The world's first case! Cloned Arctic wolves, do cloned animals really die prematurely? Can they reproduce?

The world's first Arctic wolf was born through cloning technology, and a second cloned Arctic wolf will be born soon.

This news gives us so many questions, especially when it comes to this special technology of cloning. Why is the Arctic wolf cloned? Will the cloned Arctic wolf age prematurely like the cloned sheep Dolly? Does it have the ability to reproduce? Can the technology be used to "revive" animals that have long been extinct?

Why is the Arctic wolf cloned?

Arctic wolves, also known as white wolves, are a subspecies of gray wolves, with a height of about 70 cm and a weight of about 80 kg. They originated 300,000 years ago and used to live under the same sky as mammoths, saber-toothed tigers, cave lions, and other animals, but the Arctic wolf survived the extremely ice age and became one of the very few polar creatures in the desolate Arctic region, and was also called the "three Arctic hegemon" together with polar bears and Arctic foxes.

Even in the Arctic where it is always minus 40 degrees Celsius, the Arctic wolf can still sleep in the open air, endure hunger for weeks, walk more than ten kilometers at 10 kilometers per hour and chase prey at 65 kilometers per hour. Possessing extremely strong vitality, endurance, and adaptability. But their survival situation is not optimistic.

Because of the lack of food in the Arctic, they have a strict reproductive system, and usually, only the leader of the pack and his wife have the right to mate. Unless the number of wolves in the pack is drastically reduced, the other wolves do not have the freedom to reproduce.

A wolf pack may have only one litter of pups in a year, raised by the whole pack. This special way of reproduction predestines the Arctic wolves to be not too numerous. Secondly, there is the clichéd problem of habitat destruction and rampant poaching, in which at least 200 Arctic wolves are killed every year. Under such circumstances, the Arctic wolf comes to the brink of extinction and is listed on the red list of endangered species.

In contrast, there is no reproductive isolation between wolves and dogs, and both the oocytes and surrogates provided in cloning technology can be canines, like the cloned coyote mentioned earlier, whose surrogate mother is a Beagle. This makes it much less difficult to clone the Arctic wolf, and if it is not only an endangered species but also reproductively isolated from other animals, it may be better to help them reproduce directly by hand.

Will the cloned Arctic wolf die prematurely? Does it have the ability to reproduce?

On July 5, 1996, a day destined to go down in history, the world's first cloned sheep, Dolly, was born. Its birth was considered a major achievement in cloning technology in the scientific world, and people imagined the great changes that cloning would bring, but unfortunately, when Dolly was 6 years old, she was suddenly declared dead, with a life expectancy of half that of a normal sheep.

This poured cold water on people's heads, and many people used Dolly's short life as evidence to claim that cloning would lead to premature aging and many diseases, and that cloning was not as good as they thought it would be, an argument that some people still believe today. Is this the case?

Back in 1999, when the birth of Dolly the cloned sheep set off a cloning frenzy in the scientific community, it was in that year that the famous biologist Yang Xiangzhong obtained cells from a 13-year-old cow and successfully cloned a calf named "Desi". A 13-year-old cow, already equivalent to a human being of more than 80 years old, had already lost her fertility. The 13-year-old cow is already 80 years old and has lost her fertility.

If the age of the cloned animal is calculated according to the age of the cell donor animal, then "Dashi" is 13 years old at birth, and should not have the ability to reproduce. But "Dashi" is very healthy, and in 2001, "Dashi" also through natural reproduction, successfully gave birth to a 40.5 kg healthy calf, so that this argument is not broken.

This result proves that cloned animals can still develop, conceive and give birth to offspring normally, and shows that old cells have been physiologically transformed into new cells after cloning. The cloned animal is not a copy of the mother, but a completely new individual.

And then, a new study by German scientists also proved that during cloning, when the embryo reaches a certain stage of development, telomerase in the cell repairs the telomeres to normal length. Some people may not know what a telomere is. To make a simple analogy, it is like a special clock that divides every time the cell goes, and when the telomere, the clock of life, comes to an end, the cell no longer can divide, and it is the end of the animal's life span.

The telomere length was repaired during the cloning process, which means that the life span of the cloned animal is normal, and the death of Dolly the cloned sheep may just be the imperfection of cloning technology at the time or just the death of a common disease. Because she has a bunch of cloned "sisters", in 2007, a researcher who had participated in the cloning of Dolly used the preserved tissue to clone four sheep, they are normal to live to nearly 10 years old, that is, almost 70 years old, and in good health.

It seems that cloning does not necessarily cause animals to die prematurely, and that cloned animals can reproduce normally.

Can cloning "bring back" extinct animals?

In 2020, scientists in the United States used frozen cells from a long-dead black-footed ferret to clone a new black-footed individual. Once thought to be extinct, the black-footed skunk, a North American endemic, was discovered by a farmer on his farm in 1981 in a small colony.

These black-footed skunks were captured and attempts were made to breed them artificially, but only seven succeeded in producing offspring, so today's black-footed skunks are all inbred, and the black-footed skunk that scientists have "resurrected" through cloning is one of the wild black-footed skunks that did not leave offspring in the first place, and her existence may enrich the genetic diversity of black-footed skunks. They existence of her may enrich the genetic diversity of the black-footed ferret.

However, the black-footed skunk was "resurrected" because its remains were properly preserved. However, in the natural world, through wind and rain, and geological changes, many ancient organisms are left as fossils, and the key to cloning technology is to have complete DNA, trying to extract the complete DNA from these fossils is undoubtedly a difficult task.

The most promising ancient creature to be revived is the mammoth. There are many intact individuals of the mammoth preserved in the permafrost layer of Siberia, and the environment of the permafrost is very suitable for preserving the DNA of the mammoth, but even if the DNA can be extracted, we can't be sure whether the DNA contains other DNA contamination such as bacteria and fungi.

Even the Asian elephants, which are the closest relatives to the mammoths today, are much smaller than the mammoths, and it is uncertain whether the embryos can be successfully transplanted and whether the mammoths can be delivered successfully.

Therefore, it is not impossible to "resurrect" those ancient creatures through cloning, but it is very difficult and the chances are very small. The less ancient, extinct creatures in the last hundred years, such as wolves, their chances of being successfully cloned are greater, but if the genes of the cloned individuals all come from a donor, then it is difficult for them to reproduce properly.

Cloning technology, used in those endangered, but not completely extinct animals is a little more valuable, as mentioned before the black-footed ferret general, is used to increase the genetic diversity of these animals. It is better to protect the existing endangered animals on the ground than to spend time and effort to "revive" ancient creatures.