Oliver Ryder: Frozen Zoo closer to saving endangered species

A “frozen zoo” – inhabited by tissue, skin cells, and DNA from more than 1,000 different animal species – is now a step closer to saving some endangered species from extinction. Scientists took that step in 2010, when they created stem cells – cells that can generate any type of cell in the body – from frozen skin cells of a highly endangered monkey.

Oliver Ryder: We’ve been saving these skin cells for over 30 years, never imagining that it would be possible to turn them into stem cells.

The Frozen Zoo: A cool place for endangered species

Dr. Oliver Ryder is director of genetics at the San Diego Zoo Institute for Conservation Research – home of the Frozen Zoo. He said the Zoo was founded in 1972, and that genetic technology was in its infancy when scientists placed the first skin-cell samples from endangered animals into deep freeze. Now these frozen cells are closer to fulfilling their promise. They could be used to find potential cures for diseases and disabilities for animals that need to be healthy to breed.

Oliver Ryder: The other possible option is that stem cells could be used for reproduction. That is, they could be used for cloning individuals.

Stem cells can generate egg and sperm cells that could produce a new animal, Ryder said. But he said the Frozen Zoo doesn’t plan to use cloning to bring back now-extinct species. Instead, he said, they’ll use cloning to help add diversity to a shrinking gene pool of species that are endangered. Ryder said scientists are still figuring out how the genetic breakthrough at the Frozen Zoo can assist global conservation efforts.

Oliver Ryder: For most endangered species, our ability to intervene on their behalf, and make knowledge-based decisions to assist in their sustainability, is confounded by our lack of information about the biology of the species. Having samples to study can reveal aspects of their biology that were hitherto unknown.

Ryder said that samples are obtained from animals in a number of different ways – when an animal is brought in for a veterinary procedure, quarantined, or after an animal has died. The Frozen Zoo will take a small piece of skin from that animal.

Oliver Ryder: Probably the premier resources are living cells that are frozen in liquid nitrogen and are basically in suspended animation. These are cells called fibroblasts that are taken from the skin or other tissues. They’re propagated in flasks, and then are frozen in several vials.

The samples found at the Frozen Zoo are the largest collection of its kind, Ryder said, with over 8,000 individual samples from around 1,000 different species. One of these species is now extinct, and others are on the spectrum from unthreatened to critically endangered.

Oliver Ryder: We have things as diverse as crocodiles, and ostriches, and elephants, and armadillos, and hippos and giant pandas. For a zoo goer to name a species, we probably have it.

Ryder said that the process to reproduce an animal from the collection of genetic materials would be similar to the creation of Dolly the sheep, the first cloned animal.

November 8, 2010

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