San Diego’s “Frozen Zoo” Clones Endangered Horse

Forty years ago, scientists took DNA from the endangered Przewalski’s horse and stored it in the Global Frozen Zoo—a futuristic “cryobank” that had just been set up at San Diego Zoo.

This frozen zoo collects living cell cultures from thousands of creatures, which it then grows in the lab and stores in liquid nitrogen, at a staggering -196 degrees Celsius.

There the Przewalski’s tissue stayed, alongside frozen cheetah sperm, southern white rhino oocytes, and DNA from two-toed sloths and African elephants, until it was brought out for a cloning experiment.

And on 6 August 2020, the first successfully cloned Przewalski’s horse was born—a genetic replica of a horse that was born in the UK in 1975 and lived in the US from 1978 until its death in 1998.

 

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?: San Diego Zoo Global ? New baby alert! ? This energetic little foal is a #Przewalski’s horse, a rare horse native to central Asia. There’s something else that’s special about him … he’s a clone! In fact, he’s the first successfully cloned Przewalski’s horse in the world, the zoo said. ⠀ ⠀ ? The foal, born to a domestic surrogate mother, is a clone of a male Przewalski’s horse whose DNA was cryopreserved 40 years ago at the #SanDiegoZoo Global Frozen Zoo. ⠀ ⠀ The baby was birthed in #Texas at Timber Creek Veterinary but will be moved to the @sdzsafaripark when he’s older. There, he’ll be integrated into a breeding herd of his species to help with the horses’ conservation. ⠀ ⠀ The Przewalski’s horse has survived for the past 40 years mostly in zoos, and all of the surviving horses are related to 12 wild Przewalski’s horses. Formerly extinct in the wild, there’s been efforts to establish wild herds in their native China and Mongolia. ⠀ .⠀ .⠀ .⠀ #conservationbiology #wildlifeconservation #przewalskihorse #sandiegozoosafaripark #horse

A post shared by KPBS (@kpbs) on Sep 5, 2020 at 12:00pm PDT

While the science behind the cloning is interesting, what’s most important for conservationists is the ability to diversify the genetics of the current stock of Przewalski’s horses. Most of the species are found in zoos, and every single one of the surviving horses is related to 12 wild horses from the zoos.

For many, the horse species, which has never been domesticated, is the only ‘true’ wild horse in the world.

An Instagram post from San Diego Zoo shows the little horse, which was born at Timber Creek Veterinary in Texas, running and jumping around a pen.

In China and Mongolia, there have been various programmes to reintroduce the horse into the wild, which have successfully grown populations—the remaining issue being the lack of genetic diversity.