Cloned Black-Footed Ferret Revives Genetic Diversity From Frozen 1980s Cells

In late September 1981, a ranch dog in Meeteetse, Wyoming named Shep caught something in the night. By morning it was dead beside his food bowl. John Hogg looked at it, figured it was probably a mink, and tossed it into the weeds along the river.

His wife Lucille fished it back out. She wanted it mounted.

The taxidermist recognized it immediately. It was a black-footed ferret, a species many scientists believed had disappeared. The last known captive animals had died a couple of years earlier. Wildlife biologists descended on Meeteetse and found a small wild colony nearby.

For a few years, the ferret had a second chance.

Then disease struck. Canine distemper swept through the population, and plague devastated the prairie dog colonies the ferrets depended on for food. By 1987 the species was collapsing. Scientists scrambled to capture every remaining ferret before the last wild population vanished.

Eighteen ferrets became the founders of the captive breeding program. Only seven successfully produced offspring. Every black-footed ferret alive today traces its ancestry back to those seven individuals.

One of the eighteen, a female named Willa, never reproduced. She died in January 1988. But tissue from Willa had been sent to the San Diego Zoo's Frozen Zoo, a cryogenic library preserving cells from more than a thousand species. Her genes were absent from the breeding population, and someone had the foresight to save them anyway.

For more than three decades, no one knew whether those cells would ever matter. Then they figured out what to do with them.

In December 2020, a cloned black-footed ferret named Elizabeth Ann was born from Willa's frozen cells, carried by a domestic ferret surrogate. She became the first cloned endangered species native to the United States.

Willa's genome contains nearly three times the unique genetic variation found in the average living ferret. Elizabeth Ann isn't just a scientific curiosity. She represents a potential lifeline for a population so inbred that nearly every animal is related.

The species got a second chance twice.

First from a ranch dog that caught something in the dark and a woman who didn't want to throw it away.

Then from the decision to freeze the cells of a ferret that had never had offspring, on the chance that someone, someday, might need them.