In a move right out of Jurassic Park, a cloned Przewalski’s horse has been born using genetic material cryopreserved 40 years ago, reviving genetic diversity “lost” decades ago. Kurt, the adorable colt, is the most genetically important member of his dwindling species. The last time the Przewalski’s horse was seen in the wild was in 1969. Some of the horses remained in zoos but the captive breeding program that founded current the Przewalski population comes from just 12 horses — 11 Przewalski’s horses caught in the wild between 1899 and 1902 and another caught in 1947. While there are about 2,000 horses today, that genetic pool is a pretty shallow puddle.
Those 12 ancestor individuals represent what is known as a population bottleneck. With so little variation among the surviving horses, the species is subject to “genetic drift”, when random genetic elements in a population become more pronounced and a higher chance of inbreeding, which can reduce the chance of long-term survival by spreading unwanted traits through the population,
Kurt was cloned from the genetic material of a Przewalski’s horse named Kuporovic, who lived from 1975 to 1998. An analysis of the captive breeding pedigree revealed that Kuporovic’s genome had unique ancestry from two wild founders. This meant he offered significantly more genetic variation than any of his living relatives, so in 1980, scientists took a sample and preserved it in San Diego Zoo’s Frozen Zoo. Kurt’s successful birth is especially important as he is the first animal to be cloned from genetic material that was stored for this long. The oldest genetic material previously used was to breed black-footed ferrets with sperm frozen for 20 years; bulls have also been cloned from materials frozen 13 years ago. Kurt demonstrates the long-term viability of preserved genetic material, opening the way to save other endangered species.
Kurt is the first successfully cloned Przewalski’s horse and his birth gives hope to other species that are endangered. His birth is part of a partnership between Revive & Restore, a wildlife conservation organization that promotes biotechnologies, the San Diego Zoo Global and ViaGen Equine, a pet cloning company. The colt is named in honor of Kurt Benirschke, who was instrumental in founding the Frozen Zoo and the conservation program at San Diego Zoo Global.
When he matures, Kurt will move to the San Diego Zoo Safari Park where he can be integrated into their herd’s breeding program. In the meantime, he’s a bundle of foal cuteness who has no idea of his special status in the world.
Next step? Woolly Mammoths!