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 didnt come on the scene in large numbers until even later.
Woolly mammoth
In search of a general pattern in the new study, Barnes and Listers 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 mammoths 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
Sorta sounds like a possible immune deficiency problem in 1 population after the (re)merging.
Amazing what geneticists can do!
Pretty cool stuff.
AIDS from Gay Wooly Mammoths?........
no second hand smoke killed em.
no the Masturbatordon never reproduced for some reason.
bump
In light of this, perhaps humans should be added to the endangered list. Extinction looms.
Victims of global warming when the glaciers melted.
Perhaps it was Onan, The Barbarian...........
Our work, together with that of others, shows that the conditions for extinction can be set up long before the actual extinction event.
Gee, just like the Democratic party....
As for the wooly mammoth, maybe they made for a nice BBQ once you scraped off the wooly part. How tough could it be to kill one of these slow moving animals for a bunch of guys with spears?
It actually could have been a form of VD that left the unadapted population sterile. It wouldn't have had to kill them. How many years would it take for a disease like that to effectively cap 1 branch of the family?
Someone postulated that maybe only a few were actually killed by man. They’d kill one and talk about for the next 20 years..........
Where would a wooly mammoth get VD? Off a toilet seat?..........
Oh, oh. Dr. Barnes is gonna be in big trouble with Big al[gore]. Doesn't he know that it's always the humans' fault? I mean, how the heck are you going to enact cumbersome regulations stifling the liberty of human beings if animals insist on going extinct all by themselves?
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Posted on 10/05/2005 2:47:27 AM EDT by planetesimal
http://www.freerepublic.com/focus/news/1496844/posts
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http://www.freerepublic.com/focus/news/1503957/posts
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http://www.freerepublic.com/focus/news/1287848/posts
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http://www.freerepublic.com/focus/f-news/1834769/posts
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http://www.freerepublic.com/focus/f-news/1836898/posts
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http://www.freerepublic.com/focus/f-news/1837610/posts
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Eureka Alert
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http://www.freerepublic.com/focus/f-news/1838660/posts
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http://www.freerepublic.com/focus/f-news/1840136/posts
the latest such topic:
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Posted on 06/11/2007 1:11:38 PM EDT by Neville72
http://www.freerepublic.com/focus/f-news/1848385/posts
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