Skip to comments.Ancient penguin DNA raises doubts about accuracy of genetic dating techniques
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 whats 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. Its 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.
Nun too soon ping.
but science has all sorts of built in safeguards to keep their precious dating methodologies from ever being wrong, right???
but science has all sorts of built in safeguards to keep their precious dating methodologies from ever being wrong, right???
There is a small, but very good, Arctic museum in Corvallis.
I don’t believe this crap. I bet these scientists are funded because they said that they were trying to scientifically prove global warming because of penguin turd.
"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." Exactly what we've been pointing out for years.
Excellent find Liberty1970...and you are exactly right, we have been pointing this out for years!!!
And I was under the impression that man and other life forms on this earth were only 6000 years old. Can someone help me understand how a penguin can be dated at 200,000 years old. It’s a christian thing I have trouble getting past.
Easy - Just decide how old you want it to be, and fudge and fidgit all data to fit. Happens every day.
I don’t understand how, if the samples are *older* than we thought, that means evolution moves *faster* than we thought. That seems contradictory.
If you find a 10% genetic change in a non genetic sequence between modern penguins and ancient penguins and you think it corresponds to 20,000 years; but find that instead it corresponds to 40,000 or 60,000 years - that means that the rate of change of that sequence is SLOWER than expected, not faster.
Somewhere between the actual science and this school publication someone got a little mixed up.
And even a doubling or tripling of the expected rate of accumulation of neutral mutations doesn't come close to the speed of evolution and speciation that Creationists would need for every species on Earth to have descended from those that could fit on a boat within the last few thousand years or so.
“I don't believe in evolution, except when it happens thousands of times faster than any evolutionary biologist ever suggested.” the ignorant Creationist maintains.
My friend, you’re missing the point entirely. This does not relate to the Bible or Creation v. Evolution, per se. It points out that much of the assumptions of evolutionists are faulty. Like the parable of the man who built his house upon the sand. A poor foundation leads to poor results. Or like the old computer-geek saying, Gargage In — Garbage Out.
I think this is meant to be the explaining sentence: "We now think that many genetic changes were happening that conventional DNA analysis did not capture."
To me this means that the longer time period includes heretofore undetected changes.
1) that DNA change is faster than expected.
2) that the amount of DNA change that you might expect from 20,000 years divergence is actually 40,000 years worth of divergence (i.e. the DNA change is slower than expected).
And in neither case is the evolution fast enough to satisfy the needs of Creationists who, although they actually believe in evolution thousands of times faster than evolutionary biology suggest is possible - usually say they don't believe in evolution at all.
I think it's saying that the DNA changes are faster than has been believed because there are more changes than has been believed. But it's hard to be sure with the condensed version.
· Discover · Nat Geographic · Texas AM Anthro News · Yahoo Anthro & Archaeo · Google ·
· The Archaeology Channel · Excerpt, or Link only? · cgk's list of ping lists ·
For example one could see a difference in a particular ERV shared between dogs and wolves that is X% different - and that X% difference is assumed to cover the time that dogs have diverged from wolves. The X doesn't change, it is a measured amount (for those particular sequences).
What the research is attempting to change is the amount of TIME that it would take for an X% difference to form; they say that X% that would be 20,000 years should be 40,000 to 60,000 years.
That means that the RATE of change is one half to one third as rapid as previously expected; not twice or three times as fast - as is also maintained, despite the inherent contradiction.
As I said, somewhere between the actual science and the publication of this in the school paper; someone got confused.
Not the amount of change but the number of changes.
A man who dates carbon wastes time.
The number of changes adds up to the amount of change.
A 13% divergence in an ERV sequence shared between two species that is 1000 bases long is a “number of changes” of 130.
But each change is one state of evolution. If there are many more changes than has been believed then the rate of evolution is faster than has been believed.
Are you following?
Say that previously a 10% difference in a particular DNA region between two species of a particular type and generation time (say two types of badgers) was assumed to correspond to a 10,000 year difference should be 20,000 or 60,000 BASED upon their penguin data.
The “rate of evolution” would be SLOWER, if that 10% difference took some 40,000 years instead of 10,000.
Why are we back to this? It is not a difficult concept. I thought we had moved on to EXPLAINING how they could claiming both contradictory things. Why am I having to explain the contradiction again?
I'm following you doing everything to promote your own thesis and nothing to understand the article.
Is it also my own thesis that one third is a slower rate not a faster rate?
I consider my very own thesis to be supported by the evidence and the most rudimentary mathematics, therefore anyone who disagrees with my own thesis must not be able to think their way out of a wet paper sack.
Buttering me up? I hope it’s real butter. ;-)
Let’s say that it’s been believed that you finished off 100 servings of popcorn over the past 20,000 years (hence the grey whiskers). But it’s now believed that you finished off 2,000 servings of popcorn over the past 200,000 years. The rate of change of your popcorn consumption would thereby have increased by twice.
Substitute DNA changes for popcorn servings and you have it.
I’ve suspected for some time that something isn’t quite right with our DNA science. This may just be one thing that is wrong.
It would be nice to see more things reported as hypotheses rather than conclusions. But then, they might not be reported.
So basically what they are saying is that scientists have no idea what they are doing when it comes to dating techniques. Knock me over with a feature.
Yeah, it's the jocks that get all the action.
Any good scientist understands that any conclusion is merely tentative based upon the soundness of ALL of the underlying assumptions and ALL of the observed facts, and the change of any of these will likely change the conclusion. So what you hope, actually goes unsaid because it is already known to the professional audience that reads these papers.
Sorry GGG, but you cannot disprove the theory of evolution based upon genetic mutations by asserting that someone is mistaken about the rate of mutation, asserting that because the rate is slower than previously believed evolution is disproven. Your argument is an argument for a theory of evolution, just one with the rates jiggered, sort of like claiming Einstein was wrong because the speed of light is 20% slower than everyone thought it was.
That's one reason I'm not too critical of these articles. When there is a link to an original paper, that paper is often too much to tackle for a non-professional. The article is just someone's attempt to present the material in the paper to a general audience.
==Sorry GGG, but you cannot disprove the theory of evolution based upon genetic mutations by asserting that someone is mistaken about the rate of mutation
Sorry AJ, creationist have been all over this issue for about a decade. And as per usual the evos are Johnny-come-latelies. If you want to be caught up to speed, you might consider reading the following. Pay particular attention to the date range the Evos were forced to assign to the “mitochondrial eve”:
Thanks for the ping!
Exactly what we've been pointing out for years.
Welcome aboard the evolutionary train! GGG is going to be angry with you for pointing out that you are an evolutionist!
I haven’t read beyond this post. However, I am certain some mouth-breathing half-wit has already howled that creationists by default must believe in a 6000 year old Earth.
Actually, if you take a gander at the link in #41, you will see that God’s creation is designed in such a way as to ensure that even the most ardent God-hating Evos have no choice but to confirm His handiwork.
I think what is going on is they are talking about the evolution of the penguin BEFORE the DNA samples were ‘alive’. If you push back their ages then you compress the evolution that got them to that state.
See #44 and 46. GB just called you a mouth-breathing half-wit.
Actually, after reading up to post 8, I commented -
Grizzled Bear to Liberty1970; GodGunsGuts
I havent read beyond this post. However, I am certain some mouth-breathing half-wit has already howled that creationists by default must believe in a 6000 year old Earth.
Post Reply | Private Reply | To 8 | View Replies
Note: I made my comment at post 8 before reading any further.
Then you posted -
Tuesday, November 10, 2009 10:30:53 PM · 45 of 49
ColdWater to Grizzled Bear
Then I pointed you to post 10 where hitchit made the obligatory 6000 year old Earth post.
Now ColdWater, are you finished behaving like a little girl who is compelled to tattle to Mommy? I hope some day reach puberty and are able to move beyond such behavior.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.