Posted on 11/13/2002 1:16:37 PM PST by dead
The first complete sequencing of protein from a fossil bone suggests that proteins can survive for millions of years - long enough to probe the evolution of many extinct species, including the ancestors of modern humans.
For many years, biologists have deduced evolutionary relationships from the visible features of living animals and fossils. Molecular biology has given them a new tool for living animals - comparing DNA sequences. However, DNA survives for only a short time after death, so paleontologists have been limited to comparing the shapes and sizes of the bones of extinct species.
But analyzing ancient proteins now gives them a new option, says Christina Nielsen-Marsh of the University of Newcastle, because their amino acid sequences reflect genetic codes.
The big advantage of proteins is their stability in suitable environments. Pieces of DNA large enough to sequence using sensitive amplification techniques can survive for 100,000 years in permafrost. But osteocalcin, a structural protein that bonds directly to the minerals of bone, lasts much longer.
Matthew Collins, also at Newcastle University, estimates that osteocalcin can survive for more than 100 million years at 0 °C, and for some 10 million years at 10 °C. That would be long enough to look back some six or seven million years to the last common ancestor of humans and chimpanzees.
Exact match
To show the potential of their technique, Nielsen-Marsh and colleagues sequenced the amino acids in osteocalcin extracted from bones of the extinct steppe bison (Bison priscus) found in permafrost in Siberia and Alaska. Both bones are a minimum of 55,000 years old, the limit of carbon dating.
The complete sequences of amino acids exactly matched that of the modern bison (Bison bison). They differ by a single amino acid from modern cattle, which are thought to have diverged from bison at least a million years ago. Previous work has detected - but not isolated or sequenced - proteins in 120 million year old dinosaur bone.
Although osteocalcin sequences diverge slowly, they can probe evolution over millions of years. "Human evolution, is the most exciting of the possibilities," says Peter Hauschka of the Harvard Medical School, US, who worked with Nielsen-Marsh. Osteocalcins differ by a few amino acids in humans, chimps and orangutans, he says, so they could help identify the nearest living relatives of suitable fossils.
Hominid fossils are few and far between, and it could be hard to persuade anthropologists to give them up for the destructive analysis. Yet teeth also contain osteocalcin, and they are much more common fossils.
Osteocalcin itself may not be able to determine the puzzling lineages of australopithecines and humans over the past two million years, but the method could be applied to other proteins that might give a clearer picture.
Journal reference: Geology (vol 30, p 1099)
Even back then, there was far more private than public funding. Just for the heck of it, try finding out who funded the development of the first polio vaccines sometime.
But that's neither here nor there, really. More to the point, complaining that those who produce potentially valuable knowledge are no longer willing to give it away for free is akin to complaining that farmers are not willing to give their crops away for free - do you complain about the fact that farmers wish you to pay for their products when you find yourself in the produce section of your supermarket? If not, why not? What is the essential moral difference between those two cases?
The point I'm making is that in America people used to have a mindset built around can do kind of thinking. Empowerment. The ability of the individual to make a difference. The desire for individuals to make a difference. (That's why hundreds or even thousands of "random" people struggled through some hairy math to learn about an obscure thing like electricity a hundred years ago...)
The difference between now and then is that much of cutting-edge science is bigger and more expensive now than it was a hundred years ago. Creating a theory may still require nothing more than a pencil and paper, but testing those theories requires things like gene sequencers and particle accelerators and other gadgets that have long since passed beyond the reach of the individual researcher toiling in the solitude of his own basement.
So then the question is, who picks up the tab? And shouldn't the people who pick up the tab, and thereby absorb the risk of failure, have some claim to the rewards?
Heck, even if you aren't concerned by the narrowing of society at large, doesn't the narrowing of FR worry you? Just a couple of years ago, the discussions here were vastly wider and vastly more interesting that what we have today.
Why should it worry me? You know what you get when you are here, and if it offends us, we are free to take our opinions elsewhere. Whether the present trends are a good idea is neither here nor there - it is not my decision to make about FR, nor is it yours. And the only recourse we have in the event we disagree is the same recourse we always have - to vote with our feet. Would I do things differently were I running the show? Probably, but I'm not running the show, am I?
But, still, my real concern isn't the narrowing of society and the narrowing of forums like FR (though such things worry me). My real concern is the narrowing of modern minds, as people actually start to prefer situations like the present, as opposed to more open and interesting situations as they used to be.
FR is not the sum total of the real world, nor is it the sum total of the internet. People who wish to have different discussions will find different outlets, and people who prefer insular communities will find insular communities. Decry the pitfalls of that all you like - Cass Sunstein certainly does - but the cure is infinitely worse than the disease. Ultimately, you will find yourself in the rather dificult position of arguing that less choice is better than more choice, which is not an argument that most people are amenable to.
Hey, that's great - something we agree on. I happen to think that taxpayer-funded research should be in the public domain also. But the trouble is, you're shifting your argument now - how, precisely, are taxpayer-funded researchers at public institutions beholden to a "handful of CEOs" who dictate when and where they may or may not publish?
My only point which started this whole discussion -- for better and worse -- was that the kind of machinations which ultimately end up narrowing discussions (giving participants less choice rather than more) in a forum like FR provide an interesting object lesson to understanding the kind of machinations which are happening at larger scales in society in general.
Perhaps. But the narrowing of a particular forum is symptomatic of the increase in the number of available fora, don't you think? FR's too narrow for you lately? There's lots of other places you can be, including places with a wider range than this.
Of course, one might suggest that the way this discussion has wandered afield belies the contention that this forum is necessarily narrower than it used to be ;)
I've got to go watch tennis, and the special edition of Lord of the Rings.
Well, now I'm mildly jealous - I haven't picked up the special edition yet :^)
Sure they would. The darn data keeps on coming & coming: More genes from more species keep getting added to the public databases. The mutation of individual genes is random, and some parts of chromosomes mutate faster than others, so you can find outliers for any species comparisons you examine. Creationists love outliers. They're their bread & butter. They're what convince creationists that evolution is all a big House O' Cards.Nice chart. Of course this all assumes that the common ancestor exists. When you start with the result, it's not as hard to find an equation that works. As the article stated:
Biologists have addressed this problem by looking at more and more genes.
Had the single gene shown what the biologists already assumed, they would never have looked at the 50. If it had taken 100, 200 or 3000 genes, then they would have continued until they recieved the desired result.
As I understand it, gene comparisons had great successes initially, but it was later that the caveats & exceptions started cropping up, throwing the molecular clock hypothesis into doubt. But as more and more genes get sequenced, the bell curves come into focus and the outliers are revealed for what they are: The thin edges of the bell curve. And lo & behold, those bell curves DO confirm the fossil record after all!
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.
