December 22, at am. Thousands of years ago, an elephant-like creature called the woolly mammoth roamed Earth. Modern elephants and woolly mammoths share a common ancestor that lived about 6 million years ago. Now, researchers are using modern techniques to piece together ancient elephant history. The woolly mammoth appears to be more closely related to the Asian elephant than to the African elephant. From looking at fossilized bones and other features, scientists had proposed that woolly mammoths are more closely related to Asian elephants than to African elephants.
Tiny pieces of evidence from the genetic material DNA, on the other hand, hinted at the opposite conclusion. Only recently has technology become available to recreate a genome based on old, damaged DNA. An African elephant. The African elephant has larger ears and a larger forehead than the Asian elephant does.
Both males and females have tusks. The animals appear in the fossil record about 28 million years ago, and survived in North America until about 10, years ago.
The cause of their demise is controversial. The oldest previous mitochondrial DNA genome sequenced belonged to a 33,year-old woolly mammoth. Moas, giant flightless birds from New Zealand that are thought to have died out by about AD, are the only other extinct species to have their complete mitochondrial genome decoded by scientists. Eske Willerslev of the University of Copenhagen and his colleagues recently sequenced mitochondrial DNA from beneath Greenland's ice sheet dated at between , and , years old see ' DNA reveals a green Greenland '.
Some researchers have claimed finding million-year-old bacterial DNA. But such claims do not convince Willerslev. Visit our newsblog to read and post comments about this story. Rohland, N. PLoS Biol. Article Google Scholar. Download references. You can also search for this author in PubMed Google Scholar. Reprints and Permissions. Buckley, L. Mastodon DNA sequenced. Nature Download citation. An elephant in Samburu National Reserve in Kenya stands tall among her herd.
In this week's Science another team published the results of its own woolly mammoth genetic study, which decoded the longest-ever sequence of the animal's genome. The team, led by biologist Ross D. MacPhee of the American Museum of Natural History, compiled some 13 million DNA base pairs—a small but significant part of the animal's complete genome.
The human genome was decoded only six years ago, and no complete genomes have yet been sequenced for extinct animals. The results raise the specter of cloning or recreating the extinct animals from frozen bits of their ancient DNA, perhaps to populate some type of real-life "Jurassic Park. We can't even do that with modern DNA," he said. Though the mammoth genome might not bring the extinct animals back to life, it could help scientists learn why they vanished.
Comparing ancient DNA with the genomes of living animals might help scientists learn what factors cause new species to arise while others perish. Retrieving mammoth bone, even well-preserved bone that can yield DNA, is not as difficult as might be supposed, scientists say. The beasts roamed Siberia until about 10, years ago, when scientists believe they became extinct due to warming weather, human hunters, disease, or some combination of these factors. There are believed to be millions of mammoths buried in Siberia's permafrost.
Only about a hundred specimens have been uncovered in the sparsely populated countryside—but some of them have been remarkably well preserved.
There will be some things to resolve and maybe some interesting surprises as well. All rights reserved. Share Tweet Email. Read This Next Wild parakeets have taken a liking to London.
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