Two Ferrets Successfully Cloned From Frozen DNA Sample Taken in 1988; Can This Process Save Other Species From Extinction?

A species of mammals on the verge of extinction has a promising future after experts cloned an animal frozen in time almost four decades ago.

Repopulating the Ferrets

On April 17, the U.S. Fish and Wildlife Service (FWS) announced the births last year of Noreen and Antonia, two baby ferrets cloned from cells frozen since the 1980s. The authorities hope the animals will breed when they reach full maturity later this year.

The ferrets, named Antonis and Noreen, are seen as the much-needed solution to the survival of their species which has dwindled to just 300 in the wild. They were the second and third black-footed ferrets to be cloned last May after Elizabeth Ann in 2021. Due to a reproductive organ issue, Elizabeth Ann's only litter was not viable for breeding.

The Fish and Wildlife Service has not announced plans to clone more black-footed ferrets, claiming they are focusing on ensuring Antonia and Noreen are healthy. Scientists try to breed from them but don't intend to clone other endangered animals yet.

The population decline of the black-footed ferret was so dramatic that they were thought to be extinct in the early 1970s. However, seven left were discovered in the wilderness after a decade when a dog brought a dead black-footed ferret home.

How Did the Cloning Process Take Place?

The cloning process used to create Antonia and Noreen is similar to the one used on Dolly the Sheep in 1996. In this method, scientists inject DNA cells from a donor animal into an egg cell.

Antonia and Noreen were bred from frozen tissue samples collected in 1988 from a black-footed ferret named Willa. The samples were stored at the Frozen Zoo of San Diego's Zoo Wildlife Alliance. The animals were cloned by taking one of Willa's cells and injecting it into an egg from a domesticated ferret.

The process, called somatic cell cloning, requires removing DNA tissue from a donor cell and replacing the DNA in an egg cell. Experts then implant the altered egg into a surrogate of the same species. When the animal is born, it is genetically identical to the donor DNA it came from.

Willa did not have any living descendants, so scientists hope that freezing some of her cells could reproduce the ferret population in the future. The samples were saved because they contained three times more unique genetic variations than the current population, making them ideal for cloning.

Genetic variety is essential for cloning because it helps the species adapt and survive in the wild. It also makes them adverse to disease outbreaks and environmental changes in the future.

Inbreeding occurs in small animal populations like the black-footed ferret. It is seen as a factor that can reduce the species' ability to reproduce and survive in the wild. According to the Fish and Wildlife Service, black-footed ferrets have only seven genetic founders, a concern in the captive breeding program.

Geneticist Dr. Marty Kardos from NOAA's Northwest Fisheries Science Center explained that small populations and low genetic diversity are problematic since they make populations more vulnerable to extinction.