After 40 years of deep DNA freezing, scientists cloned a disappearing horse breed

Scientists at San Diego Zoo are restoring horse cells after 40 years of deep freeze to clone an endangered species. This is reported by The San Diego Union-Tribune.

Kurt’s two-month-old colt looks and behaves like any other young horse. However, it is Przewalski’s horse, a species that used to be extinct in the wild and is still endangered in Central Asia. There are only about 2000 animals left on the planet.

San Diego Zoo has high hopes that Kurt will help change the situation for his species. It was cloned from stallion skin cells taken in 1980 and stored in Frozen Zoo, an extensive repository of 10,000 cell lines of more than 1,100 species and subspecies at San Diego Zoo Global.

San Diego Zoo Global is a non-profit organization that manages the Zoo of the same name, the Safari Park, the Zoo Conservation Research Institute, and the Global Zoo Wildlife Conservation.

In this way, scientists hope to regain some of the gene pool that would otherwise be lost,” explains Oliver Ryder, Director of Genetics at San Diego Zoo Global.

This is the first time anyone has successfully cloned Przewalski’s horse. Each living horse is associated with 12 wild ancestors. This does not bode well for any of these species, as it requires genetic diversity to adapt to changes in habitat and fight new diseases.

The researchers were happy to find a stallion with DNA fragments that were largely missing from the rest of its species.

The ancestors of this particular stallion did not breed to the same extent as other Przewalski horses, so it had rare DNA fragments that would have been lost forever if they had not been preserved.

For 40 years, the stallion cells were kept frozen at minus 160 °C – colder than the evening on the planet Mercury. Now the researchers have revitalized the cells and connected one of them to an unfertilized egg of a domesticated horse. Since the scientists removed the core of the egg, which contains the DNA of the mother horse, almost all the genetic material was obtained from the stallion.

Then the team transplanted the egg back inside the horse, which acted as a surrogate mother. This is the same method that was widely used to clone Dolly’s sheep in 1996 and has since been used to clone cattle, cats, deer and horses as well as other species.

Kurt was born on August 6 in the Texas Veterinary Center. The scientists’ plan is to eventually bring Kurt to Safari Park, where he will join Przewalski’s 14 horses in the park as part of a conservation and breeding program.