The Frozen Zoo: A cool place for endangered species

A breakthrough at San Diego’s Frozen Zoo could mean new life for endangered species.

Let’s get this out of the way: A frozen zoo does not involve animals trapped in blocks of ice. It’s more like a seedbank for animals – a way of storing genetic diversity for future generations, preserved within  samples of frozen tissue, skin cells, and DNA frozen in liquid nitrogen.

Pieces of animals in test tubes, in other words.

The San Diego Institute for Conservation Research has one of the largest frozen zoos in the world. It’s home to over 8,000 individual samples from over 1,000 species, some of them endangered. The zoo was founded in 1972, for the purpose of collecting material to study animals’ genetics. But now, geneticists working with the Frozen Zoo have figured out how to turn skin cells into stem cells – which could actively help save endangered species.

“We’ve been saving skin cells for over 30 years, never imagining it would be able to treat cells to unleash metabolic activity that would turn them into stem cells,” Oliver Ryder told me. He’s the director of the Frozen Zoo. He said that scientists have converted skin cells into stem cells in mice and humans, and now the same has been done for Africa’s most endangered monkey. That’s a breakthrough for the Frozen Zoo.

Stem cells can generate any type of cell in the body, and Ryder said they hold the same promise for animals as they do for humans. They could mean new treatments for debilitating diseases that keep animals from breeding. Ryder explained that when you have a critically endangered species – for example, the California Condor had only 22 individuals at its lowest point – it’s extremely important that each animal continue to reproduce.

“So if we had an individual whose genetic contributions for a small population were highly desired, but it had some infirmity like arthritis –  if we could assist in reducing that problem then the animal could breed,” Ryder said.

The other possibility, he said, is that the stem cells could be used to clone animals. That means creating an egg, and a sperm cell to make a viable embryo. It’s been done before (remember Dolly?) but never before with endangered animals. However, Ryder doesn’t intend to clone a species back to health.

“To use this for endangered species, to make copies of one single animal, wouldn’t serve a conservation purpose,” Ryder said.  “But if the animals themselves had been saved that had unique genetic contributions that would represent a long lost, or irreplaceable individual in the breeding program to preserve the genetic diversity of the species, then by producing that individual by cloning, that could assist in the maintenance of a self-sustaining population to prevent extinction of a critically endangered species.”

The possibilities of cloning animals out of test tubes brings to mind visions of Jurassic Park with (fingers crossed) less dangerous animals, but Ryder quickly dissuades those ideas. “I think bringing back extinct animals – especially ones that have been extinct for a long time – isn’t an appropriate use of the current resources in a time of vanishing biodiversity,” he said.

Okay, so no dodo bird petting zoo. The Frozen Zoo sees the stem cells as a potential tool in a larger conservation effort. But it could someday end up making the difference in whether a species goes extinct or not.

Lindsay Patterson