An international team of scientists has decoded most of the genome of the woolly mammoth, an important step toward bringing the ice-age giant back to life.
The DNA was extracted from the wiry, reddish-brown hair of mammoths that had been frozen in the Siberian permafrost for more 20,000 years.
It is by the far the most complete genome of an extinct animal ever sequenced.
Pennsylvania State University's Stephan Schuster, lead author of a paper published in Thursday's edition of the British journal Nature, estimates the mammoth genome is now about 80 per cent complete. It is far bigger than he expected, more than 50 per cent larger than the human genome.
“It is not only a big animal, but a big genome,” said Dr. Schuster, with the Center for Comparative Genomics and Bioinformatics at Penn State.
He said the work would not have been possible without the co-operation of a team sequencing the genetic code of the African elephant, a modern relative of the woolly mammoth, which also has a huge genome.
The researchers have begun a more detailed comparison of the two genetic codes. Their goal: to understand the 40,000 genetic changes that made mammoths so different from their modern cousins.
A detailed comparison is an important step toward bringing the ice-age elephants back from the dead, Dr. Schuster said. Using a variety of methods to manipulate DNA, they could reintroduce those changes into the elephant genome.
Ideally, two genetically distinct modern mammoths – one male and female mammoth – would be created.
“That's the minimum required to start a happy family,” Dr. Schuster said.
Scientists could figure out how many mammoth genes would be required to make an elephant look like a mammoth. It may be that only relatively few could make modern creatures that were shaggier and adapted to the cold.
But would they be superficial mammoths, or the real deal?
It is a matter of degree, Dr. Schuster said. He said it would take between $10-million and $20-million to create hybrids with most of the unique bits of mammoth DNA.
As a comparison, it cost more than $1-million to sequence most of the mammoth genome.
There is another, more difficult approach to resurrecting the woolly mammoth, detailed in a news article in Nature titled “Let's Make a Mammoth.”
It would involve creating a modern version of the ancient genome with synthesized DNA, which could be used to build a set of chromosomes, and eventually an embryo that could be carried to term by an African or Indian elephant.
The steps are all exceedingly challenging, including getting a donor egg from an elephant.
McMaster University's Hendrik Poinar collaborated with Dr. Schuster on an initial paper in 2005. They mapped the first 1 per cent of the woolly mammoth gene.
He has been studying mammoth DNA for clues about their biology and why they disappeared. Most were wiped out roughly 10,000 years ago, although a few island populations in Siberia hung on for much longer.
Scientists don't yet have the capability to make a mammoth, Dr. Poinar said, but one day they could.
“I will defer to [filmmaker] Steven Spielberg,” he said. “This is the science of eventuality.”
