Posts Tagged ‘genetic hybrid’

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PLEISTOCENE PARK…

10/17/2011

woolly mammoths and the restoration of an Ice-Age ecosystem…

by STEFAN LOVGREN 

During the last ice age northeastern Siberia remained a grassy refuge for scores of animals, including bison and woolly mammoths. Then, about 10,000 years ago, this vast ecosystem disappeared as the Ice Age ended.

Now, though, the Ice Age landscape is on its way back, with a little help from the Russian scientists who have established “Pleistocene Park.”

The scientists hope to uncover what killed off the woolly mammoth and other Ice Age animals. To do so, they’re restoring the prehistoric ecosystem once found in what is now the remote Sakha region of eastern Russia.

The land is slowly being turned into willow savanna, as it was 10,000 years ago. Dozens of wild horses are already grazing in the refuge, and there are plans to import bison and musk oxen.

Most spectacularly, the wildlife park may one day become home to a genetic hybrid of the extinct woolly mammoth and the modern-day elephant. But the park probably will not see its most majestic potential inhabitant for several decades, if ever.

Japanese scientists, working with Russians, have for years been searching for mammoth carcasses to use for reviving woolly mammoths, which would then be introduced into Pleistocene Park.

The plan: to extract sperm DNA from frozen mammoth remains and inject it into a female elephant’s eggs to produce a hybrid offspring. By repeating the procedure over generations, scientists would eventually create an animal that is mostly mammoth.

One problem, however, has been finding mammoth DNA that is sufficiently well preserved in ice to still be viable. The DNA in mammoth fossils that have been found has been unusable, damaged by time and climate changes.

Also, many mammoth experts scoff at the idea, calling it scientifically impossible and even morally irresponsible.

“DNA preserved in ancient tissues is fragmented into thousands of tiny pieces nowhere near sufficiently preserved to drive the development of a baby mammoth,” said Adrian Lister, a paleontologist at University College London in England.

Great Mystery

Sergey Zimov, who is not involved in the mammoth-recreation effort, initiated the project to restore the Pleistocene ecosystem in 1989. He hopes to test the theory that hunting, not climate change, wiped out the animals that once thrived in northern Siberia.

“I want to show how many animals can exist if nobody hinders them to live,” said Zimov, who directs the Northeast Science Station in Cherskiy, about 93 miles (150 kilometers) south of the Arctic Sea in the Russian republic of Sakha (also known as Yakutiya).

In the area of Sakha where the park is located, temperatures fluctuate between highs of about 85 degrees Fahrenheit (30 degrees Celsius) in the summer and lows of -58 degrees Fahrenheit (-50 degrees Celsius) in the winter.

During the driest periods of the Pleistocene, which lasted from about 1.8 million to 10,000 years ago, the vegetation was mainly low grass.

During warmer periods the land turned into meadows and steppes, ideal grazing grounds for woolly mammoths, rhinoceroses, bison, horses, elk, and yaks. Among the predators were cave lions and wolves.

When this vast ecosystem disappeared 10,000 years ago, the land turned into mossy tundra. The only plant eaters to survive were reindeer that grazed on lichens and moose that fed on willows.

The cause of the extinctions of large animals such as woolly mammoths has been a topic of great debate. Many scientists argue that the sudden shift to a warmer and moister climate proved catastrophic to the steppe vegetation and the animals that thrived on it.

“I’m completely on the side of natural, environmental causes of extinction,” said Andrei Sher, a well-known paleontologist at Moscow’s A.N. Severtsov Institute of Ecology and Evolution.

Skilled Hunters?

Zimov, however, believes that humans, using increasingly efficient hunting practices, killed off the woolly mammoths and the other large animals.

But could a small population of hunters kill millions of animals?

“Imagine a picture in which someone from the neighboring tribe teaches you to make new … weapons” such as spears, Zimov said.

“Now you kill the first animal. Will you carefully prepare and consume all the meat, surrounded as you are by clouds of mosquitoes? Or will you just cut out the tongue, knowing that there are millions more [animals]?

“Over time, people probably understood that they should take care of the animals, but by then it was too late,” he added.

By reintroducing the Pleistocene animals, Zimov says scientists may be able to determine what role the animals played in maintaining their own habitat. Researchers may also better understand the forces that vanquished the Ice Age ecosystem.

While much of the Siberian tundra is now covered with moss, the 160 square kilometers (62 square miles) designated for the park is an even split of meadow, larch forest, and willow shrubland.

“All plants that were there in the Pleistocene epoch are preserved there today,” Zimov said.

The park will eventually be cordoned off, though it will remain open to adventurous tourists who can get to such a remote location, which is accessible only by helicopter.

So far, only 20 square kilometers (about 8 square miles) have been fenced off. Within the park hardy Yakutian horses, the closest descendants of the Pleistocene horse, roam alongside reindeer and moose. Plans to import of Canadian bison, however, are on hold due to fears of bovine spongiform encephalopathy (BSE), or mad cow disease.

Zimov says he hopes to increase the density of plant eaters sufficiently to influence the vegetation and soil in the park and stabilize its grasslands. Once herbivore populations have been established, the plan is to acclimatize Siberian tigers, predators whose modern survival is threatened by poaching.

(NATIONAL GEOGRAPHIC NEWS  5.17.05)

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