DAVID GREENE, HOST:
And we're covering everything this morning, including woolly mammoths who roamed the frozen tundra over 12,000 years ago during the last Ice Age. Their closest relative alive these days is the Asian elephant, which lives in warm, tropical forests. NPR's Nell Greenfieldboyce reports that scientists have now compared the DNA of these two mighty beasts to try and figure out how woolly mammoths got to be so, well, woolly.
NELL GREENFIELDBOYCE, BYLINE: The woolly mammoth had long, shaggy fur, a small tail and ears to minimize frost bite and a lot of fat to help stay warm.
VINCENT LYNCH: And they have this weird hump on their back, which is thought to be something like a camel hump, sort of a fat deposit that stored water and energy for the cold, dark winters.
GREENFIELDBOYCE: Vincent Lynch is an evolutionary biologist at the University of Chicago.
LYNCH: We wanted to identify the genetic changes that happened in woolly mammoths that make them mammoth-like.
GREENFIELDBOYCE: Mammoths are extinct, but thawing ice means bits of them turn up from time to time. You can even buy mammoth hair on eBay. These researchers did. Then they extracted the DNA. In the journal Cell Reports, they describe how they compared it to the DNA of Asian elephants. They found a long list of genes with mammoth-specific changes. But Lynch says here's the trouble...
LYNCH: We know that most genetic differences between species actually are neutral. They have no function.
GREENFIELDBOYCE: Still, they spotted one gene that seemed intriguing.
LYNCH: Based on what we know in humans and mice, it had three functions. It functions in sensing the external temperature. It functions in fat biology, and it functions in regulating hair growth.
GREENFIELDBOYCE: Lynch says previous studies have shown that if you disable this gene in mice...
LYNCH: They actually prefer to live in colder environments.
GREENFIELDBOYCE: The scientists wanted to see if the mammoth-specific change in this gene would alter the protein it makes and have a similar effect. And some lab experiments suggested maybe so.
LYNCH: We found that the mammoth protein was much less active. It's sort of like if you had a dimmer switch on a light that was kind of like turning down the activity of the protein.
GREENFIELDBOYCE: But Lynch says don't think you can take this information and use it to transform an Asian elephant into a mammoth.
LYNCH: You could change this one gene in an elephant and maybe make it woolly mammoth-like with respect to some things.
GREENFIELDBOYCE: Trying to re-create a mammoth in all its woolly glory would require a ton of other genetic changes, so many that scientists don't have the technology to do it. And even if it was possible, Lynch thinks they shouldn't try it. Nell Greenfieldboyce, NPR News.
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