The genome of the woolly mammoth is halfway sequenced and science-fiction fanatics are once again talking about resurrecting extinct species–except this time, the scientists are talking too. Researchers at Pennsylvania State University extracted DNA from the hair of two woolly mammoths found in the permafrost of Siberia; one lived about 20,000 years ago, the other about 60,000 years ago. Reporting in Nature [subscription required], the researchers say they have already sequenced more than three billion base pairs of the mammoth genome, and they say there should be no technical obstacles to sequencing the complete genome. “It’s a technical breakthrough,” says ancient-DNA expert Hendrik N. Poinar [Scientific American].
Access to clumps of preserved mammoth hair was essential to the researchers’ success. The tough keratin that makes up the hair encased the mammoth’s DNA and separated it from any alien fragments, keeping these samples more pure [New Scientist]. Horns and feathers are also made of keratin, broadening the prospects of sequencing other extinct species from museum specimens.
Thus far the mammoth genome exists only in bits and pieces: it has not yet been assembled. The researchers are awaiting completion of the genome of the African savanna elephant, a cousin of the woolly mammoth, which will serve as a road map for how to reconstruct the extinct animal’s genome [Scientific American]. From what they have seen so far, the researchers say that extinct mammoths and living elephants are closer relatives than once thought, with only half the variation that exists between humans and chimps [New Scientist]. Analysis of multiple mammoth genomes may help chart their evolution and reveal the insurmountable factors that led to their disappearance about 10,000 years ago.
The similarities between woolly mammoths and elephants suggests a way to resurrect the extinct species. According to researcher Stephen Schuster, in theory it would be possible to genetically modify an elephant egg cell to closely approximate a mammoth egg cell. The cell could be converted into an embryo and brought to term by an elephant, a project he estimated would cost some $10 million [New York Times]. Schuster believes 400,000 base pair changes would be sufficient to create a mammoth look-alike while several million could create a near replica. New DNA technology currently being developed would be able to modify several thousand genomic sites at once.
A true Jurassic Park scenario, in which dinosaurs are brought back to life, would be more difficult because of a lack of closely related living surrogates.
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Image: flickr / Hawkoffire