Mapping of the woolly mammoth genome is now complete, bringing scientists one step closer to being able to clone the ancient beasts that died out roughly 4,000 years before the present day. Already, a team of researchers in the United States is working at placing mammoth genes into stem cells taken from modern elephants in an effort to better understand the physical characteristics of the ancient creatures.

De-extinction is a new possibility that has only recently become available to the human race. By taking DNA samples from extinct creatures such as woolly mammoths and placing them into cells belonging to modern relatives, it may be possible to bring back species that have disappeared from the face of the Earth.

Bringing animals such as dodo birds, passenger pigeons and other creatures back to existence is considered, by many people, to be a means to recover losses caused by humans and a way to increase biodiversity. However, critics of the practice claim the idea is immoral since it could result in suffering among the modern animals subjected to breeding with other species.

Analysis of the mammoth genome reveals the species experienced two major population losses that greatly endangered their existence before a third such period resulted in the demise of the last of the animals on an island in the Arctic Ocean. The last off these animals, living off the Russian coast, showed significant signs of inbreeding.

In the movie Jurassic Park, dinosaurs are brought back to existence through the use of DNA trapped in amber. However, genetic material deteriorates significantly over the course of just a few thousand years. Any dinosaur DNA would be too degraded to recover with current technology. Unlike the ancient reptiles, mammoths died out much more recently, and remains of several of the animals have been recovered in near-pristine condition from beneath the ice of Siberia.

Researchers in this study examined genetic codes from a pair of mammoths, including a molar from a 4,000 year-old specimen that lived on Wrangel Island, and the 45,000 year old body of a calf recovered in Siberia. The more recent specimen, which was one of the last surviving mammoths when it walked the Earth, was found to have much less genetic variation than its more ancient cousin.

"The reason for this difference is that the Wrangel individual's genome contained a large number of tracts with no variation at all, which is a pattern that is typical in very small populations where most matings occur between distant relatives," said geneticist Love Dalén of the Swedish Museum of Natural History.

Woolly mammoths first evolved 700,000 years ago, and the study documents the two great losses that hit the species. The first of these took place 280,000 years ago, and the second 12,000 years in the past. A population of just a few hundred of the animals survived on Wrangel Island for 6,000 years after that time.

Mapping of the woolly mammoth genome was detailed in the journal Current Biology.

Photo: Andrew Wilkinson | Flickr