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Posted on 06/11/2007 10:35:44 AM PDT by blam
Ancient DNA traces the woolly mammoth's disappearance
Some ancient-DNA evidence has offered new clues to a very cold case: the disappearance of the last woolly mammoths, one of the most iconic of all Ice Age giants, according to a June 7th report published online in Current Biology.
DNA lifted from the bones, teeth, and tusks of the extinct mammoths revealed a “genetic signature” of a range expansion after the last interglacial period. After the mammoths’ migration, the population apparently leveled off, and one of two lineages died out.
“In combination with the results on other species, a picture is emerging of extinction not as a sudden event at the end of the last ice age, but as a piecemeal process over tens of thousands of years involving progressive loss of genetic diversity,” said Dr. Ian Barnes, of Royal Holloway, University of London. “For the mammoth, this seems much more likely to have been driven by environmental rather than human causes, even if humans might have been responsible for killing off the small, terminal populations that were left.”
Barnes, along with Dr. Adrian Lister of the University College London and the Natural History Museum in London and others, had earlier found evidence that bison, bears, and lions underwent major population shifts twenty-five to fifty thousand years ago. Those results came as a surprise, the researchers said, because scientists tended to think that the major environmental changes happened about fifteen to twenty-five thousand years ago, when the glaciers reached their fullest extent. The findings also offered early human hunters a potential alibi; they didn’t come on the scene in large numbers until even later.
Woolly mammoth
In search of a general pattern in the new study, Barnes and Lister’s team looked to the extinct woolly mammoth. What they found, however, was an “interesting pattern, not like those of the other species.”
Their genetic data indicate that Siberian mammoths expanded from a small base some time before sixty thousand years ago. Moreover, they found two distinct genetic groups, implying that mammoths had diverged in isolation for some time before merging back into a single population. The DNA further suggests that no later than forty thousand years ago, one of the groups died out, leaving only the second alive at the time of the mammoth’s last gasp.
“At a time when we should be very concerned about the potential extinction of many existing large mammals, studying those that occurred in the geologically recent past can provide many insights,” Lister said. “Our work, together with that of others, shows that the conditions for extinction can be set up long before the actual extinction event.”
Source: Cell Press
Manfred alias Manny the Mammoth (see “Ice Age”) has a history.
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I realize that you're having fun with this, but for the benefit of others there are diseases like this among dogs. The bitch can be infected relatively harmlessly. If she passes it to the stud dog, he can become infected and eventually sterile, potentially ending his genetic line.
There are also diseases like anthrax among cattle. I could see something like that spreading like wildfire, too.
This seems to be “Wooly Mammoth Week”
My theory is they all starved to death..........
Nah, it's an AC week for me...the heat index is 105 here.
This is just tremendously cool. I love this stuff.
Mammoth told me there’d be weeks like this.
[rimshot!]
There are reports of sitings of Woolly Mammoth in Alaska
as late as the 1800s. We find their bones all over the
place up here.
Too bad Hillary hasn’t passed anything along to hubby.
They got a sample from the scene that matches David Copperfield?
groan...
You punsters always have a handy pun.
The trick was to get them to jump off a cliff or fall in a hole.
Most of these points were gathered in a small area where large mammals gathered to eat grass, represent three cultures, and clearly indicate that the users were far more interested in cutting up meat or leather than killing large critters.
Tusk,Tusk, that’s a really bad one.
I was trunk when I posted that.
http://www.freerepublic.com/focus/f-news/1848766/posts
Even more evidence that the subject of ‘Mammoths’ is bubbling up into our conscienceness this week. There is something supernatural working here.
Something mammoth this way comes.
I woolly think you’re onto something.
that “forests caused extinction” mammoth guy:
http://www.freerepublic.com/focus/f-news/1848403/posts
“Their genetic data indicate that Siberian mammoths expanded from a small base some time before sixty thousand years ago. Moreover, they found two distinct genetic groups, implying that mammoths had diverged in isolation for some time before merging back into a single population. The DNA further suggests that no later than forty thousand years ago, one of the groups died out, leaving only the second alive at the time of the mammoth’s last gasp.”
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