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Molecular Analysis Supports Controversial Claim for Dinosaur Cells

The views expressed are those of the author and are not necessarily those of Scientific American.


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Do fossils of dinosaurs, such as Tyrannosaurus rex, contain soft tissues? Image: ScottRobertAnselmo, via Wikimedia Commons

RALEIGH—Twenty years ago, paleontologist Mary Schweitzer made an astonishing discovery. Peering through a microscope at a slice of dinosaur bone, she spotted what looked for all the world like red blood cells. It seemed utterly impossible—organic remains were not supposed to survive the fossilization process—but test after test indicated that the spherical structures were indeed red blood cells from a 67-million-year-old Tyrannosaurus rex. In the years that followed, she and her colleagues discovered other apparent soft tissues, including what seem to be blood vessels and feather fibers. But controversy accompanied their claims. Skeptics argued that the alleged organic tissues were instead biofilm—slime formed by microbes that invaded the fossilized bone.

Schweitzer and her colleagues have continued to amass support for their interpretation. The latest evidence comes from a molecular analysis of what look to be bone cells, or osteocytes, from T. rex and Brachylophosaurus canadensis. The researchers isolated the possible osteocytes and subjected them to several tests. When they exposed the cell-like structures to an antibody that targets a protein called PHEX found only in bird osteocytes* (birds are descended from dinosaurs), the structures reacted, as would be expected of dinosaur osteocytes. And when the team subjected the supposed dinosaur cells to other antibodies that target DNA, the antibodies bound to material in small, specific regions inside the apparent cell membrane.

Furthermore, using a technique called mass spectrometry, the investigators found amino acid sequences of proteins in extracts of the dinosaur bone that matched sequences from proteins called actin, tubulin and histone4 that are present in the cells of all animals. Although some microbes have proteins that are similar to actin and tubulin, the researchers note that soil-derived E. coli as well as sediments that surrounded the two dinosaur specimens failed to bind to the actin and tubulin antibodies that bound to the extract containing the apparent osteocytes.

Schweitzer and her collaborators detailed their findings in a paper released online October 16 in the journal Bone and in a talk given October 17 in Raleigh at the annual meeting of the Society of Vertebrate Paleontology. “Here’s the data in support of a biofilm origin,” Schweitzer said in her presentation as she showed a blank slide. “We haven’t found any yet.”

 

*Update, Oct. 20, 2012, 11:24 a.m.: Mary Schweitzer emailed me to clarify a point that did not come across in her talk. “PHEX is actually found in many taxa.  However proteins have thousands of antibody binding sites on them.  Some antibodies that bind to epitopes shared among groups  are broadly cross reactive.  Ours, OB 7.3 was selected for only one epitope out of thousands, and that epitope is, so far as it has been tested by the primary researchers, only reactive to osteoctyes from birds.  It has been tested against bird osteoblasts, cells on the same lineage as osteocytes, and does  not react, and it does not react with osteocytes from non avian taxa tested.   So it is the selective specificity of the antibody for bird osteocytes that is important.  We are not saying birds and dinos are the only ones that have the protein, but because the sequence is inherited, it has different ‘shapes’ in each group and the ‘shape’ this antibody binds seems to be unique to bird osteocytes in living taxa.”

Kate Wong About the Author: Kate Wong is an editor and writer at Scientific American covering paleontology, archaeology and life sciences. Follow on Twitter @katewong.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Quantumburrito 5:13 pm 10/18/2012

    Haven’t read the paper but I am sure they have looked at possible contamination which could be the biggest problem in these cases.

    Link to this
  2. 2. tharter 9:36 pm 10/18/2012

    Oh, there will be a LONG list of scenarios people will suggest to explain this. Honestly it IS incredibly amazing. Just random thermal degradation of biomolecules over 5 dozen megayears is pretty tough. It is going to take a lot of very careful work to write this into the consensus view, as it should. It is VERY cool, but to be sure is going to be HARD.

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  3. 3. tharriss 10:53 am 10/19/2012

    If you have red blood cells and other soft tissues, did the DNA survive too?

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  4. 4. Evolutionary Routes 10:59 am 10/19/2012

    Although I was initially quite skeptical of the research years ago, Schweitzer’s team has really buttoned up their case in favor of the endogeneity argument based upon the multiple lines of molecular biological and spatial distributional evidence of organic molecules within osteocytes, presented at the SVP annual meeting in Raleigh. Fascinating material and implications.

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  5. 5. Bird/tree/dinosaur/etc. geek 12:31 pm 10/19/2012

    Awesome. Now we just need to find some idiot with cloning technology, and we can have “Jurassic Park”.

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  6. 6. Plain-2009 1:12 am 10/21/2012

    That is exactly what I was thinking about, a Jurassic Park. The subject matter seems to be kind of a little complicated. Of course this matter should be handled with extreme care. If these nice people have gotten handle of dinosaur’s cells they should have the greatest care not to lose them. It seems it is difficult to get hold of dinosaur’s cells.I can assume it is difficult to find dinosaurs cells. And if we have gotten dinosaur’s cells we people (not experts in the field)obviously say, “Ah! we have DNA”. And if we have DNA we can bring back to life the old dinosaurs. It may not be advisable to bring back to life a Neanderthal or a Denisovan but a dinosaur falls into a different category. Of course it is a complex matter. I have not clear idea if we have a DNA we may be able to bring back to life a creature. I have no idea how the atmosphere was when the dinosaurs existed and other conditions of the environment. I have no idea if it is a good thing to bring back to life a dinosaur. If that is possible we should star collecting DNA of every creature in danger of extinction (including us). All these is very amazing and looks like science fiction becoming reality. Research should continue even if we have to decide later whether we bring back to life our cousins (Neanderthals, Denisovans, and may be others kinfolks) or the dinosaurs. Excuse me if I deal with the subject matter lightly or probably disrespectfully, but that is not my purpose, of course.

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  7. 7. Plain-2009 1:21 am 10/21/2012

    Half as a joke and half seriously. Here where I am living we are having trouble with the bears that insist in walking down the streets, imagine a dinosaur!(I know may be some people have trouble with tigers and who knows what else!) Anyway we should preserve Nature from now and from the past.

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  8. 8. Stuart Bruff 2:56 am 10/21/2012

    “Half as a joke and half seriously. Here where I am living we are having trouble with the bears that insist in walking down the streets, imagine a dinosaur!(I know may be some people have trouble with tigers and who knows what else!)”

    … well, at least the bear problem will go away with a couple of T Rex about.

    Although, on second thoughts, think of the income from filming rights to Growling Grizzly Bear v Vicious Velociraptor. Breed red-headed pachycephalosaurs and let the local bulls loose on them (I guess we’d have to convert the bulls into trichromats as well). And maybe we could finally answer the age-old question of why the Compsognathus crossed the road.

    Perhaps you’re right, though. Tyrannosaurs raiding the garbage bins might be a bit of a nuisance.

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  9. 9. Bird/tree/dinosaur/etc. geek 1:30 pm 10/21/2012

    …or hadrosaurs eating people’s gardens instead of deer.

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  10. 10. Bora Zivkovic 1:41 pm 10/21/2012

    This is one of the hot (and controversial) areas of research in paleontology. But, just because one can detect DNA (and protein) in dinosaur fossils, does not mean that the DNA is preserved well enough to be of any use, e.g., for cloning. A recent study shows that DNA has quite a short half-life of only about 512 years:
    http://www.scientificamerican.com/article.cfm?id=dinos-dna-demise-genetic-material-512-year-half-life

    Link to this
  11. 11. Bird/tree/dinosaur/etc. geek 2:36 pm 10/21/2012

    Oh, don’t be a spoilsport. [joke]

    Seriously, though, if you could bring back any one extinct species, would you really bring back a 40-foot predator with teeth the size of bannanas?

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  12. 12. Plain-2009 2:43 am 10/22/2012

    You have absolutely no idea whatsoever to what extent I appreciate your extremely good humor (Stuart Bruff – Bird/tree/dinosaur/etc. geek). I have not laugh loud that much in ages. And on the other hand the irony is that you are absolutely correct.
    Extremely interesting the reference given by Bora Zivkovic. The chances of bringing back to life extinct creatures (especially if they disappear long ago) seem slim.
    I read the article in a hurry and it seemed that they had found cells of dinosaurs. I concluded, “Ah, if they have cells they have DNA. And if they have DNA they (or someone) can re-create the creature”.
    The question of Tharris was the correct one. It seems that the answer is given by Bora’s reference.
    Reading again the article in a hurry; nowhere it says they have DNA.
    Anyway it is extremely interesting. It is still not very clear to me if gathering information from different sources one day we may reconstruct the DNA of dinosaurs. But chances seem slim.
    Thanks a lot to Bora Zivkovic.
    Actually last week coincidentally I also laugh a lot on a different incident.

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  13. 13. Bird/tree/dinosaur/etc. geek 8:06 am 10/22/2012

    “”"Actually last week coincidentally I also laugh a lot on a different incident.”"”

    The creationist House Science member, perhaps? Or is that more of a run-away-screaming sort of thing.

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  14. 14. tacitus5 5:07 pm 10/22/2012

    I read the article Bora Zivkovic refers to (http://www.scientificamerican.com/article.cfm?id=dinos-dna-demise-genetic-material-512-year-half-life) a few days ago, and I’m totally aware that nobody claims here to have DNA from T.rex bones but I get the impression that these two articles / research groups are diametrically results in some way. I do not doubt that the “512-year-half-life” of genetic material for use of sequencing and/or cloning is correct, but the article here on SA.com gives no hint what kind of bonds are broken in DNA and by what chemical mechanism. So I definitely believe it is far too early to claim “a study of fossils found in New Zealand is laying the matter to rest — and putting paid to hopes of cloning a Tyrannosaurus rex.”

    Let’s wait and see what comes next – when I was at university (1980s) no decent biochemist believed that it could one day soon be possible to sequence meaningful parts of the neaderthal man’s genes …

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  15. 15. Plain-2009 12:44 am 10/23/2012

    That’s correct. Let’s wait and see.

    The sun is just starting to rise in the horizon. Let’s not jump the gun.

    With respect to [Bird/tree, etc] commentary I do not see any point of conflict.

    By the way I have never heard of Mr. Paul Broun; he seems to be a nice person.

    But certainly his personality does not agree well with what we expect from a House Representative.

    No doubt he is an intelligent, well-intentioned person that can do a lot for the benefit of the people he represents and for the people of the entire world.

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  16. 16. Plain-2009 1:05 am 10/23/2012

    I do not want to give rise to misunderstandings.
    I know nothing about Mr. Paul Broun.I am just learning about him.
    It is a little curious that he is in a Science Committee and (at the same time) says that Big Bang Theory and similar come straight from the pit of hell.
    It also sounds very curious to me that he belongs to the Tea Party.
    I have nothing against Mr. Broun or Tea Party members. I am very respectful of their point of view.
    I probably understand them better than he understands us, tough.
    I am very pro-science.

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  17. 17. Bird/tree/dinosaur/etc. geek 7:59 am 10/23/2012

    “”"No doubt he is an intelligent, well-intentioned person that can do a lot for the benefit of the people he represents and for the people of the entire world.”"”

    Go to this article and watch the video:
    http://blogs.scientificamerican.com/observations/2012/10/05/house-science-member-says-earth-is-9000-years-old/

    This man helps decide what is put into textbooks and who gets research grants. Other members of the House Science Committee inculde Dan Quayle’s son, two AGW denialists, and Todd “Legitimate rape” Akin the Magic Vagina Guy. See what I mean.

    Link to this
  18. 18. Plain-2009 4:04 am 10/24/2012

    Bird/tree, etc.
    I am going to look at that as soon as possible.
    But I am already worried about that; and at the same time confident that we can steer (if so required) things into the right direction.
    I appreciate your warning.

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  19. 19. Postman1 3:33 pm 10/25/2012

    Bird, another problem no one here has mentioned surprisingly, is the effect on global warming of all those dinosaurs flatulating. Aside from the smell, all that methane could spell disaster!

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  20. 20. Bird/tree/dinosaur/etc. geek 6:10 pm 10/25/2012

    Mailman: great joke! Seriously, though, that would be a significant problem with bringing back herbivorous dinosaurs, especially sauropods. I refer you to Scott Sampson’s “Dinosaur Oddessey” for a brief summary of dinosaur farts in the Morrison formation ecosystem.

    Link to this

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