SAN DIEGO — Conservation scientists have achieved a major milestone in saving wildlife species.
Marlys Houck is the curator of San Diego Zoo Wildlife Alliance’s Frozen Zoo. She leads a team who works year-round to collect, grow and preserve cell lines. According to SDZWA, no other biobank in the world has a comparable number of living cell lines, with the potential to reverse losses of genetic diversity and contribute to population sustainability for endangered and threatened wildlife species.
“Birds, mammals, reptiles, amphibians and a couple of fish. And it’s the largest, most diverse collection of its kind in the world,” Houck said.
The team collects skin or other tissue from a variety of mammals, birds, reptiles, amphibians and fish, either after an animal has died or during a routine veterinary exam. From those tissues, living fibroblast cells are grown, and then stored in liquid nitrogen freezers at a temperature of -320 degrees Fahrenheit.
The collection includes living cells that came from the San Diego Zoo Safari Park’s iconic northern white rhinoceros named Nola, who died in 2015. Currently, there are only two female northern white rhinos left in the world.
“We were able to freeze [Nola’s] cells both before she died when the vets took a sample and also after she died,” Houck said. “People ask ‘what’s the most important box,’ and every box is important. Just the variety and diversity are what make this collection so unique.”
The Frozen Zoo was established nearly 50 years ago and recently hit a huge milestone for conservation. With the addition of a wood turtle and a Javan rhinoceros hornbill cells, the Frozen Zoo has banked more than 11,000 individual cell lines, representing 1,300 subspecies, some critically endangered.
Manuela Figueroa is a senior wildlife care specialist who works at the Nikita Kahn Rhino Rescue Center. She helps take care of Edward, the first southern white rhino born by artificial insemination in North America. His birth is regarded as a major conservation success story. Figueroa said now the goal is to create a northern white rhino embryo, carried by a southern white rhino surrogate.
“The southern white rhinos are here to help bring back their cousins, so to speak, to be surrogate mothers eventually to a northern white rhino calf,” she said. “And the way that we do that is through the Frozen Zoo.”
Figueroa said the work happening offers hope for species conservation.
“Crazy to think that maybe we can change or reverse the effects that humans have had,” she said.
There are 12 northern white rhino cell lines in the Frozen Zoo. Houck said there are decades of dedication in every tank.
“What will happen with cells we froze fifty years from now? What could they be used for? We hope bringing species back from the brink of extinction,” Houck said.
Houck said many conservation projects need living, dividing cells to be successful, not just DNA. The San Diego Zoo Wildlife Alliance’s Frozen Zoo team receives and shares samples and data with hundreds of scientific collaborators worldwide to aid in conservation efforts. In addition, they offer their expertise to other organizations on how to acquire samples from deceased wildlife, establishing cell lines and studying chromosomes.