Extinct Tasmanian "tiger" DNA has clues to demise

WASHINGTON Mon Jan 12, 2009 5:53pm EST

This handout photo shows two thylacinus in Washington D.C.'s National Zoo, c. 1906. REUTERS/Smithsonian Institution archives/E.J. Keller/Handout

This handout photo shows two thylacinus in Washington D.C.'s National Zoo, c. 1906.

Credit: Reuters/Smithsonian Institution archives/E.J. Keller/Handout

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WASHINGTON (Reuters) - DNA taken from the hair of two extinct Tasmanian "tigers" suggests the Australian marsupials last seen 70 years ago may have become too inbred to survive as a species, researchers reported on Monday.

The researchers used the method they used to study the DNA from extinct woolly mammoths' hair to get a good comparison of the gene sequences from Tasmanian tigers, formally known as thylacines, and said they hope to study other extinct animals -- and perhaps resurrect one or two of them.

"Our goal is to learn how to prevent endangered species from going extinct," said Webb Miller of Pennsylvania State University, who helped lead the international study.

"What I find amazing is that the two specimens are so similar," said Dr. Anders Gotherstrom of Uppsala University in Sweden, who worked on the study.

"There is very little genetic variation between them."

Species that have little genetic diversity are at risk of extinction -- an example is the modern-day cheetah.

"I am expecting that publication of this paper also will reinvigorate discussions about possibly bringing the extinct Tasmanian tiger back to life," Miller said in a statement.

The thylacine was a striped marsupial that closely resembled a dog. Marsupials are mammals that carry their newborn young in a pouch instead of in the womb, and they are especially common in Australia.

Many resemble mammals found in other areas of the world, something that biologists call convergent evolution.

The thylacine was hunted by European settlers and declared extinct in 1936 when the last zoo specimen died.

The research team pulled and sequenced DNA from the hair of a male thylacine brought to the U.S. National Zoo in Washington in 1902 and a female that died in the London Zoo in 1893.

They got sequences both from the nucleus of the cell, and the mitochondria, where DNA is passed down with few changes from mother to offspring.

Penn State's Stephan Schuster said the work, described in a study in the journal Genome Research, shows it is possible to use hair to resurrect extinct animals -- and perhaps to some day do so in real life.

"The speculation was that the only reason we were able to extract DNA from mammoth hair is that the mammoths had remained frozen in the Arctic permafrost, but our success with the Tasmanian tiger shows that hair can protect DNA for long periods under a variety of environmental conditions," Schuster said.

He calls the method "museomics." "The collections dating back several hundred years and now housed in the world's museums of natural history are the treasure troves of science," Schuster said in a statement.

(Editing by Cynthia Osterman)

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