Last year, Ben Novak crossed the country to spend New Years Eve with a black-footed ferret. Elizabeth Ann was just 21 days old – surely a milestone for any ferret, but a particularly significant milestone for Elizabeth Ann, the first endangered animal species in North America to be cloned.
Mr Novak, the senior scientist at biotech nonprofit Revive & Restore, bought a trailer to drive his wife and identical twin children from North Carolina to the National Black-footed Ferret Conservation Center near Fort Collins , Colorado (They made a pit stop in Texas to see Kurt, Przewalski’s first cloned horse.)
Mr Novak spent less than 15 minutes with Elizabeth Ann, whose black mask, feet and tail were just beginning to show through her fluffy white fur. “It was as if time had stood still,” Mr. Novak said.
Fortunately, time has not stood still for Elizabeth Ann, who now looks fatter, darker and much more like a ferret. Its successful cloning is the culmination of a multi-year collaboration with the US Fish and Wildlife Service, Revive & Restore, for-profit company ViaGen Pets & Equine, the San Diego Global Zoo, and the Association of Zoos and Aquariums. .
Cloned siblings are on the way and potential (cloned) partners are already lined up. If successful, the project could provide the genetic diversity necessary for threatened species. And it marks another promising step forward in the broader effort to use cloning to recover ever-growing numbers of species on the brink of extinction.
The blacklegged ferret, the first species to be reintroduced into ancient habitats using artificial insemination, has long been a model species for new conservation technologies. It is therefore fitting that ferrets have become the second species to be cloned for this type of genetic rescue. (Elizabeth Ann follows in Kurt the horse’s footsteps.)
“Pinch me,” joked Oliver Ryder, director of conservation genetics at the San Diego Global Zoo, during a Zoom call. “The cells of this animal banked in 1988 became an animal.”
In the early 1900s, black-footed ferrets dug all over the American West, according to Pete Gober, the Fish and Wildlife Service’s national black-footed ferret recovery coordinator. But ferrets became extinct after their main food source, prairie dogs, was nearly wiped out by poisoning, plague and loss of habitat. “We thought they were gone,” Dr Gober said.
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 breeder’s wife took the dead ferret to a local taxidermist, who realized he was holding a freshly killed extinct species and alerted the Wyoming Game and Fish Department.
The newly discovered population thrived for a few years but was nearly extinguished by distemper and sylvatic plague, a disease of the same bacteria that causes bubonic plague in humans. The Fish and Wildlife Service captured the remaining 18 ferrets, but only seven passed on their genes, leaving behind a population with limited genetic diversity that is vulnerable to pathogens or health disorders caused by inbreeding. All black-footed ferrets alive 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, sat at a banquet table with Tom Thorne, who worked at the Wyoming Game and Fish Department. Seizing the moment, Dr Ryder asked Dr Thorne if he was considering sending skin biopsies of blacklegged ferrets to the frozen zoo, a growing collection of cryopreserved animal tissue samples. “I told him we didn’t know what they could be used for,” Dr. Ryder said. “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 ferret individuals,” he recalls, saying.
Dr Ryder’s lab received more samples in 1988, one from a ferret named Willa that was captured in the wild. Willa had offspring but they were dead; by black-footed ferret standards, she was overflowing with potential genetic diversity. The Frozen Zoo established a cell culture from Willa and stored it in its massive freezer, which cradles the cells of 1,100 different species of animals, including an extinct Hawaiian creeper and the vaquita, a highly endangered species of porpoise. , at minus 320 degrees Fahrenheit.
In 2013, the Fish and Wildlife Service approached Revive & Restore to explore how biotechnology, which the nonprofit is developing to combat species extinction, could help increase the genetic diversity of blacklegged ferrets. The following year, Revive & Restore sequenced the genomes of four blacklegged ferrets.
First there was Balboa, born by artificial insemination using cryopreserved and genetically diverse sperm. The second was Cheerio, who was born naturally and shares the ancestry of the Seven Founders; Novak calls it an “all ferrets”. The last two ferrets were from tissue samples at the Frozen Zoo, a male named “Studbook number 2” and a female named Willa. “When we looked at Balboa, we saw empirically that much of the genetic diversity had been saved going back in time,” Mr. Novak said.
Revive & Restore designed a proposal and submitted it to Fish and Wildlife. In 2018, the non-profit organization received the very first research permit into the cloning of an endangered species. Revive & Restore has partnered with the commercial cloning company ViaGen Pets & Equine to design the cloning process.
The first trial started around Halloween. The Frozen Zoo sent Willa’s cryogenic cell line to ViaGen’s lab in New York City. ViaGen created embryos and implanted them in a domestic ferret surrogate. On day 14, an ultrasound confirmed the heartbeat.
The surrogate was rushed to the conservation center and was monitored around the clock for signs of labor. On December 10, Elizabeth Ann was delivered by Caesarean. “Our beautiful little clone,” Mr. Novak said.
On the 65th day of Elizabeth Ann’s life, technicians drew her blood, rubbed her cheek, and sent the samples to Samantha Wisdom, a conservation geneticist at the University of Florida, who confirmed that Elizabeth Ann was actually a black-footed ferret.
Elizabeth Ann will live out her days at the Conservation Center, soon joined by sisters (other Willa clones) and potential mates (Studbook number 2 clones). Researchers will monitor their health and watch them grow and roam the artificial burrows inside their cages, Dr Gober said. When the clones reach sexual maturity, they will reproduce, and then their offspring will be mated with wild black-legged ferrets to ensure that no more mitochondrial DNA remains from the surrogate mother.
“It will be a slow and methodical process,” said Dr Wisdom, who is working on an article on the bioethics of cloning the species. “We have to make absolutely sure that we do not endanger the genetic line of blacklegged ferrets by presenting this individual.”
The pandemic could slow things down, Dr Ryder said. But if all goes according to plan, the clone’s diverse genome could help protect blacklegged ferrets from their own pandemics: not only distemper and sylvatic plague, but also SARS-CoV-2, which is very contagious in mink, close relatives. ferrets. In the fall, 120 blacklegged ferrets received an experimental Covid-19 vaccine.
Revive & Restore is still working on its moonshot projects, which include the resurrection of the passenger pigeon and the woolly mammoth. Restoring these more chimerical species would be a much more expensive, complicated, and controversial endeavor. Some conservationists argue that funding de-extinction would waste resources in an underfunded area amid an accelerated extinction crisis. In Novak’s eyes, any technology that could help bring a mammoth back to life is technology that could aid in the recovery of already endangered species.
In the frozen zoo, the cells of long-dead creatures are biding their time to come to life, as it were. “If the technologies are developed in the future but no one has saved any cells, this would be an opportunity that would be lost,” said Dr Ryder. “The time has come to save these cells.” Dr. Ryder’s lab has already regrown and refrozen other Willa cells, replacing the ones that became Elizabeth Ann.