Last year, Ben Novak drove across the country to spend New Year’s Eve with a black-footed ferret. Elizabeth Ann had just turned 21 days – a milestone for any ferret, but a particularly significant one for Elizabeth Ann, the first native, endangered species in North America to be cloned.
Mr. Novak, the senior scientist of the nonprofit biotechnology Revive & Restore, bought a motor home to drive his wife and identical North Carolina twins to the National Black-footed Ferret Conservation Center near Fort Collins, Colorado. (They made a pit stop in Texas to see Kurt, the first cloned Przewalski horse.)
Mr. Novak spent less than 15 minutes with Elizabeth Ann, her black mask, feet and tail just showing through her fluffy white fur. “It felt like time stood still,” said Novak.
Fortunately, time didn’t stand still for Elizabeth Ann, who now looks taller, tan and a lot more like a ferret. Your successful cloning is the result of years of collaboration with the US fish and wildlife service Revive & Restore, the non-profit company ViaGen Pets & Equine, the San Diego Zoo Global and the Association of Zoos and Aquariums.
Cloned siblings are on their way and potential (cloned) partners are already waiting. If successful, the project could give endangered species the necessary genetic diversity. And it’s another promising advance in the broader effort to use cloning to remove ever-increasing numbers from extinction.
The black-footed ferret, the first species to be reintroduced into previous habitats using artificial insemination, has long been a model species for new conservation technologies. Hence, it is appropriate that the ferrets are the second species cloned for this type of genetic rescue. (Elizabeth Ann follows in the footsteps of Kurt the horse.)
“Pinch me,” joked Oliver Ryder, the director of conservation genetics at San Diego Zoo Global, over a Zoom call. “This animal’s cells from 1988 have become an animal.”
In the early 1900s, black-footed ferrets dug across the American West, according to Pete Gober, the National Fish and Wildlife Service coordinator for black-footed ferret restoration. But the ferrets disappeared after their main source of food, the prairie dogs, was nearly wiped out by poisoning, plague, and habitat loss. “We thought they were gone,” said Dr. Gober.
The species was thought to be extinct in the wild until 1981 when a ranch dog named Shep dropped a dead black-footed ferret on a porch near Meeteetse, Wyo. The rancher’s wife took the dead ferret to a local taxidermist, who realized it was a newly killed extinct species in hand, and alerted the Wyoming Game and Fish Department.
The newly discovered population flourished for a few years, but was nearly wiped out by distemper and sylvate, a disease of the same bacterium that causes bubonic plague in humans. The Fish and Wildlife Service caught the remaining 18 ferrets, but only seven passed their genes, leaving a population of limited genetic diversity susceptible to inbreeding pathogens or health disorders. All black-footed ferrets living today are essentially half-siblings – with the exception of Elizabeth Ann.
The path to cloning a black-footed ferret began in the 1980s at a conference on conservation biology. Dr. Ryder, the geneticist at the San Diego Zoo, happened to be sitting at a banquet table with Tom Thorne, who worked in the Wyoming Game and Fish Department. Dr. Ryder seized the moment and asked Dr. Thorne asked whether he would consider sending black-footed ferret skin biopsies to the Frozen Zoo, a growing collection of cryopreserved samples of animal tissue. “I told him we didn’t see what it could be used for,” said Dr. Ryder. “I don’t remember a resounding yes.”
On October 23, 1985, Dr. Ryder unexpectedly received a box from Wyoming. “Well, hot dog, we have black-footed ferrets,” he recalled.
Dr. Ryder’s laboratory received additional samples in 1988, one from a ferret named Willa that was caught in the wild. Willa had offspring, but they had died; For black-footed ferrets, it was full of potential genetic diversity. The Frozen Zoo established a cell culture from Willa and stored it in their huge freezer, which houses the cells of 1,100 different animal species such as an extinct Hawaiian honey herb and the highly endangered vaquita, a porpoise species, at minus 320 degrees Fahrenheit.
In 2013, the Fish and Wildlife Service reached out to Revive & Restore to investigate how the biotechnology the nonprofit is developing to address species extinction can help increase the genetic diversity of black-footed ferrets. The following year Revive & Restore sequenced the genomes of four black-footed ferrets.
First there was Balboa, who was born through artificial insemination with cryopreserved, genetically diverse sperm. Second was Cheerio, who was naturally born and shares the lineage of all seven founders. Novak calls him “every ferret”. The last two ferrets came from tissue samples in the Frozen Zoo, a male named “Studbook Number 2” and a female named Willa. “When we looked at Balboa, we found empirically that much of the genetic diversity was saved by going back in time,” Novak said.
Revive & Restore drafted a proposal and submitted it to Fish and Wildlife. In 2018, the nonprofit received its first approval to research cloning of an endangered species. Revive & Restore has partnered with commercial cloning company ViaGen Pets & Equine to design the cloning process.
The first trial started around Halloween. The Frozen Zoo sent Willa’s cryogenically preserved cell line to ViaGen’s lab in New York. ViaGen created embryos and implanted them in a domestic ferret surrogate. On day 14, an ultrasound confirmed the heartbeat.
The surrogate mother was taken to the conservation center and monitored for signs of labor 24 hours a day. On December 10th, Elizabeth Ann was delivered by caesarean section. “Our lovely little clone,” said Mr Novak.
On Elizabeth Ann’s 65th day of life, the technicians drew her blood, wiped her cheek, and sent the samples to Samantha Wisely, a conservation geneticist at the University of Florida, who confirmed that Elizabeth Ann was indeed a black-footed ferret.
Elizabeth Ann will spend her days at the Conservation Center, with sisters (other clones of Willa) and potential companions (clones from stud book number 2) coming soon. Researchers will monitor their health and watch them grow and hop around in the artificial burrows in their cages, said Dr. Gober. When the clones reach sexual maturity, they are bred and their offspring are back-bred with wild black-footed ferrets to ensure that no mitochondrial DNA is left from the surrogate mother.
“It will be a slow, methodical process,” said Dr. Wisely working on a paper on the bioethics of species cloning. “It is imperative that we ensure that we do not compromise the genetic lineage of black-footed ferrets by introducing this individual.”
The pandemic could slow things down, said Dr. Ryder. However, if everything goes according to plan, the clone’s diverse genome could help protect black-footed ferrets from their own pandemics: not only distemper and Sylvatian plague, but also SARS-CoV-2, which is highly contagious in minks and close relatives of ferrets. In the fall, 120 black-footed ferrets received an experimental Covid-19 vaccine.
Revive & Restore is still working on its Moonshot projects which include the resuscitation of the passenger pigeon and the woolly mammoth. Restoring these more quixotic species would be a much more expensive, complicated, and controversial endeavor. Some conservationists argue that funding extinction would waste resources in an underfunded area amid an accelerated extinction crisis. In Mr. Novak’s eyes, any technology that could help bring a mammoth back to life is technology that could help restore species that are already endangered.
In the Frozen Zoo, the cells of long dead creatures wait for their moment to come back to life in a certain way. “If the technologies are developed in the future but no one has saved cells, it would be a missed opportunity,” said Dr. Ryder. “The time to save these cells is now.” Dr. Ryder’s lab has already regrown and re-frozen more of Willa’s cells, replacing the cells that became Elizabeth Ann.