Dinosaur blood?

Like most claims of detection of ancient biomolecules in the millions of years old range, I am extremely skeptical of this one. The amber DNA studies for example were never reproducible and in the case of one, it was discovered to be an artifact (if not fraud).Gutierrez G, Marin A.
The most ancient DNA recovered from an amber-preserved specimen may not be as ancient as it seems.
Mol Biol Evol. 1998 Jul;15(7):926-9.In any case, the presence of intact and detectable (using antibodies) heme compounds from an 80 My old fossil sounds more like contamination of the fossil than authentic endogenous protein breakdown products. If you look at the best studied ancient proteins they come from mammoths that were only several tens of thousands of years old and the amount of endogenous protein detected was about 2% of what you would expect for a modern sample.Science. 1980 Jul 11;209(4453):287-9. Related Articles, LinksMammoth albumin.Prager EM, Wilson AC, Lowenstein JM, Sarich VM.Serum albumin was detected immunologically in muscle from a mammoth that died about 40,000 years ago. Rabbits injected with ground mammoth muscle produced antibodies that react strongly with elephant albumin, weakly with sea cow albumin, and still more weakly or not at all with other mammalian albumins. Since elephant albumin elicited antibodies with the same specificity, some of the surviving mammoth albumin molecules evidently have antigenic sites identical to those on native elephant albumin. Much of the mammoth albumin has, however, undergone postmortem change. The small amount of soluble albumin extractable from mammoth muscle is heterogeneous in size, charge, and antigenic properties.It is hard to imagine that an 80 My old fossil would show preservation anywhere in the range of a permafrost frozen specimen like the Dima mammoth which is only about 40 Ky old. So until the dinosaur data is independently reproduced I for one would list it as a highly tentative result given the frequency with which these types of experiments tend to turn out false.

Hi Taz,
Great to see you back on the forum!
Protein racemization levels do seem to correlate with DNA preservation in ancient materials (won't call them fossils since they are not fossilized). However, this is on a scale of tens of thousands of years and not millions. The amber studies demonstrated reasonably low racemization levels for the amber inclusions yet without an exception, none of the DNA results could be reproduced and the reference I include implies something a bit more sinister for one of the participating groups. That aside, having worked in a museum for a few years, the fossils get handled A LOT. In addition, many are treated with various preservatives, paints, etc. many of which are organic based or include animal/insect proteins. It is still formally possible that the immune reaction was generated by a contaminant of the handled fossil as opposed to endogenous protein residue. Another cautionary note, the biggest fiasco in ancient DNA was the report of DNA sequences from a dinosaur bone. It turned out to be a human nuclear insertion copy of mitochondrial cytochrome b. Even though fairly stringent controls were observed. I recognize that proteins can be much more stable than nucleic acids. I am currently working with prions and you cannot get rid of the damn things. But 80 My proteins will necessarily require an extreme burden of proof.

Hi Dr.GH,
Nice articles. I have met Schweitzer a couple of times at ancient DNA meetings (she dabbles in nucleic acids as well). It is a complete mis-representation (as you point out) by creationists to go from extremely preliminary evidence for modified, blood derived, immuno-reactive compounds which may or may not originate from the fossil in question to their claim that actual blood was retrieved from a T. rex. Just goes to show how deeply dishonest many creationists are.

That could well be the case in some instances. However, the creationists who write books on the subject including dino blood, are dishonest if they claim to have read the articles on which they base their books and then continue without revising or noting their error to repeat a completely false set of statements not in the original papers. This goes beyond simple ignorance.I think the sad thing is that the media does not do much better at portraying scientific findings or maintaining accurate accounts of scientific studies than many a creationist.