Posted on 11/10/2009 10:54:53 AM PST by decimon
CORVALLIS, Ore. - Penguins that died 44,000 years ago in Antarctica have provided extraordinary frozen DNA samples that challenge the accuracy of traditional genetic aging measurements, and suggest those approaches have been routinely underestimating the age of many specimens by 200 to 600 percent.
In other words, a biological specimen determined by traditional DNA testing to be 100,000 years old may actually be 200,000 to 600,000 years old, researchers suggest in a new report in Trends in Genetics, a professional journal.
The findings raise doubts about the accuracy of many evolutionary rates based on conventional types of genetic analysis.
“Some earlier work based on small amounts of DNA indicated this same problem, but now we have more conclusive evidence based on the study of almost an entire mitochondrial genome,” said Dee Denver, an evolutionary biologist with the Center for Genome Research and Biocomputing at Oregon State University.
“The observations in this report appear to be fundamental and should extend to most animal species,” he added. “We believe that traditional DNA dating techniques are fundamentally flawed, and that the rates of evolution are in fact much faster than conventional technologies have led us to believe.”
The findings, researchers say, are primarily a challenge to the techniques used to determine the age of a sample by genetic analysis alone, rather than by other observations about fossils. In particular, they may force a widespread re-examination of determinations about when one species split off from another, if that determination was based largely on genetic evidence.
For years, researchers have been using their understanding of the rates of genetic mutations in cells to help date ancient biological samples, and in what’s called “phylogenetic comparison,” used that information along with fossil evidence to determine the dates of fossils and the history of evolution. The rates of molecular evolution “underpin much of modern evolutionary biology,” the researchers noted in their report.
“For the genetic analysis to be accurate, however, you must have the right molecular clock rate,” Denver said. “We now think that many genetic changes were happening that conventional DNA analysis did not capture. They were fairly easy to use and apply but also too indirect, and inaccurate as a result.”
This conclusion, researchers said, was forced by the study of many penguin bones that were well preserved by sub-freezing temperatures in Antarctica. These penguins live in massive rookeries, have inhabited the same areas for thousands of years, and it was comparatively simple to identify bones of different ages just by digging deeper in areas where they died and their bones piled up.
For their study, the scientists used a range of mitochondrial DNA found in bones ranging from 250 years to about 44,000 years old.
“In a temperate zone when an animal dies and falls to the ground, their DNA might degrade within a year,” Denver said. “In Antarctica the same remains are well-preserved for tens of thousands of years. It’s a remarkable scientific resource.”
A precise study of this ancient DNA was compared to the known ages of the bones, and produced results that were far different than conventional analysis would have suggested. Researchers also determined that different types of DNA sequences changed at different rates.
Aside from raising doubts about the accuracy of many specimens dated with conventional approaches, the study may give researchers tools to improve their future dating estimates, Denver said.
Collaborators on the research included scientists from OSU, Griffith University in Australia, the University of Auckland in New Zealand, Massey University in New Zealand, University of North Carolina in Wilmington, the Scripps Research Institute, and Universita’ di Pisa in Italy.
The studies were supported by the National Science Foundation, National Geographic Society, and other agencies. About the OSU College of Science: As one of the largest academic units at OSU, the College of Science has 14 departments and programs, 13 pre-professional programs, and provides the basic science courses essential to the education of every OSU student. Its faculty are international leaders in scientific research.
All girls and also the grandkids.
Then I continued reading. And then you posted #44 nine hours and seven minutes AFTER H posted his #10.
I've repeated time and time again, I hadn't read beyond post #8 before I posted my response to #8. Therefore I hadn't read # 10 before I posted. This means the posting times are irrelevant.
Are you naturally this clueless or is it something you work at chemically? What the hell do you do for a living? There's no way anyone would pay you three figures for your obvious lack of comprehension skills. If you somehow achieved a position of any importance you would have soon lost it after a few days of piss poor performance. You've already proved yourself a hypocrite. Now you've proved yourself a liar as well.
You had nine hours and seven minutes to read #10 before posting #44.
I am a Nuclear Engineer and right now I am working on DCS upgrades. I used to work for a major NSSS vendor designing and testing nuclear power plants. Now I am work as a contractor at plants both in and outside the US.
BTW, the nuclear industry requires a very thorough background check and behavior monitoring program.
Again, I read post #8 and responded before I read any further. Call me irresponsible, but I chose to post before reading any further. It's called freedom of choice.
Oddly enough, I didn't think I need to read the entire thread before posting. I have that option.
Do you think I had an obligation to read further before I post. If that's the case it's your problem and you have control issues. I think you can get a medication for that as well.
At least I read all of post #8 before responding.
You can't even be bothered to read an entire post before responding, hypocrite. By the way, if you hold yourself to the same standards you hold others, you owe GGG an apology.
I don't think you'll apologize. You strike me as too much of a hypocrite and coward.
Hey Bro! I apologize.
BTW, the nuclear industry requires a very thorough background check and behavior monitoring program.
I doubt that's true; but if it is, you should probably lay off the crack cocaine and bong water.
Are you going to apologize to GGG? You committed the same transgression you accused me of doing. If you can't do that, why should any of us believe anything else you post?
It's true. Feel free to quiz me.
Are you going to apologize to GGG?
I did. Please read the posts. I pinged it to you only a minute or so after you said I wouldn't. Would you like a time line in military time?
CW uses “bro” to get under my skin, as I have already explained to him that since we do not share the same mother, and seeing how he is not born again, we are not “bros” no matter which way he choses to slice it. And that is precisely why he keeps calling me “bro.” Just thought I’d clue you in on CW’s phony apology.
I hope it’s not true! What a scary thought!!!
My apology was entirely sincere.
http://www.freerepublic.com/focus/chat/2383168/posts?page=127#127
before I read your 126.
See how things work?
Frankly, I don't give a Rat's ass what you do for a living; however, if you are truly a Navy veteran as you claim then I thank you for your service. Your apology to GGG earned a small measure of my respect regardless of the value you attach to it.
God bless you and good night.
It's true. Do you live near the plant I am working at now?
USS Puffer SSN-652 and USS Enterprise CVAN-65. Have a good night.
Lucky for my piece of mind, seeing how you are a known liar, I don’t believe for a moment that you are an engineer of any sort, let alone a nuclear engineer.
GGG,
I view the term "Bro" as a colloquialism. I like to avoid getting hung up on words. Liberals are hypersensitive about words. This is why they try to attack conservatives with the "tea-bagger" slur.
As Christians, our Savior expects us to act as his ambassadors in the world. I think you would make great gains by accepting CW's apology at face value. At best, he may become more apt to give you a fair hearing. At worse, your kindness "heaps burning coals upon his head." I find that really cool!
Pettiness is beneath you. I know you're a bigger man than this. I suggest you accept his apology at face value.
CW,
If GGG doesn't like being called "Bro," perhaps it would be civil for you not to call him "Bro." Thanks for a good fight. I hope you had as much fun as I.
A. Grizzled Bear
If escaping the truth lets you sleep better, fine.
There is a larger story behind the whole “bro” thing, but it’s not really important enough for me to explain at the moment. Suffice it to say, CW used the word “bro” to turn his apology into a non-apology.
I did! I only call him Bro once in a while to make sure he is awake. I don't think he really minds. It goes back aways when he said we were only brothers if I had been saved. Since I had, I started calling him Bro.
Come on. You know me better than that! You are just trying the wedge strategy. You know that I use it to get your attention, particulary like this where I wanted to make sure you knew it was to you.
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