Scientists aim to clone threatened species
Researchers have collected DNA samples from dead animals to bolster future zoo populations
RIO DE JANEIRO — Brazilian researchers are turning to cloning to help fight the perilous decline of several animal species.
The scientists at Brazil’s Embrapa agriculture research agency said this week they have spent two years building a gene library with hundreds of samples from eight native species, including the collared anteater, the bush dog, the black lion tamarin, the coati, and deer and bison varieties, as well as the leopard and the maned wolf.
While still in its early stages, with the birth of a clone likely years away, the project represents Brazilian scientists’ first foray into the cloning of wild animals, said team leader Carlos Frederico Martins.
Scientists in other parts of the world have been cloning threatened species for more than a decade, though with a low rate of success, and sometimes with the criticism of conservationists who say more should instead be done to save endangered animals in the wild by protecting their natural habitats.
Martins said any clones that eventually emerge from the Brazilian project would go to zoos, not into the wild.
“The idea is not to use cloning as a primary conservation tool,” Martins said in a phone interview from a farm outside the national capital, Brasilia. He stressed that clones don’t resolve one of the main problems facing species with dwindling populations, which is maintaining a sufficiently varied gene pool.
“Let’s be clear that cloning can’t be a substitute for protecting endangered animals’ habitats,” Martins said. “It’s a
Let’s be clear that cloning can’t be a substitute for protecting endangered animals’ habitats.
CARLOS FREDERICO MARTINS TEAM LEADER OF SCIENTISTS EXPLORING CLONING IN BRAZIL
way to aid zoos beef up their collections, particularly for animals that don’t easily breed in captivity.”
The Embrapa project’s top candidate for initial cloning is the maned wolf, a towering canine one metre tall at the shoulder, with long legs and a thick red pelt. With an estimated total population of 23,600, the vast majority of them in Brazil, the maned wolf is classified as “near threatened” on the ICNU Red List of Threatened Species, which is widely considered the definitive source on threatened species.
The wolf could prove easier to clone than the other species in the library because it’s a good candidate for interspecies cloning. A skin cell from the wolf would be inserted into the egg of a common dog from which the nucleus had been removed, and then implanted into the uterus of a dog, which would serve as the cloned wolf pup’s surrogate mother.
Nearly all the samples in the Embrapa team’s gene library were culled from the bodies of dead animals, generally roadkill brought in from the Cerrado, the vast tropical Savannah that surrounds Brasilia. Sperm, eggs and skin cells are collected from the cadavers and stored in liquid nitrogen at - 196 C, Martins said.
If officials approve a pending partnership with the city’s zoo, staff there will be trained to take samples from live animals from its collection, Martins said.
“The idea is to be able to expand the gene library to include more samples and also more species under pressure,” said Martins.
The cloning of animals became a reality in 1996 with the birth of the Dolly the sheep. Dolly developed a virusinduced lung disease and was euthanized at age six — about half the life expectancy of her breed — but she gave birth to four lambs.
Cloning remains a difficult enterprise with a success rate of about five to seven per cent. The first reported cross- species clone, a wild ox called a gaur which was born to a cow in 2001, died of dysentery two days later. Martins said new techniques might boost the Brazilian team’s success rate to about 12 per cent.
Martha Gomez, a senior scientist at the Audubon Center for Research of Endangered Species in New Orleans, applauded the Brazilian effort but cautioned that any actual clones could be a long time off.
“I like the idea because I feel that it’s important, but it’s a really big challenge,” said Gomez, who has used house cats and interspecies cloning to produce African wildcats.
“When you talk about cloning, you not only need the people, you need the infrastructure, the resources and the animals,” she said. “The cloning between species can be very different. It’s not going to be the same to clone a jaguar or a wolf, and cloning a tamarin is going to be even harder,” Gomez said.
“I think they can do it, but it’s a very long- term project, that’s for sure.”