April 17, 2001 -- Movies like Jurassic Park, with its fantasy 20th-century dinosaurs, bring to life creatures that have long disappeared from our planet. But we needn’t turn to science fiction to show us lost worlds.
In our own lifetime, it’s estimated that 40,000 species become extinct every year. To help keep a record of this disappearing life, a team of scientists is trying to establish a global DNA bank for endangered animals.
Although banks containing animal genes are scattered throughout the world, this would be the first international effort to collect and compile tissue samples from all known endangered animal species.
Scientists currently must rely on studying fossils and other bits of data to understand extinct animals, like dinosaurs and woolly mammoths. A DNA bank would provide future generations with a more complete and accurate record of now-threatened species, such as black rhinos, giant pandas and tigers.
Oliver Ryder, a geneticist at the Center for Reproduction of Endangered Species, Zoological Society of San Diego, and lead author of the proposal, which was published in last week’s issue of Science, says, “The future will find uses for the information obtainable from DNA banks that we cannot presently imagine.”
While Jurassic Park-like recreations are remote at this point, experiments are under way to freeze the eggs and sperm of endangered species in a process called “cryopreservation.” An embryo may then be implanted into a non-endangered host animal, thus preserving the donor species.
If DNA samples are collected before a species’ population drops to dangerous lows, Ryder and his colleagues additionally believe that preserved cell lines for endangered animals could be replicated. Such nuclear replacement cloning might be able to restore earlier levels of genetic diversity within a species.
Ryder hopes that information from the samples could be available to scientists and conservationists worldwide via a single Web site, perhaps run by a multinational organization.
Project Could Save Species
Many scientists, including Ryder and Rodrigo Medellin, a professor at the Institute of Ecology, National University of Mexico, believe a world DNA bank may also save certain species from imminent extinction.
For example, California researchers already are using genetic information to help save the California condor, a species placed in captivity to prevent its extinction. By analyzing DNA samples, conservationists are able to identify kinship among the birds, which aids in the prevention of inbreeding and the spread of heritable diseases.
Conservationists also are attempting to revive Przewalski wild horse populations throughout the world, particularly in the majestic animal’s native land of Mongolia. In this case, breeders are attempting to preserve an extremely limited gene pool derived from 12 horses that were captured in the wild.
Genetic information is used to monitor commercial products, like canned fish, to make sure they do not contain meat from endangered mammals, such as blue whales and dolphins.
As science and technology advance, information in DNA animal banks might assist medicine and pharmaceutical development by helping to explain how certain genes work.
Medellin adds, “Maybe in the future, when we are wiser and perhaps fewer (in number), we might be able to do something to recover lost species.”
DNA Dangers and Concerns
While collecting animal specimens sounds harmless, the project is somewhat controversial. James Patton, professor of integrative biology at the University of California at Berkeley and director of the university’s Museum of Vertebrate Zoology, says maintaining the security of the bank’s information is a primary concern.
Patton explains that many scientists will be hesitant to release site location data for the collected animal tissue samples because these areas frequently get raided for commercial sales.
“A number of endangered animals are favorites in pet trades and some are used in Asian medicines,” says Patton.
Tampering with nature can also be dangerous, Medellin says. “Opening the box to other uses of DNA, such as genetic ‘improvement’ of [species] or any changes of naturally occurring populations, would probably make the idea of DNA banks even more controversial.” Similar to the arguments surrounding genetically modified food crops, some scientists support DNA experiments on animals, while others are vehemently opposed due to the lack of long-term data on the potential consequences.
Further, we will probably never see black bears and jaguars roaming Earth freely again. As Patton suggests, we will be unable to exactly duplicate lost biodiversity, habitats and complex relationships within ecosystems.
He adds, “Even if we were to able to reconstitute an extinct species, the only place to put it would be in a zoo or a science lab.”