Jan. 12, 2009 -- Until recently, little was known about the mysterious Tasmanian tiger, but new DNA sequences of the dog-like marsupial shed light on the striped creature's surprising family tree and its extinction 73 years ago. Researchers now believe the Tasmanian tiger, also called the thylacine, went extinct in 1936 after the death of the last known surviving individual at a Tasmanian zoo, and four decades after genetic diversity within the species dropped to a critically dangerous low. It's thought that the thylacine's path to extinction, however, began much earlier. "Thylacines were eliminated from mainland Australia around 3,000 years ago, perhaps because of competition from dingos, so the extinction process started that early," said Webb Miller, who led the new study, which is published online in Genome Research. Related Content: Get the Latest in Science and Tech News From Discovery Jennifer Viegas' Blog: Born Animal HowStuffWorks.com: Extinction Theories "Between 1803, when Tasmania was settled by Europeans, and the 1930s, pressure was put on thylacines, including bounties, because of supposed predation of sheep," added Miller, a Penn State biology professor. "Apparently a disease epidemic swept through the thylacine population around 1900 to 1910, which didn't do them any good, but it is difficult to say how much, if any, that affected their extinction." Miller and his team used state-of-the-art DNA sequencing technology to analyze the hair of two preserved specimens: a female thylacine that died at the London Zoo in 1893, and a male brought to the National Zoo in 1902 that died three years later. Although the two thylacines were continents apart, their mitochondrial DNA -- a portion of the genome passed on via the maternal line -- was nearly identical, illustrating the species' ultra-low genetic diversity around the turn of the 20th century. The DNA analysis also determined that, despite the fact that the thylacine resembled a cross between a dog and a tiger, it was a marsupial closely related to striped insect-eaters called numbats, and more distantly to kangaroos and koalas. Get More NewsMouse Cloned From Long-Frozen CellResearchers create a mouse from a long-frozen cell. Will the mammoth be next?'Bubble' Could Protect AstronautsScientists say a "bubble" around a Mars-bound spaceship could protect astronauts.Big Reduction of Snowmobiles in Yellowstone ProposedA new plan would cut snowmobile use by 40 percent in Yellowstone.Microbes: Fuel of the Future?A reddish South American microbe is literally breathing fuel, say scientists.DNA Links Remains to Steve FossetDNA tests on two bones found in California confirm they are those of Steve Fossett.Women Carry More Bacteria Than MenSome bacteria prefer women, suggests a new study. But why?Ancient 'Water Monster' Facing ExtinctionA foot-long salamander that was a key part of Aztec legend is threatened by extinction.Grand Canyon's Youth ConfirmedThe Grand Canyon is millions of years younger than previously thought, argue geologists.My Take: E-Voting Not User FriendlyOpinion: Electronic voting machines don't always capture the intent of voters.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.At 40, Brain and Body SlowThe part of the brain in charge of motion starts a gradual slide in middle age.Spiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates. |
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