Tue, Aug 31, 2010 - Page 16 News List

Zoo aims to save endangered species from extinction

San Diego Zoo began collecting skin samples from rare animals in 1972 in the hope they might be used to protect these endangered species in the future. A breakthrough in stem-cell technology means that day is getting closer

By Paul Harris  /  THE GUARDIAN , LONDON

It has also raised another prospect among some observers: that of a Jurassic Park scenario. If viable cell samples could be harvested from the remains of extinct animal species, such as stuffed Tasmanian tigers in museums or the woolly mammoth corpses dug up from the Siberian tundra, then perhaps scientists would one day be able to reverse extinction. It is not a prospect that many scientists involved want to encourage. But ever since news of Loring’s work with the drill monkey cells was revealed, the Jurassic Park headlines have been coming thick and fast.

Loring’s lab at Scripps holds samples from the northern white rhino and the drill monkey, but the real Frozen Zoo, just a few kilometers away, is on a much larger scale. Housed in a building inside San Diego Zoo, its freezers contain samples from 8,400 animals, representing more than 800 species. They include Gobi bears, endangered cattle breeds such as gaurs and bantengs, mountain gorillas, pandas, a California gray whale and condors. The entire gigantic menagerie is housed in four deep-freeze tanks, representing a staggeringly important slice of some of the world’s most rare wildlife.

Oliver Ryder, the geneticist who heads the Frozen Zoo program, welcomes the news of Loring’s work, which itself built on a breakthrough in 2007 by Japanese scientist Shinya Yamanaka. For Ryder it is confirmation that the zoo’s founding as a sort of “bet” on the science of the future now has great prospects of paying off. “We wondered if one day pigs would fly. Well, now pigs are flying. I am very excited by the results,” Ryder says.

But Ryder does not appreciate some of the wilder headlines that have sprung from the potential implications of the research. The words “Jurassic Park” get short shrift from the plainspoken scientist. He has little time for those who advocate bringing back long-dead species or those fringe figures who dream one day of recreating a dinosaur just like in Steven Spielberg’s movie. Apart from the fact that the science of extracting viable DNA for such animals is virtually impossible, he believes it distracts from the Frozen Zoo’s primary aim: to stop species becoming extinct in the first place. “What would be the benefit of bringing back something that has been extinct for some 10,000 years? It is intriguing and evocative but it plays to human hubris. What’s the motivation? Is this for personal benefit or society saying: ‘We have arcane powers and the world is our oyster,’” he says.

When it comes to species still on the brink, with perhaps just a few individuals left, however, Ryder is insistent that humanity has a duty to save them and that the Frozen Zoo can play a crucial role. Especially close to Ryder’s heart is one of the species that Loring is working on: the northern white rhino. There are just eight of the animals left alive on Earth and not all of them are viable breeders. But, if Loring’s work succeeds in creating northern white rhino induced pluripotent stem cells and then turning them into sperm and eggs, that gene pool can be deepened again.

It is a race against time. Unlike with the drill monkey, Loring’s efforts with rhino cells have not yet worked. But at least Loring thinks she knows why. The drill monkey samples were coaxed into becoming induced pluripotent stem cells using viruses loaded with carefully selected human genes that can trigger that reaction. Loring suspects it worked with drill monkeys because — as fellow primates — they are genetically close enough to humans for the introduced human genes to work properly. Rhinos, she thinks, may be too distantly related. However, she plans to try again, this time perhaps using genes from a closer animal relative to the rhino, the horse.

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