A foal has been cloned from a stallion who died decades ago, in hope this species will not become extinct. H&H finds out why increasing genetic diversity is essential for survival and what this technology could mean...
THE birth of a Przewalski’s horse as a way of re-introducing diversity into the species’ gene pool is an example of the way cloning can benefit conservation and prevent extinction, experts believe.
Kurt, the first successfully cloned endangered Przewalski’s horse, was born in Texas, US, on 6 August. He is the clone of a “genetically important” UK-born stallion, cells from whom had been stored at the San Diego Zoo’s “frozen zoo” tissue bank since 1980.
Revive & Restore, which promotes the use of biotechnology in conservation, worked with the zoo and cloning firm ViaGen Equine on the project.
Co-founder Ryan Phelan told H&H the aim is to preserve the Przewalski’s horse, a separate species of which some 2,000 individuals survive, from 12 rescued from extinction early last century.
“We’ve gone back at least 40 years to create greater genetic diversity; it’s as if all the inbreeding of that time can be reset,” she said. “The hope is that this foal will become a breeding stallion and can contribute to the population.”
Tullis Matson of Stallion AI Services, which has worked with ViaGen in the past, explained that inbreeding and a lack of genetic diversity are what lead to extinction.
“It’s not always lack of numbers,” he told H&H. “It’s the inbreeding coefficient.
“Inbreeding can lead to issues such as lack of fertility, poorer-quality semen, high neo-natal deaths; it’s called the extinction vortex, and the breed disappears in front of you.
“Bringing a new line in like this can save a breed or species from extinction. What’s happened here is absolutely brilliant.”
Mr Matson said his work with preserving rare UK horse breeds has included freezing semen and sexed foals, but “we’ve got to look at all different methods for preserving these animals”, and some UK equine conservation bodies are now looking at cloning in the fight for survival.
He believes this project is overwhelmingly positive for conservation, of all species, despite the fact “cloning” has been seen by some as a “dirty word”.
“This puts the message out, that cloning can really help, especially with rare breeds, and stop species from going extinct,” he said. “We as a species are pretty much devastating our planet and even if we can’t reverse it, we’ve got to find ways of slowing it down.”
Ms Phelan agreed, adding that it will depend on how successful a breeding stallion Kurt is but the hope is for him to bring back extinct alleles, forms of genes, which could help make the species healthier, and improve fertility and resistance to disease, for example.
“These are the typical problems with the genetic bottleneck,” she said.
“The concept of ‘interfering’ in nature is discussed, and whether we should let it take its course, but if we do that, many species go extinct.”
Ms Phelan added that the foal is named after Kurt Benirschke, a geneticist at the zoo who had the idea of preserving the important genetic material before it was lost, decades before the technology to use it existed.
“It’s fitting we’ve named the foal after him,” she said.
World Horse Welfare CEO Roly Owers told H&H the charity takes a “very cautious view” of cloning.
“We have serious concerns regarding the health and welfare of cloned animals,” he said. “There is still a lack of scientific evidence to show that cloning of equines is safe. We fully recognise the challenges faced in preserving rare breeds such as the Przewalski’s horses, but the techniques used to do so have to safeguard equine welfare and we do not believe this can be said for cloning at the moment.”
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