Talk:Evidence of blood in a Tyrannosaurus bone indicates recent burial (Talk.Origins)

Very interesting controversy. I did add a couple things on AAR and the last statement. I am a layman, and don't know a lot of things about paleobiochemistry, so feel free to correct me. I have read, though, that with AAR, the L forms convert to the D forms until they are completely racemized. Though I find it strange that scientists would date it with AAR, they could use it to determine that the sample is oldish by calibrating it with C14. Of course, if accelerated decay is true, then the AAR date is totally pointless.

For the DNA section, I mentioned some potential geologically ancient DNA findings. I'm not totally sure about putting Goldenburg's magnolia leaf in there simply because it has been criticized by many people, especially because it failed the AAR test. I've been planning to email him though and ask him what he thinks about the criticisms of his findings. I opted not to include Woodward's findings because his findings in dinosaur DNA have been criticized even more than Goldenburg's work; if I remember correctly, in addition to failing the AAR test, I believe some human DNA was found in his dino bones, or something like that I don't really remember.

I said potentially geologically ancient DNA because there is another common criticism by Paabo, Willerslev, Cooper and others. Many scientists argue that all antediluvian DNA is contaminated because of the high rate of contamination. They argue that the fossils that have been found have such little DNA in them, that if any modern DNA gets in it, scientists will not be able to tell whether or not it is contaminated. They are correct; in addition, they are also correct when they argue that laboratories may have a lot of modern DNA from previous amplified DNA. However, the scientists are careful in their work, so I think you can build a cumulative case.

The only other argument that I know of is that the findings have not been replicated and that they can't survive that long. However, the very fact that there are multiple gaDNA findings is in and of itself an "independent replication". In addition, scientists have tested the DNA with AAR to see if the fossils follow the general pattern of having more Aspartic acid than Alanine and more Alanine than Valine. If I remember correctly, several findings have been replicated this way. The ancient bee has also been replicated. Thus, I think the evidence is strong enough to be used as a counter to TO's claim.

TO does raise an interesting claim though--that if YEC is true, we would find more DNA. I don't think this is necessarily true though because as the temperature rises, the DNA degrades faster. The theoretical models for the survival of DNA argue for the maximum possible time that DNA could survive, so I don't think that one could really claim that DNA findings would be more frequent. The other thing that comes to mind is that there would be a lot of heat from Noah's flood. Do you guys think that Noah's flood could have degraded a lot of the DNA from the animals?Shinydarkrai94 00:31, 23 June 2011 (PDT)

Well did a bit of research and so far as I can tell, in general, DNA finds aren't supposed to last more than a few hundred or a thousand years to be honest. Generally, DNA survival is dependent upon good preservation rather than time. In addition, it should be noted that often, DNA is trapped in cross-links, making amplification difficult without re-amplifying it repeatedly. This and the other fact would explain why DNA isn't extracted all the time from very ancient sources. Shinydarkrai94 21:08, 15 July 2011 (PDT)