What Is Animal Cloning? Black-Footed Ferret Is U.S.' First Duplicated Endangered Species

An endangered species of ferret native to North America's Great Plains is being brought back from the brink of extinction by cloning, experts say.

Researchers aiming to boost the population of the black-footed ferret made progress on December 10 last year with the birth of Elizabeth Ann—created from the frozen cells of another member of her species, called Willa, that lived about three decades ago.

Elizabeth Ann, the first cloned black-footed ferret, was 71 days old as of Friday. Its birth marked the first cloning of a native U.S. endangered species.

The U.S. Fish and Wildlife Service released multiple images and a video of the ferret to Twitter on Thursday, showing the cloned animal at 48 days old, the ferret with its surrogate mother and the clone eating its first prairie dog.

Before Elizabeth Ann, all black-footed ferrets—part of a captive breeding program—had been descended from seven individuals, which posed "genetic challenges."

Researchers said the efforts were focused on using cloning to introduce more genetic diversity into the species and help to build up "disease resilience barriers."

While the duplicate will not be released into the wild, cloning could eventually support habitat conservation and the reestablishment of additional populations in the wild.

Without genetic diversity, the species will become more likely to contract diseases and abnormalities, alongside decreased fertility rate. Willa, with no living descendants, was among the last of its kind to be captured and was not one of the seven ancestors.

The Wyoming Game & Fish Department preserved Willa's genes, and its tissue samples were transferred to San Diego Zoo Global's Frozen Zoo in 1988.

A recent genomic study suggested that Willa's genome contained "three times more unique variations than the living population," the Fish and Wildlife Service said.

That means that if Elizabeth Ann successfully mates and reproduces, she could provide unique genetic diversity into the species—massively helping conservation efforts.

Animal cloning, explained

The National Human Genome Research Institute (NHGRI) explains on its website that there are three different types of artificial cloning: gene, reproductive and therapeutic.

In reproductive cloning, which is how animals are cloned, researchers "remove a mature somatic cell, such as a skin cell, from an animal that they wish to copy."

DNA of the donor animal's somatic cell is transferred into an egg cell that has had its DNA-containing nucleus removed—either by injecting it into the empty egg or by using an electrical current to fuse the entire somatic cell with the empty egg.

Whatever the process, the egg is then allowed to develop into an early-stage embryo in a test-tube before it is implanted into the womb of an adult female animal, which later gives birth to "an animal that has the same genetic makeup as the animal that donated the somatic cell." That young animal, the NHGRI says, is known as a clone.

Scientists have used the process to clone a variety of animals over the past 50 years, including cats, deer, horses, rabbits, rats, cattle, sheep and a rhesus monkey.

The first-ever genetically identical mice were produced in 1979. A more famous breakthrough came in 1996 when a team successfully cloned the first mammal using a somatic cell from a 6-year-old sheep. The clone was known as Dolly.

While cloning is often used in science fiction tales, experts from the U.S. Food and Drug Administration (FDA) say the process is not new, and is also used for plants.

It explains in a fact-sheet: "Much of the public perception of cloning likely comes from science fiction books and movies. Some people incorrectly believe that clones spring forth fully formed, or are grown in test tubes. This is just not the case.

"Clones are born just like other animals. They are similar to identical twins, only born at different times. Just as twins share the same DNA, clones have the same genes as the donor animal. A clone is not a mutant, nor is it a weaker version of the original animal."