for National Geographic News
The thick coats of shaggy hair that kept woolly mammoths warm on the icy tundra have yielded enough intact DNA to sequence their genomes, a new study reports.
In addition to helping scientists figure out why mammoths went extinct, the feat could pave the way for better and faster genetic studies of other ancient animals.
Scientists obtained ten complete mitochondrial genomes using tufts of hair from mammoths that died between 50,000 and 12,000 years ago in what is now northern Siberia, a region of Russia.
Mitochondrial DNA is passed from mother to offspring, so it helps scientists sort out lineages, determine genetic diversity, and address other population mysteries (get a genetics overview).
Before this study, only seven mitochondrial genomes from extinct animals had been created: four from ancient birds, two from mammoths, and one from the mammoth's elephant-like relative the mastodon.
The DNA used to create such genomes usually comes from bone or muscle, which degrade quickly and are easily contaminated with genetic material from other sources such as bacteria.
The process of finding enough uncontaminated DNA to piece together a complete genome from bone or muscle can take several years.
"It is not very efficient," said Stephan Schuster, a study co-author and associate professor of biochemistry and molecular biology at Pennsylvania State University.
"On the other hand, the hair shaft is like a biological plastic, and the bacteria cannot penetrate it."
Schuster and a team of international colleagues report their findings in tomorrow's issue of the journal Science.
Schuster's team devised a method to retrieve unharmed DNA from below the mammoth's hair shaft.
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