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    Can frozen DNA help species survive extinction? San Diego’s Frozen Zoo, conservationists partner to put biodiversity banking on the map
    • October 16, 2023

    Emily Alvarenga | The San Diego Union-Tribune

    For nearly half a century, the San Diego Zoo Wildlife Alliance has been taking the fantasy world of “Jurassic Park” from fiction to reality — minus the dinosaurs and destruction.

    As wildlife populations plummet and biodiversity is lost worldwide, the alliance has been working to collect and preserve genetic samples, taken during routine exams or after animals have died, from as many species as it can with what it calls its Frozen Zoo.

    Now its conservation efforts are being recognized globally, as it was designated Wednesday by a major conservation group as its first-ever center focusing on gene banking to help rare and endangered species survive.

    The Species Survival Commission of the International Union for Conservation of Nature — the world’s largest conservation organization — has partnered with the wildlife alliance to form the union’s newest Center for Species Survival.

    It will be one of the organization’s just 17 such centers around the world and the only one to focus on a specific strategy to prevent species extinction, such as biodiversity banking, rather than on a particular species or environment.

    The announcement is an indicator of the San Diego Zoo Wildlife Alliance’s progress in gene banking and the promise of its efforts in helping endangered wildlife survive through reproductive assistance, stem cell therapy and cloning.

    In recent years, it has led to advances scientists hope could make cloning viable enough to help restore wildlife species — provided they prove capable of successfully breeding.

    Escondido, CA, October 11, 2023: Fibroblast cells of a black-footed ferret, which are used for cloning are shown at the San Diego Zoo Wildlife Alliance’s Wildlife Biodiversity Bank Frozen Zoo on Wednesday, October 11, 2023 in Escondido, CA. The cryobank at the Frozen Zoo holds thousands of types of individual animals. (K.C. Alfred / The San Diego Union-Tribune)

    While there are “Jurassic Park” connections — the art director of Steven Spielberg’s film found inspiration from the Frozen Zoo and from the Safari Park’s entry gates — that work isn’t the stuff of science fiction.

    Biodiversity banking, or biobanking, refers to the process of preserving living cells, tissue, eggs or sperm, seeds and other biomaterials. Those genetic materials are carefully frozen in liquid nitrogen so they can be studied and used for years to come.

    “This loss of genetic diversity is our fault — it’s because of our actions — so we are actually resolving an ethical problem,” said Barbara Durrant, director of reproductive sciences at the San Diego Zoo Wildlife Alliance.

    The survival of the northern white rhinoceros and dozens of other species could hinge on these preserved cells amassed in the last nearly 50 years, according to the organization’s researchers.

    The local collection has become the largest and most diverse of its kind. To date, the Frozen Zoo contains nearly 11,000 living cell cultures representing about 1,280 different species and subspecies of rare and endangered animals.

    Biodiversity banking not only preserves unrecoverable genetic diversity in wildlife species — potentially giving them better chances at withstanding environmental factors — but also expands the capacity for genetic research and rescue, making “an everlasting contribution to conservation,” Durrant explained.

    “These cells should be here long after you and I are gone,” said Marlys Houck, curator of the Frozen Zoo.

    Escondido, CA, October 11, 2023: Kurt, the world’s first cloned Przewalski’s horse eats carrots and apples at the San Diego Zoo Safari Park on Wednesday, October 11, 2023 in Escondido, CA. (K.C. Alfred / The San Diego Union-Tribune)

    Locally, a cloned Przewalski’s horse named Kurt born in August 2020 was among the first genetic milestones in the alliance’s efforts to help restore endangered animal populations.

    He’s the world’s first successfully cloned Przewalski’s horse, a breed native to Mongolia and formerly extinct in the wild. They were reintroduced to their natural habitat in recent years and are now the only true wild horse left in the world.

    Named for Kurt Benirschke, who founded the Frozen Zoo, the horse was cloned from skin cells taken from a stallion in 1980 and cryogenically safeguarded.

    Now 3 years old, scientists hope Kurt can soon start helping to further safeguard his species by joining the herd of Przewalski’s horses at the park as part of a conservation and breeding program.

    But before that can happen, Kurt has to learn how to be a wild horse. He’s spent the last year doing so in the Safari Park’s Central Asia field habitat alongside Holly, a female Przewalski’s who’s just a few months older.

    Though not always easy — it includes some kicks to the face — learning the behavioral language will help him secure his place in the herd.

    Just last month, the world’s second cloned Przewalski’s horse, Ollie — a genetic twin of Kurt’s made from the same stallion’s DNA — arrived at the Safari Park, marking the first time any endangered animal has been cloned more than once.

    Ollie — named after Oliver Ryder, the alliance’s director of conservation genetics — and Kurt will eventually be reunited at the Safari Park.

    Scientists were also able to clone an endangered black-footed ferret in 2020 using genetic material from the Frozen Zoo.

    But Durrant says these animals are just the beginning.

    “It’s huge because it shows that the technology works, that we can actually recreate animals from the Frozen Zoo,” she said. “Once those cells are frozen, they’re still living … But theoretically, we can have them for centuries. So all the genetic diversity that we have, we can then slowly reintroduce into populations.”

    Scientists are currently working on DNA analysis and genome sequencing for a dozen cryo-preserved northern white rhinoceros cultures from 12 different animals in the Frozen Zoo after the last male of the subspecies died in 2018, leaving only two females left in a Kenyan conservancy.

    The hope is the species could be revived one day.

    The Frozen Zoo is part of the San Diego Zoo Wildlife Alliance’s Wildlife Biodiversity Bank, which safeguards living and nonliving materials in a handful of collections.

    Escondido, CA, October 11, 2023: Postdoctoral research associate Joe Ree holds coastal sage scrub oak seedlings in the San Diego Zoo Wildlife Alliance’s Native Plant Gene Bank on Wednesday, October 11, 2023 in Escondido, CA. (K.C. Alfred / The San Diego Union-Tribune)

    Also among them is the Native Plant Gene Bank, which is working locally to conserve the diversity of San Diego County’s flora by drying and freezing seeds for long-term storage.

    The conservation team has been working to collect various species of plants from the 900-acre, undeveloped biodiversity reserve that sits behind the Safari Park.

    Along with seeds, scientists are also researching ways to cultivate plants from tissue culture in laboratory conditions away from threats they would normally face in the wild. Those plants will be cryogenically frozen so they could one day replenish areas that are decimated.

    The San Diego Zoo Wildlife Alliance’s new distinction as a global center for biodiversity banking will help it collaborate with a global network of partners and train and advise other zoos in their own such efforts.

    “It’s very gratifying,” Durrant said. “It highlights our work. And it lets the rest of the conservation community know that we are someone that they can come to. That’s how we get this job done. We can’t do it by ourselves.”

    More important, Durrant says the new global center could emulate “Jurassic Park” scientists by helping to bring species back from extinction — while also preserving diversity well beyond fantasy.

    ​ Orange County Register