A global animal population has declined by 69% since 1970, underscoring a dire biodiversity crisis that has experts turning to an innovative solution to help avoid species extinction. Similar to how frozen eggs offer humans the option of delaying reproduction, the technology of cryogenically freezing animal genetic samples could also be the key to halting the decline of various species.

Researchers highlight the huge potential of cryogenic libraries, which can store various genetic materials of animals at ultra-low temperatures, in protecting dwindling animal populations around the world. The study was supported by several global conservation agencies, and the researchers recommend that future sampling of species should be prioritized and a global cryobank database established to facilitate collaborative conservation efforts and potentially reintroduce threatened species into their natural habitats.

A recent paper published in the journal Zoo Biology highlights the far-reaching promise of cryobanks or live cell banks in addressing global conservation challenges.

These living cell banks preserve animals’ genetic material, such as DNA, embryos, semen and living tissues, at ultra-low temperatures. These cells can be cultured for a variety of purposes, including genetic analysis, assisted reproductive technology, ensuring the genetic diversity of animal populations, and even potentially reintroducing species into their natural habitats.

In this study, researchers analyzed the contents of the San Diego Wildlife Alliance (SDZWA) Frozen Zoo, the largest and most diverse repository of living genetic samples in the world, to develop a framework for prioritizing species for future sampling. The researchers also used aggregated data from the Species360 Zoological Information Management System (ZIMS), the world's largest database of species knowledge, to identify opportunities for future genetic sample collection.

Research results show that the SDZWA Frozen Zoo currently stores 965 different species, including 5% of amphibians, birds, mammals and reptiles, and further collection of samples from zoos and aquariums can significantly increase this proportion to 16.6%, resulting in an additional 707 endangered species.

Additionally, 50% of genetic samples from species currently listed as extinct in the wild are already preserved in the SDZWA cryozoological park, but sampling from the zoo could increase this number to 91%, potentially providing a vital lifeline to these endangered species.

Lead author of the study, Dr Andrew Mooney from Dublin Zoo and the School of Natural Sciences at Trinity College Dublin, stressed the significance of the study, saying: "This study not only Highlights the efforts of Dublin Zoo and the School of Natural Sciences at Trinity College Dublin in protecting endangered species, and also provides valuable experience for Dublin Zoo and the School of Natural Sciences at Trinity College Dublin. "

"This study not only highlights the incredible work done to date by the San Diego Zoo Wildlife Alliance, but also exemplifies the collective potential of the global zoo and aquarium community to further advance global cryobanking programs and conservation priorities. As wildlife populations continue to decline around the world, there has never been a more critical time to collect and preserve genetic samples from endangered species. Frozen samples offer unparalleled conservation opportunities, however, we must come together and collect samples now before it is too late." "

Yvonne Buckley, Professor of Zoology in the Department of Natural Sciences at Trinity College, said:

"We are in the midst of a biodiversity extinction crisis, with more than a million species likely to be threatened with extinction in the coming decades. While our priority is to prevent species from declining in the wild, cryopreservation provides a means to protect critical genetic diversity and reintroduce it into populations to increase their fitness and resilience. "

"This study highlights the huge potential of cryopreservation in protecting endangered species, and the role of zoos and aquariums in conservation," said study co-author Johanna Staerk of the Species 360 Conservation Science Alliance. Given the difficulty of obtaining genetic samples from wild species, zoos and aquariums provide ideal resources to collect genetic samples to ensure the future survival of species."

Oliver Ryder, Kleberg Endowed Director of Conservation Genetics at the San Diego Zoo Wildlife Alliance (Oliver A. Ryder) said:

“The cryopreservation of viable cells by cryozoologists for more than four decades has provided a large and influential resource for genomics-based biodiversity discovery and demonstrated the possibility of cell-based genetic rescue.” Countries around the world urgently need to scale up their efforts to establish distributed biobank networks to make cell-based genetic resources available in an equitable manner and provide conservation options for future generations. "

Marlys Houck, curator of the San Diego Zoo Wildlife Alliance Frozen Zoo and co-author of the study, said:

" Dr. Kurt Beniske created the Frozen Zoo in 1975, and hundreds of specimens are added to it every year. Thanks to his foresight, we have cell lines of species and individuals stored decades ago, some of which have not yet been propagated. Their genetic diversity is not represented in current populations, but could allow for future genetic rescue through samples from frozen zoos. "

In addition to suggesting a framework for which species need to be prioritized for genetic sampling, the study's authors encourage the establishment of a global database of cryobanks to facilitate collaboration in the conservation of genetic diversity.

The study was a result of the International Union for Conservation of Nature (IUCN) Conservation Planning Specialist Group (CPSG) 2 The outcome of a workshop held during the 2016 conference, organized by the Species 360 Conservation Science Alliance in partnership with Oliver Ryder of Frozen Zoo TAGP. H20

The role of cryogenic gene banking in saving species from extinction

The powerful role of cryopreservation in conservation is demonstrated in efforts to save the now functionally extinct northern white rhinoceros. With only two female white rhinos left alive, scientists are using samples from frozen zoos to save the subspecies from disappearing forever through assisted breeding techniques.

While the example of the northern white rhino represents a last-ditch attempt to save the subspecies, the study authors stress the importance of being proactive in prioritizing species and building a global cryodatabase to ensure conservation action can be taken faster.

Cryopreservation may be the only lifeline to save endangered species, such as northern white rhinos and killer whales, for which living cell cultures are available. Unfortunately, these possibilities will never be realized for the recently extinct Yangtze finless porpoise and Christmas Island lizard, as there are no live biological samples for them.

However, there are still sampling opportunities for most species. Considering that 71% of species listed as "least concern" on the IUCN Red List of Threatened Species are at risk of extinction due to the effects of climate change, storing genetic samples now could help protect these species in the future.