Extinct mammoth DNA decoded
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Sunday, 18 December 2005, 18:03 GMT
Extinct mammoth DNA decoded
By Helen Briggs
BBC News science reporter
Scientists have pieced together part of the genetic recipe of the extinct woolly mammoth.
The 5,000 DNA letters spell out the genetic code of its mitochondria, the structures in the cell that generate energy.
The research, published in the online edition of Nature, gives an insight into the elephant family tree.
It shows that the mammoth was most closely related to the Asian rather than the African elephant.
The three groups split from a common ancestor about six million years ago, with Asian elephants and mammoths diverging about half a million years later.
"We have finally resolved the phylogeny of the mammoth which has been controversial for the last 10 years," lead author Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told the BBC News website.
Ice age wanderer
Mammoths lived in Africa, Europe, Asia and North America between about 1.6 million years ago and 10,000 years ago during the Pleistocene epoch.
"It is the longest stretch of DNA [decoded to date] from any Pleistocene species,"
Michael Hofreiter
The woolly mammoth, Mammuthus primigenius, with its covering of shaggy hair, was adapted to the extremes of the ice ages.
The DNA of several extinct ice age mammals, preserved in permafrost, has been analysed before, but not in such detail.
"It is the longest stretch of DNA [decoded to date] from any Pleistocene species," said Professor Hofreiter.
Maternal line
The team of researchers - from Germany, the UK, and the US - extracted and analysed mammoth DNA using a new technique that works on even the tiny quantities of fossilised bone - in this case 200 milligrams.
Some 46 chunks of DNA sequence were matched up and arranged in order, giving a complete record of the mammoth's mitochondrial DNA - the circular scrap of genetic material found outside the cell's nucleus.
It is passed down the maternal line with small but regular changes, giving scientists a window into the past.
Although the bulk of an animal's genetic information is found in the nucleus, mitochondrial DNA is particularly useful for studying the evolutionary relationships between different species.
The complete mitochondrial DNA of an extinct animal has been sequenced before but only for the flightless bird, the moa, which died out about 500 years ago.
Dan Bradley, an expert in ancient DNA at Trinity College, Dublin, Ireland, said the research was "a bit of a landmark".
"Most ancient mitochondrial DNA projects use just small parts of the mitochondria," he said.
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Are they going to clone the extinct mammoth?? They should clone dinosaur instead!!
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Decoding of Mammoth Genome Might Lead to Resurrection
By Robert Roy Britt
LiveScience Managing Editor
posted: 19 December 2005
12:40 pm ET
Scientists have mapped part of the genome of the woolly mammoth, a huge mammal that's been extinct for about 10,000 years.
The breakthrough could lead to recreating the creatures.
A team led by Hendrik Poinar at McMaster University unlocked secrets of the animal's nuclear DNA by working with a well-preserved 27,000-year-old specimen from Siberia. Colleagues at Penn State sequenced 1 percent of the genome in a few hours and say they expect to finish the whole genome in about a year if funding is provided.
"We were stunned," Poinar said today. “Once you successfully sequence a genome, there are a million interesting questions one can begin to address."
The researcher can now begin to determine what separates mammoths from their closest living relatives, the Indian elephant.
Make mammoths?
“More importantly our discovery means that recreating extinct hybrid animals is theoretically possible," Poinar said.
The scientists are already pondering the ethics involved.
"McMaster is already planning the first conference devoted to the ethics of bringing extinct organisms back to life," said Mamdouh Shoukri, vice-president research and international affairs. "We have an obligation as scientists to explore and maintain the responsible use of research."
Researchers admit, however, that creating an extinct beast from scratch is not something they know how to do yet.
“While we can now retrieve the entire genome of the woolly mammoth, that does not mean we can put together the genome into organized chromosomes in a nuclear membrane with all the functional apparatus needed for life," said Ross MacPhee, a researcher at the American Museum of Natural History who worked on the project. "We can't even do that with modern DNA."
The study will be detailed later this week in the journal Science.
The decoding was announced earlier than planned because a second study was reported in the media Sunday. In the other work, researchers sequenced mitochondrial DNA from a mammoth, but that reveals only the maternal side of evolution. Poinar said his project decodes both sides by looking at the nuclear DNA, where the majority of life's software resides.
Hunted by humans
Mammoths roamed Siberia and America during the Pleistocene era, which ended 10,000 years ago as the last Ice Age retreated. Studies have shown that their demise was due largely to hunting by humans, not from climate change as one theory held.
The breakthrough has been anticipated recently as other work has made similar progress. Scientists in June said they had unraveled snippets of the genetic code of an extinct bear species.
Other researchers have expressed a desire to revive the mammoth by injecting frozen sperm DNA—if they can find some—into elephants. Over several generations, they'd create a creature that's 88 percent mammoth.
The DNA revealed by Poinar's groups is "very similar to the African elephant genome," the group writes in their journal paper.
In August, an American research team proposed restoring elephants, cheetahs and other African animals to the American plains. And a Russian team has created a Pleistocene Park to investigate mysteries of the mammoth.
http://livescience.com/animalworld/051219_mammoth_dna.html