trying to cure the symptoms, we must focus our efforts on eliminating the causes of species extinction,” the environmental organization said on request. “These are above all the destruction of the habitats of animals and plants, the overexploitation of nature, the climate crisis and environmental pollution. That is what we focus our work on.”

Without intact habitats, it makes no sense anyway to clone endangered animal species. They would quickly become extinct again if they could not find food, died out by disease, or were crowded out by humans through agriculture or deforestation.

Biologist Novak therefore sees cloning as a supplementary tool to on-site conservation measures. However, he makes it clear: “Restoring habitats and wildlife corridors will not restore lost genetic diversity.” In the end, both are needed: habitats and genetic diversity. “Saving a species takes many tools and decades of dedication from many people to succeed.”

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