Wooly Mammoth DNA Sequenced from Hair
MELISSA BLOCK, host:
Scientists are reporting they have a new way to get genetic information from animals that have long been extinct. They extract DNA from an animal's hair. Using the technique, researchers were able to sequence the DNA of a woolly mammoth that died nearly 50,000 years ago.
Here's NPR's Joe Palca.
JOE PALCA: DNA is a pretty sturdy molecule. Store it in a cool, dry place and at least fragments of it can last for thousands, even tens of thousands of years. The biggest problem in studying such ancient DNA is making sure you're actually studying the DNA of the animal you're interested in and not more modern DNA from bacteria that took up residence in your ancient specimen.
Enter molecular biologist Thomas Gilbert, he'd done some work on trying to extract DNA from hair, and he realized it's easy to clean the bacteria off of hair.
Dr. THOMAS GILBERT (Molecular Biologist, Center for Ancient Genetics, University of Copenhagen): Put a bit of bleach on and you wipe off all the bacteria just like you're cleaning a kitchen surface at home.
PALCA: So Gilbert and his colleagues at the Center for Ancient Genomics at the University of Copenhagen and collaborators at Penn State in this country obtained hair samples from 10 woolly mammoth carcasses that have been collected from the Siberian permafrost, and all of these animals had been dead for 10,000 years or more.
As they report in the journal Science, they were able to get the complete sequence of all 10 animals' mitochondrial DNA. Mitochondria are tiny structures inside cells and it turns out they have their own DNA. Gilbert says two scientific teams have previously sequenced the mitochondrial DNA from woolly mammoths.
Dr. GILBERT: Their studies took quite a long time to achieve. I mean, I think a couple of years, at least in one of them. And using our method, we can do it, you know, easily in less than a week.
PALCA: Gilbert says until now, scientists have mainly used an animal's bones to get at ancient DNA.
Dr. GILBERT: And one of the nice things of course is that in the earlier methods we'd often have to cut a big hole in a bone in order to get the DNA out of it. In this method, we take some hair clippings and, you know, the damage to the actual specimen is obviously quite minimal, which obviously endears us to the curators.
PALCA: Because museum curators hate to part with any of their precious specimens. The data from the mitochondrial DNA can help tell scientist about where an animal came from and provide clues about how and when it went extinct. Of course, there are limitations to using hair to find ancient DNA. The most important is that not all ancient carcasses possess hair.
But molecular anthropologist Brian Kemp says plenty of animals do and there are plenty of hair specimens in natural history museums around the world. Kemp is at Washington State University in Pullman. Suddenly, stuff that's been sitting in drawers and glass cases, sometimes for hundreds of years, takes on new importance.
Dr. BRIAN KEMP (Molecular Anthropologist, Washington State University): People have been keeping this old junk around. No one could fathom extracting DNA from a 46,000-year-old mammoth hair. And it really emphasizes the importance for careful curation.
PALCA: So you know which hairs came from which ancient beast. Kemp says we could soon have detailed genetics of a menagerie of long-extinct species.
Joe Palca, NPR News.
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