Posted on 06/10/2008 1:38:12 PM PDT by blam
Woolly-Mammoth Gene Study Changes Extinction Theory
Ball of permafrost-preserved mammoth hair containing thick outer-coat and thin under-coat hairs. Credit: Stephan Schuster lab, Penn State
A large genetic study of the extinct woolly mammoth has revealed that the species was not one large homogenous group, as scientists previously had assumed, and that it did not have much genetic diversity.
"The population was split into two groups, then one of the groups died out 45,000 years ago, long before the first humans began to appear in the region," said Stephan C. Schuster, associate professor of biochemistry and molecular biology at Penn State University and a leader of the research team. "This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction." The discovery will be published later this week in the early online edition of the Proceedings of the National Academy of Sciences (PNAS).
The research marks the first time scientists have dissected the structure of an entire population of extinct mammal by using the complete mitochondrial genome -- all the DNA that makes up all the genes found in the mitochondria structures within cells. Data from this study will enable testing of the new hypothesis presented by the team, that there were two groups of woolly mammoth -- a concept that previously had not been recognized from studies of the fossil record.
The scientists analyzed the genes in hair obtained from individual woolly mammoths -- an extinct species of elephant adapted to living in the cold environment of the northern hemisphere. The bodies of these mammoths were found throughout a wide swathe of northern Siberia. Their dates of death span roughly 47,000 years, ranging from about 13,000 years ago to about 60,000 years ago.
Schuster and Webb Miller, professor of biology and computer science and engineering at Penn State, led the international research team, which includes Thomas Gilbert at the University of Copenhagen in Denmark and other scientists in Australia, Belgium, France, Italy, Russia, Spain, Sweden, the United Kingdom, and the United States. The team includes experts in the fields of genome evolution, ancient DNA, and mammoth paleontology, as well as curators from various natural-history museums.
Another important finding for understanding the extinction processes is that the individuals in each of the two woolly-mammoth groups were related very closely to one another. "This low genetic divergence is surprising because the woolly mammoth had an extraordinarily wide range: from Western Europe, to the Bering Strait in Siberia, to Northern America," Miller said. "The low genetic divergence of mammoth, which we discovered, may have degraded the biological fitness of these animals in a time of changing environments and other challenges."
Our study suggests a genetic divergence of the two woolly-mammoth groups more than 1-million years ago, which is one quarter the genetic distance that separates Indian and African elephants and woolly mammoths," Miller said. The research indicates that the diversity of the two woolly-mammoth populations was as low centuries ago as it is now in the very small populations of Asian elephants living in southern India. "The low genetic divergence of the elephants in southern Indian has been suggested as contributing to the problems of maintaining this group as a thriving population," Schuster said. Intriguingly, the mitochondrial genomes revealed by the researchers are several times more complete than those known for the modern Indian and African Elephants combined.
Whereas studies before this research had analyzed only short segments of the DNA of extinct species, this new study generated and compared 18 complete genomes of the extinct woolly mammoth using mitochondrial DNA, an important material for studying ancient genes. This achievement is based on an earlier discovery of the team led by Miller, Schuster, and co-author Thomas Gilbert, which was published last year and that revealed ancient DNA survives much better in hair than in any other tissue investigated so far. This discovery makes hair, when it is available, a more powerful and efficient source of DNA for studying the genome sequences of extinct animals. Moreover, mammoth hair is found in copious quantities in cold environments and it is not regarded as fossil material of enormous value like bone or muscle, which also carries anatomical information.
"We also discovered that the DNA in hair shafts is remarkably enriched for mitochondrial DNA, the special type of DNA frequently used to measure the genetic diversity of a population," Miller said. The team's earlier study also showed that hair is superior for use in molecular-genetic analysis because it is much easier than bone to decontaminate. Not only is hair easily cleaned of external contamination such as bacteria and fungi, its structure also protects it from degradation, preventing internal penetration by microorganisms in the environment.
An important aspect of the new study is that the hair samples it used had been stored in various museums for many years before being analyzed by the researchers, yet the scientists were able to obtain lots of useful DNA from them. "One of our samples originates from the famous Adams mammoth, which was found in 1799 and has been stored at room temperatures for the last 200 years," Schuster said. This research technique opens the door for future projects to target interesting specimens that were collected a long time ago and are no longer available from modern species, the scientists said. Even the molecular analysis of entire collections seems now possible, an effort that the team calls "Museomics."
"We plan to continue using our techniques to untangle the secrets of populations that lived long ago and to learn what it might have taken for them to survive," Schuster said. "Many of us also have a personal interest in learning as much as we can about how any species of large mammal can go extinct."
Source: Penn State
GGG Ping.
Absolutley amazing that these fellas remained after 47000 years!
My freezer goes out of power for like one day and all the meat is ruined.
Those Siberian freezers must be sumthin else!
I mean even if I leave a steak in there for oh...say, 6 months, it’s ruined.
47000 years?
just dam!
Hi blam,
Like we’ve been saying... Take that, Jared Diamond and other PC “researchers!”
If global climate changed and humans were not the cause, then that means that climate change is normal and animal extinctions are normal.
“This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction.”
Of course, the humans had to be to blame for the climate change, so it was the humans who did them in anyway.
Those Woolly Mammoths couldn't by carbon offsets fast enough, I guess...
Sssshhhhhh! You can't say that!
Funny how three of us picked up on the same sentence. Anyway, not being caused by humans, it had to be because of the Mammoth methane gas releases. Yeah, that’s it :)
They didn't mention the other catch phrase,..
Habitat Destruction
There you go, see what happens when you don’t value diversity!!!!
Questions that I have asked and received no answers:
1. In the frozen place that they were found, what was growing that they could eat?
2. If they froze so quickly that they were preserved along with their food how quick did the climate have to change for this to happen? (My freezer does not do that)
“”This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction.””
That’s a pretty sweet argument for hunting and from a scientist. I realize that’s not the conclusion he was probably going for. Since the Libs say we’re doomed because of global warming and disease is rampant, we might as well go hunt the critters before they all drop dead.
My neighbor here in central Texas
found a 12 foot mammoth tusk in his yard.
I saw it. He sold it for $200.
It is kind of a holy grail for many scientists to figure out a way to bring back the woolly mammoth. They not only have figured out the process, but a preserve has been set aside in Siberia in case it works.
I gather they intend to start with a mammoth-elephant hybrid, then over several generations, to replace the elephant DNA with mammoth DNA, eventually creating the closest thing to a pure mammoth.
http://www.luckyninja.com/flash/elephants.swf
Could be from an extinct Republican.
Innerestin’
“There must have been a quick climate change as some that have been found frozen also have the food in their bellies that they had just eaten.
Questions that I have asked and received no answers:
1. In the frozen place that they were found, what was growing that they could eat?
2. If they froze so quickly that they were preserved along with their food how quick did the climate have to change for this to happen? (My freezer does not do that)”
To answer your questions as best I can...
1. Think permafrost, Soil on top of perpetually frozen ground. The mammoths’ territory was apparently relatively lush grasslands (now called the “mammoth steppe,” for which there is no exact counterpart today).
2. There’s a popular conception of mammoths being quick-frozen and perfectly preserved in a single sudden catastrophic event, but it was messier than that. There are very few intact and well-preserved specimens (the best are a couple of babies, more easily frozen due to their small size), and many are in various states of decomposition or eaten by carnivores or scavengers. Many frozen mammoths were probably buried by mudslides, which then froze around them, or fell through thin layers of ground over mudflows. Falling through thin river ice and drowning was another way to die and freeze. These were probably rare events at any one time, and relatively rare even over long periods, so there aren’t a whole lot of well-preserved specimens, but they occasionally did happen.
There are stories of Russians having feasts of mammoth meat, but these seem to be legends as reports are that they aren’y so well-preserved as all that.
If man didn't cause the first extinction, who are the doofus dingbats gonna blame for the poor critters' demise?
The next thing these neo-con “scientists” will tell us is that humans didnt cause the Ice Age! Fascists! /s
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