The Frozen Zoo: Noah’s Ark for an Era of Genomic Tools and Rampant Extinction

May 12, 2019

Leona Chemnick, Marlys Houck, and Dr. Oliver Ryder in The Frozen Zoo - a collection of cell and tissue samples at San Diego Zoo's Institute for Conservation Research.
Credit Photo courtesy of San Diego Zoo Global

Headlines trumpeted the dire news: a new U.N. report says human beings have put one million species at risk of extinction within decades. They point the finger at five major culprits – habitat destruction, exploitation, invasive species, pollution, and climate change.

Researchers at San Diego Zoo’s Institute for Conservation Research are fighting back with what they call The Frozen Zoo. It’s a collection of frozen cell and tissue samples that might be used to bolster failing populations of endangered species.

Oliver Ryder, director of conservation genetics, compares it to Noah’s Ark, updated with the knowledge and tools of modern genetics and genomics.

“We know that we wouldn't be able to restore populations from two-by-twos,” he said. “But the idea of bridging between the present and the future, at a time when species are going to decline, that's very much in line with the biblical story.”

At the heart of The Frozen Zoo has always been the idea of giving future conservation efforts the best chance at rescuing and recovering endangered species.Ryder recalls a poster that Frozen Zoo founder Kurt Benirschke had on his wall with a quote from the Librarian of Congress: “We've got to save things for reasons we don't understand.”

The Northern white rhino is on the brink of extinction, and is a key species in The Frozen Zoo.
Credit Photo courtesy of San Diego Zoo Global

At the time, the technology for decoding DNA was in its infancy, and things like genome editing or cloning weren’t even on the horizon. But things were changing quickly.

“We could imagine that there were going to be rapid developments in biological sciences that could take advantage of the access to the unique set of samples that we were banking,” Ryder said. “And, of course, that turned out to be wildly true.”

Today, Ryder and his colleagues at the Institute for Conservation Research are working to transform banked skin samples into stem cells that could, in turn, develop into eggs and sperm. And those, of course, could be used to make real-life baby animals to replenish declining populations – not only boosting numbers, but also increasing genetic diversity to make the population more resilient.

Right now, The Frozen Zoo holds more than 10,000 samples from roughly 1,100 species. On one hand, it’s an impressive number. But it pales in comparison to the million or more species that we could lose this century.

Ryder says that expanding their own collection and building a network of other Frozen Zoos is a top priority.

“That's what I was working on yesterday,” Ryder said, “and what I will work on tomorrow.”