The reason that these results are so surprising is that people thought a snowball could survive in hell better than a peptide could survive the fossilization process. It has nothing to do with the stability of peptide or phosphodiester (nucleotide) bonds, which supposedly break down after a few thousand years. They hypothesize, as I understand it, that some special property of this particular fossilization of bone material was able to form a crystal matrix that protected some peptides from degrading. What's really cool is that not only are there peptides, there are fossilzed osteocytes (bone cells) in there as well.
So basically, if they can find peptides, there is no reason they cannot find nucleic acid buried in the crystal matrix. The problem is that both are likely to be very short sequences, maybe 10 or 20 units long. This isn't a problem for peptides, because with 10-20 amino acids it's much easier to identify what protein it belonged to using a mass spec. With a DNA molecule, 10-20 bases isn't going to tell you much of anything, if it was even part of a gene or just regulatory sequences. For preserved DNA to be valuable, it would need to be a long strand of a few hundred bases at least. I don't think anything like that has been found.
However, these results certainly do give one reason to hope :)
On Wednesday, July 17, 2013 1:00:53 PM UTC-4, Mega wrote:
-- On Wednesday, July 17, 2013 1:00:53 PM UTC-4, Mega wrote:
Therefore you would need to find another dinosaur bone, if it has the same peptide sequence, it would fit well.If the peptides can be conserved, can there be DNA remaining intact to some degree?Is a peptide bond more stable than nucleotide bonds?Put it the other way:
> Maybe an ancient moa-like bird used the fossil bed as a nesting site?On Wed, Jul 17, 2013 at 4:36 PM, Ashley Heath <ovici...@gmail.com> wrote:
Elsevier....! Unable to get the paper, would you contact me at ahe...@sial.com when you get a moment please?To view this discussion on the web visit https://groups.google.com/d/
On Wednesday, July 17, 2013 9:10:20 AM UTC-5, A.J. DNA wrote:Heh... opinion.--So I've been extensively researching this topic for a little side project I am considering. It's worth noting that the group led by M Schweitzer and J Asara have written quite a few papers backing up their original findings. One important aspect is that proteins were not discovered... but peptides were. The crux of the matter lies with their discovery of peptides originating from histones in a hadrosaur fossil, which as you may recall bacteria do not possess. Of course, this does not rule out contamination, but it does eliminate the most likely culprit. Here's the DOI for that paper, where they do a fantastic job backing up their results with mass spec and immunohistochemical assays.:DOI: 10.1016/j.bone.2012.10.010 (Let me know if you cant get it and I'll happily provide the pdf. Just shoot me an email.)Another important consideration is that the peptides in question share significant homologies with avian peptides. This, I imagine, would be a tough feat for peptides from, say, a fungus, to pull off. Maybe an ancient moa-like bird used the fossil bed as a nesting site? So, you know, there is room for SOME doubt, if you wanted to be difficult. But these results would certainly hold up in court. Obviously, more work needs to be done, and more peptides discovered.As you can probably tell by my post, I believe the results. The biggest question now is how common are these peptides? Does fossil preservation need to be exceptional, or can they be found in most fossils, provided you do control for contamination? This would be a big problem for any fossil that has already been dug up and is in a museum basement.If the peptides are common enough, and whole protein sequences can be determined, it's simple enough to reverse-translate the genome. As has been said though, it's still a long way off.~A.J.
On Friday, July 12, 2013 5:10:52 PM UTC-4, Mega wrote:Just saw a film on TV that T-Rex bones were found which still contained few proteins like collagen. Then I read that this is very controversial, if that is not contamination.
Then I came across this...
http://canterburyheritage.blogspot.co.at/2009/01/extinct- moa-to-be-brought-back-to- life.html
The giant bird, Moa, is relatively new extict and there should be plenty of sources for DNA... Even eggs are said to be still there.
I assume there won't be any cells any more that are still alive...? Is it possible to purify the chromosomes, insert in a living cell? I assume that it would be near-to- impossible in a diy-setting, because the DNA will be damaged at least to some degree...
However, from the legal point of view, this should be perfectly legal (while inserting GFP into E.Coli is a capital crime)...
Any opinions on this?
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